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AIRCRAFT ELECTRICAL SYSTEM SAFETY
Wednesday, September 15, 1999
House of Representatives, Subcommittee on Oversight, Investigations and Emergency Management, Committee on Transportation and Infrastructure, Washington, D.C.
The subcommittee met, pursuant to call, at 2:05 p.m., in Room 2167 Rayburn House Office Building, Hon. Tillie K. Fowler [chairwoman of the subcommittee] Presiding.
Mrs. FOWLER. The meeting of the Subcommittee on Oversight, Investigation and Emergency Management will come to order. We have been waiting on our ranking member, Mr. Traficant, but he is held up on the floor. So he has given us permission, we are going to go ahead and get started because, you know, we have some witnesses here who have taken their time to be with us today and we want to go on and get started.
I want to thank all of you for coming today to participate in this very important hearing on aircraft electrical system safety. Today the subcommittee is going to examine recent advances that may improve the safety of aircraft electrical systems.
Aviation safety is a personal interest to me. First of all, like most Members of the Congress, I fly twice a week. And when I get in the seat of a plane, I want to be confident that everyone has done whatever is necessary to make the trip a safe one. And, secondly, having naval air bases in my district, I have been, for a number of years, watching how the Navy has tried to deal with concerns about electrical systems on aircraft.
I want to thank the Aviation Subcommittee for recognizing my personal interest in this issue and its cooperation in setting up this hearing. And I especially appreciate the assistance that was provided by Mr. Duncan, the chairman of the Aviation Subcommittee.
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Many of today's aircraft flight control systems have been redesigned from a cable-and-pulley system to new fly-by-wire systems. The new systems rely on electric signals driving electric motors. There has been a tremendous increase in the importance of electrical systems. For instance, not much more than 20 years ago aircraft had only a few feet of wiring installed. Today, some large aircraft have as much as 150 miles of wiring in them. This change is reflected in the causes of some aircraft accidents.
Today, wire and cable experts believe that old or damaged wiring may be among the weakest links in air safety. Fires and other hazards associated with faulty electrical systems pose a relatively large risk. In fact, a recent annual report listing causes of fatal accidents worldwide listed in-flight fires ahead of other more publicized categories such as icing, and wind shear. This chart that is over on the right, you may want to take a look at it later, but the chart shows that a major cause of in-flight fires are electrical faults, a wire-related problem.
You will also note on the chart that the fifth major cause of fatal accidents is fuel tank explosions, also often a wire-related problem. If you have combined the in-flight fires and the fuel tank explosions and the wire-related problems, this moves to the third position as a cause for fatal accidents. This chart does not include, I want to note, any data from TWA 800 or Swissair 111.
The three areas this hearing will focus on today indicate we may be able to significantly reduce the risk of in-flight fires in the future. These areas include, first, advances in wire technology. New state-of-the-art composite wire can provide a higher level of safety to the world of travelers by providing superior performance with much-improved reductions in flammability and minimal smoke generation.
Second is advances in circuit breaker sensors. These sensors have the ability to detect the distinctive differences between normal current and intermittent arcing conditions by opening the circuit. When a hazardous condition is sensed, safety is enhanced.
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And, third, advances in the electrical maintenance awareness. Inadvertent electrical wire damage has heightened our awareness of the need for improved maintenance practices.
I look forward to hearing the testimony from all of our witnesses today and working together on achieving our common goal of improved safety in aircraft electrical systems.
I would now like to recognize Mr. Terry, the vice chairman of our subcommittee, if he has an opening statement.
Mr. TERRY. No, but I will just make a couple of comments.
The importance of our hearing, looking into the issue of wiring, isn't only the frequency of flying by congressional members, but the public in general. And the survivability in a minivan that has a short in the wire, it is most likely going to be survivable by me and my family. This happens on an airline and the likelihood is that it is not survivable. That is why it is important that all of the agencies in Congress make it a priority, because what we are talking about is airline passenger safety here.
And so, what I want to hear today or what I want to learn today from these hearings is, what is the NTSB doing and what is the FAA doing and how have they handled the investigations of the past where they know that wiring is a cause or a contributing cause of a crash.
What pressures are they putting on airlines to remedy the possibility of on-board fires? That is where I think our responsibility lies. So I am anxious to hear the testimony of the officials that you have invited here to testify, and I thank you for putting this hearing together.
Mrs. FOWLER. Thank you, Mr. Terry.
If there are no other statements, at this time I will call the first panel. The first panel is Dr. Bernard Loeb, representing the National Transportation Safety Board; and Dr. Loeb is the director of the Office of Aviation Safety at the NTSB. With Dr. Loeb is Mr. John DeLisi, Deputy Chief of the Aviation Engineering Division in the Office of Aviation Safety. Dr. Loeb is uniquely qualified to discuss this subject as his office has recently released an addendum to the TWA 800 accident report.
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Before we proceed with your testimony, Dr. Loeb, we will swear you and Mr. DeLisi in as we do with all witnesses before this subcommittee. If you would please stand and raise your right hand.
[Witnesses sworn.]
Mrs. FOWLER. Thank you. Please be seated. In view of the fact that we have several witnesses before us this afternoon, I am asking each of the witnesses, if you could, summarize your testimony in about 5 minutes and then without objection, your full written statement will be included in the record.
We have a clock system with a series of lights. When it is yellow, it means the time is about to run out; when it is red, it means time has run out. So if we can agree with that system, it would help.
Dr. Loeb, if you would begin. Thank you.
TESTIMONY OF DR. BERNARD LOEB, DIRECTOR, OFFICE OF AVIATION SAFETY, NATIONAL TRANSPORTATION SAFETY BOARD, ACCOMPANIED BY JOHN DeLISI, DEPUTY CHIEF, AVIATION ENGINEERING DIVISION, OFFICE OF AVIATION SAFETY, NATIONAL TRANSPORTATION SAFETY BOARD
Dr. LOEB. Good morning, Madam Chairwoman and members of the committee. I am pleased to represent the National Transportation Safety Board today regarding aircraft electrical wiring issues.
Electrical systems are critical to the safe operation of transport category airplanes, and wiring is used to distribute power and communication signals throughout these systems. My testimony, as submitted for the record, summarizes some past accidents that involved wiring malfunctions and the resulting safety recommendations that the Board has issued. In my oral statement, I will focus primarily on wiring issues that have arisen during the investigation of the accident involving Trans World Airlines Flight 800.
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On July 17th, 1996, a Boeing 747, operated by TWA as Flight 800, crashed into the Atlantic Ocean shortly after takeoff from John F. Kennedy airport in New York, killing all 230 people aboard. We have determined that the fuel air vapor in the center wing fuel tank ignited, causing an explosion of the tank and the breakup of the airplane.
The Boeing 747 has an electronic fuel quantity indicating system that measures the amount of fuel aboard the airplane and displays that information in the cockpit. This system includes electrical probes that are mounted in each fuel tank, seven of which are in the center wing fuel tank.
The system is designed to carry a maximum of 26 volts with low current through Teflon-insulated wires. Although not yet complete, the investigation has uncovered several concerns about the center tank wiring. Investigators have learned that this wiring was routed in bundles with nearly 400 other wires, some of which carry up to 350 volts. The Safety Board has already recommended that the FAA require the center wing tank wiring to be separated from other wires to the maximum extent possible.
The FAA has responded by issuing an airworthiness directive mandating the separation and shielding of fuel quantity indicating system wiring in Boeing 747 and 737 aircraft. Safety Board investigators have also found that a connector on certain tank probes was designed in a manner that allows its sharp edges to cut through the insulation of the wiring which can create a spark gap. As a result, the Safety Board recommends the replacement of such connectors on fuel tank probes. Once again, the FAA responded by issuing an airworthiness directive to address this issue.
The Safety Board's investigations of wires, wire bundles and electrical connectors recovered from Flight 800 wreckage revealed fuel tank wiring that had been repaired, using Mylar tape and a string tie, wiring with insulation cracks that exposed the conductor—.
Mrs. FOWLER. Can I stop you right there? I want to make sure I heard you right.
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You said that some of the fuel tank wiring, the method by which it had been repaired, was using tape and string?
Dr. LOEB. The way that sounds is perhaps a little worse than it really is.
There is an approved repair procedure for certain uses in the aircraft wiring system that does allow that type of repair. It is not permissible on either of the Boeing design and airworthiness standards to do that in the fuel tank; and that is primarily the problem.
Mrs. FOWLER. Okay.
Dr. LOEB. We also found wire bundles contaminated with semiconductive residues, metal drill shavings along the path where the center tank wiring was routed.
In an effort to determine if these findings were unique to the Flight 800 airplane, or existed on other transport airplanes, the Board examined wiring on more than 20 other transport category airplanes and found accumulations of contaminants on wiring that included lint, grease, liquids, paper, metallic corrosion-inhibiting compounds, wire bundle clamps that cut into the wire when the rubber lining crumbles, shavings and cracks in the insulation of wire, deep enough to expose the conductor.
These findings have raised the Safety Board's concerns about the safety of electrical systems as airplanes age.
However, in recent industry meetings and seminars, operator personnel have questioned the merit of performing wiring inspections indicating that they have not detected significant discrepancies. This is certainly at odds with our findings.
It is important to note that we have not yet identified the ignition source that ignited the explosion on Flight 800. However, our wiring examinations and system examinations have shown us that it is very difficult to eliminate all potential ignition sources, and underscore our belief that the potential for the fuel vapors to be at an explosive level should be reduced as much as possible. The Safety Board's recommendations to the FAA on this issue are still open.
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That completes my statement and we will be pleased to answer any questions that you may have.
Mrs. FOWLER. Thank you very much.
I want to follow up with your statement. You said that you inspected over 20 planes and listed some the potential problems that you found in many of these planes.
Could you specifically tell us how many planes you did inspect and how many of these planes did you identify having potential problems such as deep cracks in the wiring?
Dr. LOEB. We have inspected at least 25 airplanes as a result of the TWA 800 investigation. Eighteen of these were airplanes that were essentially in the desert in moth-balled conditions, or sitting there waiting for disposition. They were older airplanes, many of them similar to the TWA Flight 800 airplane.
In addition, however, we had an opportunity to investigate seven additional airplanes that ranked from relatively newer or brand-new airplanes to fairly new airplanes that were actually in service, but had experienced some sort of an event, an incident. In all of them, we found some anomaly, either metal drill shavings or lint, and other anomalies similar to that found in the TWA 800 airplane.
Mrs. FOWLER. So in all 25 planes that you inspected you found some type of problem with the wiring?
Dr. LOEB. That is correct.
Mrs. FOWLER. I want to welcome Mr. Traficant, our ranking member, who has been on the floor as I stated earlier handling an amendment. We appreciate having you with us. We are starting our testimony from Dr. Loeb. I didn't know if you wanted to make a statement before we proceed further.
Mr. TRAFICANT. I don't know if you want me to make that statement now or maybe after the distinguished panel has gone forward.
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I want to apologize, I was a little bit late with that amendment.
Whichever you would prefer, Madam Chairwoman.
Mrs. FOWLER. Why don't we move on forward with Dr. Loeb.
Mr. TRAFICANT. That would be fine.
Mrs. FOWLER. I told them you were over there doing the House's work, offering the amendment. We appreciate you joining us.
Dr. Loeb, because I understand that TWA Flight 800 was primarily wired with noncomposite wiring. Roughly what proportion of the traveling public would you say are flying on aircraft today that are primarily wired with noncomposite wiring?
Dr. LOEB. I don't have an answer for that, but I do believe that the vast majority of airplanes are probably wired with wiring that is not of the nature of TKT or other composites.
Mrs. FOWLER. Mr. DeLisi.
Mr. DELISI. Some data that we have received from the FAA would indicate that starting in about '93 there are about 12 to 13 percent of the airplanes that have the composite type wire.
Mrs. FOWLER. So only 12 to 13 percent have the composite, and all the rest in the system have the noncomposite.
Mr. DELISI. Right.
Mrs. FOWLER. Thank you.
We are learning, as we stated earlier, that there are at least three ways to reduce the risk of fire on the aircraft. We talked about installing safer wire, better circuit breaker technology or improving airline maintenance practices. Based on what we know today, if you had to prioritize, which of these three would you consider to be a priority?
I know they're all three important.
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Dr. LOEB. I am not sure at this point that we are in a position to be able to prioritize; I hope that we will be able to in the late winter when we complete our work. And the reason I don't want to do that is because the very essence of some of the work we are doing is to try to determine just that.
I can tell you that certainly the arc fault detection capability, once it is readily available and practicable, would be a major enhancement because the circuit breakers that are now in airplanes simply are not designed to respond to an arc, which the arc fault detectors are.
Mrs. FOWLER. Okay. I know right now the major practice for inspecting wiring is visual wiring inspections. I don't know of any alternative inspection process, do we have any other technology to do that? How effective, truly, are visual wiring inspections?
Dr. LOEB. They can be effective for what can be seen. You can't inspect visually what you cannot see and unfortunately, the wires themselves are embedded in bundles of other wires. Only the surface wires are visible, and they are visible only on one side. Much of the wiring in airplanes is simply not visible, unless there is perhaps a deep check, or the wiring is exposed in some sort of situation where the airplane is essentially deskinned.
Mrs. FOWLER.T4 WE'VE BEEN MADE AWARE OF SOME FIELD TESTS, I BELIEVE, THAT INDICATE ABOUT 75 PERCENT OF THE WIRING PROBLEMS ARE MISSED BY VISUAL INSPECTION FOR THE VERY REASONS YOU ARE SAYING. WE NEED, I THINK, TO BE MOVING FORWARD TO SOME BETTER TECHNIQUES OF INSPECTING WIRING RATHER THAN VISUAL INSPECTIONS ALONE.
I want to—oh, I want to welcome Mr. Oberstar. So pleased to have you with us today. We are in the middle of questioning Dr. Loeb from the National Transportation Safety Board, and I was ending my questions. I was going to turn to Mr. Traficant.
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At the end of this panel, Mr. Oberstar, we were going to have other statements made by members, if you wanted to—if that would be fine with you. Great.
Mr. Traficant, do you have any questions for Dr. Loeb?
Mr. OBERSTAR. If I may, Madam Chairman, compliment you and Mr. Traficant on holding this hearing. I think it's a most important issue.
Mrs. FOWLER. We appreciate all of your help with this.
Mr. OBERSTAR. We have a splendid list of witnesses that are here. I read all their testimony last night and this morning. It's a subject that I have a very keen and deep and long-standing interest in.
Mrs. FOWLER. You have been a long-time advocate for airline safety. We appreciate all of your help on the hearing today.
I want to welcome Mr. Nadler, who also is here.
Mr. Traficant.
Mr. TRAFICANT. Madam Chairwoman, I have a number of questions, and I would like those questions to be submitted in writing to the panel and for them to answer them in writing in an expeditious manner. Naturally—any other questions, brought by any other panel members who would overlap my questions, naturally you could refrain from answering.
I just want to say, though, to this panel that we work very closely and looked closely in the matter of TWA Flight 800 and there have been an awful lot of people making judgments about the NTSB; and we found the NTSB had done a very good job, worked satisfactorily, diligently, was honorable, forthright and outright in what it had found to the American people.
So I just want to commend you, and my questions will be in writing.
So I will have a statement before the FAA testimony. Thank you.
Mrs. FOWLER. Mr. Terry. And as vice chairman of the subcommittee, after your questions if you would chair for just a few minutes for me, I would appreciate it.
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Mr. TERRY. [Presiding.] Sure. Anything for you.
A couple of questions arose in my mind during your answers to Chairman Fowler's questions. First of all, when you were talking about—you called them arc detection. That's circuit breakers that have some smartness, they can detect it or open the current so—open the circuit so the current doesn't flow, therefore eliminating the risk of fire in that wire. Is that essentially what happens?
Dr. LOEB. Yes. The circuit breakers really work on the principle of sensing heat. And therefore, even a very high energy electrical activity could produce heat, but if it does it for a very short period of time it will not trip a breaker. But an arc fault detector that is designed specifically for that could catch most, if not all, arcs.
Mr. TERRY. Well, the two thoughts that pop into my mind about that technology being readily available is, first of all, can that technology reasonably be retrofitted into the current inventory of planes, whatever sizes?
Dr. LOEB. You may hear from other witnesses, Congressman, on this issue who are more knowledgeable than I. Right now, we are in the position of studying this technology and trying to determine what we believe is now feasible and what needs to be explored and developed further. And it's likely, as a result of our investigation of TWA 800 and the completion of the report late this winter, that the Board may well be making recommendations on that. At this time I can't tell you whether the technology is in such a state that it can be retrofitted onto existing airplanes in any practicable way.
Mr. TERRY. That answer inherently anticipated my next follow-up question. And that is whether the technology, if mandated or implemented—first of all, remember, I am a layman. The last thing I know is airplane technology. But it seems to me that if we have a system that will shut off a current to serve wires because it senses heat, to me, that's a bad thing to have when all of a sudden your power is cut off to a certain area, unless you have redundancies built into the system.
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So the question is, is it a safer system? And that's—you said, in a sense, you're still studying that?
Dr. LOEB. I think there's no question that arc fault detectors will be an improvement. The only question is, when can they be implemented. Is it something that is practicable to go into new airplanes only, or can it be retrofitted into existing airplanes? We are simply not in a position to answer that right now.
However, there is no question that arc fault detectors will have the capacity to represent an improvement.
Mr. TERRY. Well, as a layman and a passenger, I would feel safer with that level of technology versus Tim Tool Time's answer of duct tape that seems to be the present choice right now, at least in your testimony.
And getting back to Chairman Fowler, I think we are all astounded to learn that some of your investigation shows that some of the wiring was taped and strung together. But you said that's not unusual for the industry, absent or outside of the fuselage area. I've got to tell you that's frightening.
Dr. LOEB. Let me try to clarify that.
If the procedure is done properly in the proper locations—and it is not a proper location inside the fuel tank, but inside the airplane if it is done properly and it is probably shrink-wrapped, heat-wrapped and covered, then it is an acceptable procedure. However, for a variety of reasons, including the chemistry that is inside the fuel tanks, it is not an approved procedure or a proper procedure for inside the fuel tank. That is what really was of concern to us.
Mr. TERRY. In connecting the dots on the TWA Flight 800, this finding was in the fuel tank area, right?
Dr. LOEB. It was.
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Mr. TERRY. I appreciate your time.
And, Mr. Nadler, do you have any questions?
Mr. NADLER. Yes. I apologize for coming late and if I ask anything you have already covered, accept my apology in advance.
Let me—you said that that's not an acceptable method within the fuel tank. Of course, the supposition is that an arcing from wiring in the fuel tank may have caused vapors to ignite on TWA 800. And, of course, we've got huge fleets of Boeing planes with similar wiring that go back 20 and 25 years, those 747s, 727s.
What are you doing, what is the FAA doing—and I know that they've ordered—I am not sure what they've ordered, something to look at all these fuel tanks.
What exactly has the FAA ordered to be done with all these older, existing planes that may have this kind of problem potentially in the fuel tanks and to what extent is a manual or visual inspection of these wires going to find all the flaws in the wiring?
Dr. LOEB. Well, let me start with the first question.
The FAA has done a number of things. They've ordered a number of inspections on the various Boeing airplanes, and they have issued rulemaking for the separation of wires that leads into the fuel tank from the other wires in the airplanes so that you can't inadvertently get a high voltage into a low voltage system that could create an ignition source in the tank. So there has been some action taken.
One of the difficulties is that visual inspections are extremely limited. You cannot detect faults that you cannot see. In some cases, if you do not move the wires or move the wire bundle, you may not see a fault that's right there in front of you because the insulation looks like it's together when in fact there's a crack in it. So the visual inspection process is limited, and there's lots and lots of wiring in an airplane that is not visually inspected.
Our overriding concern of course in the case of TWA 800 and any fuel tank is, it's extremely difficult at this time to be able to detect all possible faults in the wiring system. That is why we have asked the FAA to take action to reduce or eliminate the vapors being at an explosive level in the tank. We think that's the primary thing that needs to be done, because right now the process of trying to eliminate the ignition sources is very difficult.
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Mr. NADLER. If there are vapors in the tank, is there such a thing as a safe threshold level below which the vapors cannot explode or ignite?
Dr. LOEB. Depending on the fuel that is being used, Jet A being a common fuel, but not the only one that's used worldwide, there are temperature levels below which the fuel will not ignite because it will not be at the lower explosive level.
Mr. NADLER. But the temperature is determined by the wire and the arcing, not by the amount of fuel vapors?
Dr. LOEB. The temperature in the tank is primarily determined by the amount of heat that goes into it from the primary heat source, which in the case of the Boeing property products are the heat exchangers that sit right under the fuel tank.
Mr. NADLER. But isn't the arcing the source of the heat that would ignite the vapors?
Dr. LOEB. The arcing is the source of energy that will ignite the vapors. But if the vapors are not at an explosive level because the temperature of the fuel hasn't gotten to that level, even if you have an arc it will not cause an explosion.
Mr. NADLER. So I take it you're suggesting to the FAA that these heat exchangers, I think you called them, be cooler or moved?
Dr. LOEB. We haven't suggested that specific thing, although we have addressed a number of things such as the possibility of insulating below the fuel tank in between the fuel tank and the heat exchangers; also the possibility of carriage of some fuel in the center fuel tank that, upon takeoff, you would put cooler fuel in.
We have suggested a number of things, alerting a number of ways in which they may look at it. We have not made a recommendation that they may take a specific action.
Mr. NADLER. By when could the traveling public expect that we have assurances that measures have been taken to make sure that you don't get a temperature in those tanks sufficient to ignite vapors?
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Dr. LOEB. You'll have to address that to the FAA, who will come on after this.
Mr. NADLER. Thank you.
Mr. TERRY. Mr. Ranking Member Oberstar, if you would like to make a statement, then you also have 5 minutes to ask questions if you wish.
Mr. OBERSTAR. Thank you very much. I have a statement which I would ask unanimous consent to include in the record.I want to compliment across the Board, Dr. Loeb, as always I am a great fan of the National Transportation Safety Board. The Board has contributed enormously to making aviation safer and the safest mode of transportation. We continue to have high expectations for aviation, higher than for any other mode of transportation.
And this hearing is not on TWA 800, although it was that tragedy that helped trigger public concern and the attention of this committee, and the more recent Swissair tragedy. But just so it's clear, because it certainly was not to a number of viewers this morning on the C-SPAN program that I participated in, the Board has not issued its final findings, conclusions, recommendations on TWA 800.
Dr. LOEB. That is correct, Congressman.
Mr. OBERSTAR. When do you expect to be able to do that?
Dr. LOEB. We hope to be able to do that in the late winter. There are still, unfortunately, a number of tests, and especially wiring tests, that are still under way. We have a set of tests that we want to do that we need a Boeing 747 for, and we have one that's going to become available in early November. We simply can't proceed until we've completed those.
Mr. OBERSTAR. This matter of wiring, it is a very serious issue that the general public has not thought about and many aviation safety specialists have not given a great deal of thought to, but when you consider the evolution of aviation, the older version aircraft 40 years ago had very little wiring, and it wasn't a major problem even 30 years ago; but with aircraft in the last 20 years, wiring is much more extensive, more complex. And as newer systems have been added to aircraft, their power load has increased and put pressure on the existing, aging wiring systems. And you have both AC and DC current now on board aircraft of various types.
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And on average I would say in a 737, 800 to a —757, -67, 747—upwards of 100 miles of wiring on board an aircraft. It is not a simple matter to pull this out and replace it. There are costs and also very complex issues.
Now, as I have studied the issue and read and followed the Board's work and the FAA's work—I would like to compliment Mr. McSweeny in the job he is done in this arena—vibration, moisture, temperature and location are the most critical factors. Initial installation of wiring, threading it through the stringers and through the holes in the stringers is a very sensitive matter, and that has to be done with the greatest of care. And the FAA does have guidance for manufacturers.
There is also guidance for maintenance, as maintenance is done on aircraft and the insulation pulled out, wiring disturbed, stringers inspected, and parts moved and then pushed back in. Your Board inspectors have found evidence of screwdrivers scraping the insulation away from wiring, exposing bare wire either to each other or to metal portions of the stringers and the internal structure of aircraft.
And then there are the brackets that clamp the wires that chafe, shavings, metal chips from maintenance that fall on top of these wires, moisture in the form of oil, grease, or just water, condensation, wire bundles that—in the photos in the back of the room, that are improperly joined or cross each other. All of those are flashpoint for tragedy to occur.
Has the Board—of course, what I am getting at is in this era of aging aircraft, maintenance with our 1991 act that required complete tear-down at certain points in the aircraft's life, down to bare metal, to inspect the structures. And there are other things as well, but we are principally focusing on structures now; you have to include systems along with structures, a holistic approach.
Is the Board making recommendations or preparing to make recommendations in light of the '84 Northwest DC-10 near-tragic accident on board the aircraft; the 1991 Delta L-1011, the Cessna jet in '97; the 767 in '98, the basis of those and others, making recommendations that deal with holistic approach to maintenance, to particular care and practice that mechanics must follow in maintenance, in initial manufacture of aircraft?
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And are you prepared to make further recommendations about separation of wiring, protection of wiring, and the insulation on wiring?
Dr. LOEB. That's quite a broad question, Congressman. And the short answer is yes.
Over the last 15 years or so, we've investigated 15 electrical events in transport category airplanes. You mentioned a number of them just a couple minutes ago. As a result of those incidents, we've made nearly 30 recommendations. Most of those recommendations have not been holistic. They have been to inspect this or fix this, looking at each and every one of these events almost as a separate event.
We have begun in the last few years to look at this issue in a broader perspective. Right now the Safety Board is considering what kinds of recommendations it should make that would be looking at treating the aging systems issue more globally.
Mr. OBERSTAR. In subsequent testimony to be delivered by Air Line Pilots Association, a witness says, ''Polyimide-only, as opposed to composite polyimide, wire insulation is not satisfactory in any application that carries a significant load.'' what's your view on that matter? Of course the concern is wherever you have a significant carbon factor insulation, there's a source of ignition, a source of further arcing.
Dr. LOEB. For the phenomenon known as arc tracking, which is where you have essentially an arcing and it progresses down the insulation and chars the insulation, the TKT insulations appear to have a major advantage in their ability to smother what otherwise would be a process that would continue. Unfortunately, that's not the only and may not be the most significant problem in the electrical wiring systems. It is a problem, and it's something that can be treated. And certainly the composite wires, especially those that are of the variety of the TKTs, seem to handle that. But there are other problems.
Any time you get a wire insulation that is cracked, down to the bare conductor, and that bare conductor can come in contact with other wire or metal, you have the potential for an arc. Drill shavings, and all the other kinds of things that exist for maintenance going on in airplanes—by the way, we've seen them sometimes in brand-new airplanes—when you have that, you have a problem that you still have to deal with. It is not clear that composite insulations would necessarily be much better.
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Now, having said that, one of the advantages to Kapton, which is one of the wires that has the arc tracking label attached to it, is that it is a tough insulation and a fairly good insulator. Therefore, it's more impervious—not completely by any means—to some of the deficiencies that we have seen in terms of the cracking and so forth. The TKT wiring does seem to have some benefits in that direction.
Mr. OBERSTAR. A couple or one last point in your response. Circuit breakers do not protect from overheating or arcing, they may stop it from—but the arc fault interrupter technology seems to have the capability of providing a broader range of protection.
Has the Board staff investigated this application?
Dr. LOEB. We are familiar—.
Mr. OBERSTAR. It can sense current change and cut off the circuit apparently.
Dr. LOEB. We are familiar with the technology. In fact, we have been studying a number of the new technologies that are out there for both protection and for inspection. I anticipate that the Safety Board will be deliberating on a number of potential recommendations that will go toward the new technologies.
Mrs. FOWLER. The FAA has adopted 20-some or now it's announced 20-some airworthiness directives, some of which have been recommended by the Board.
Do you feel the FAA has been responsive to your—.
Dr. LOEB. I think the FAA has been extremely responsive to the specific recommendations that we've made in terms of both inspection and attempts to provide some separation of the wiring. I think there's still a lot more that needs to be done on the fuel tank issue.
Mr. OBERSTAR. That remains an open question.
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Thank you, Madam Chair.
Mrs. FOWLER. Thank you, Mr. Oberstar.
I want to welcome Congressman Isakson to our hearing this afternoon. Thank you for being with us.
I understand—Mr. Traficant, do you have another question?
Mr. TRAFICANT. I do want to ask one question just for brief response.
To this point, are you satisfied with both the FAA efforts and the industry efforts to address the problems with aircraft wiring, specifically those generated naturally from aging aircraft systems?
Dr. LOEB. Before I answer your question, I think before I go back and the chairman has my hide, I do need to thank the committee and especially you, Congressman Traficant and Congressman Oberstar, for the wonderful words you have said about the Safety Board. They feel very good to a long-term civil servant who has spent 23 years at the Safety Board, and I thank you for that.
Now, to get to the question you asked, I think these latest accidents and the activities that the Safety Board has undertaken as a result of its investigation have made a change in the way the industry is now viewing the issue of electrical wiring. Certainly we are pleased that the FAA is looking at the aging wiring issue and the aging systems issue.
Having said that, we are concerned that as a result of inspections that have been done by the industry, they seem to be defining the problems that we have seen and that they are seeing as not terribly significant. That raises questions in our minds as to what the ultimate outcome will be. I hope that with the help of the Congress, we'll get the industry and the FAA to move quickly on these issues, and especially address this issue of the aging systems and wires.
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Mr. TRAFICANT. I want to thank you and tell you something, that I am a supporter of the Board, and one of your biggest supporters in the Congress is our chairman, Mr. Oberstar. He has worked very hard to inform us of your role, and we've come to know more about aviation safety from that. I appreciate that, Mr. Chairman. So we appreciate your effort.
I do have a number of questions, Madam Chairwoman, I would appreciate those that have not been addressed to be answered and sent to us in writing. Thank you.
Mrs. FOWLER. Are there any further questions by members of the subcommittee? I know there will be some that I and others will submit in writing also, that we would appreciate being answered for the record.
I want to thank you, Dr. Loeb and Mr. DeLisi, thank you for your excellent testimony, and add my thanks to those that you have been hearing about the excellent work the National Safety Board does in protecting our traveling public. Sometimes we don't say we appreciate it enough, but long-time working civil servants are appreciated up here. We know what good work you have been doing, and we look forward to continuing to work with you as we try to make air travel even safer for the traveling public. So thank you so much for being with us this afternoon.
Dr. LOEB. We appreciate that. Thank you.
Mrs. FOWLER. Before I call the second panel I will turn to my ranking member, Mr. Traficant, and give him the opportunity to give his opening statement that he was not able to give earlier.
Mr. TRAFICANT. I want to thank you, Madam Chairwoman. I was on the floor with specific amendments to other bills. One of them did involve a Federal aviation concern, aviation research and development through the Science Committee; and one of the amendments dealt with an aviation laser visual guidance system that I am hoping they will continue to research.
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But having said that, I want to make this statement because I have worked very closely with not only the National Transportation Safety Board, Federal Aviation Administration and the Boeing Company, and I wanted to make a statement relative to some of the dynamics of certain accidents. And I wanted to take this time to also commend my Administrative Assistant, Paul Marcone; the two of us have spent an awful lot of time conferring on a couple of issues, the issue being aircraft wiring, naturally generated by the disaster of TWA Flight 800, the accident off the coast of Long Island, and Swissair Flight 111 off the coast of Nova Scotia. Both of these focused on both the NTSB's and FAA's attention to potential problems with wiring, specifically and essentially in older aircraft.
And Chairwoman Fowler, you're commended for having this hearing. I think you will advance aviation safety because of it.
As a result of those two flights and disasters and subsequent investigations, the Board has made a number of recommendations on how to improve safety relative to such wiring. FAA has issued a worthiness directive in response to a number of those recommendations. For example, the Board recommended that low voltage wires, as stated earlier, be separated from high voltage wires. The FAA issued ADs mandating the separation and shielding of the fuel quantity indicator system wiring in Boeing 747s and -37s. It is good to note that the FAA continues to examine these issues, and I have full confidence in the FAA, that they will continue to take appropriate and prudent actions to improve safety.
But I want to make a point with Flight 800. The NTSB, through a process of gathering evidence, had determined—not final, as Chairman Oberstar, Ranking Member Oberstar had stated, after an exhaustive review, but the fuel air vapor in the center fuel tank ignited causing an explosion and disaster. The NTSB has not identified the ignition source at this point that sparked that explosion, and I hope that the rudimentary evidence of such can be attained.
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But the Board's investigation did reveal problems with the wiring, including the fact that some fuel tank wiring had been repaired using string and adhesive tape—that has been discussed earlier—wiring with insulation cracks that exposed a conductor, as Mr. Oberstar pointed out, wire bundles contaminated with semiconductive residues and metal drill shavings along the path where wiring was routed.
The Board also examined wiring on more than 20 other transport planes and found similar problems.
They did a thorough job in attempting to isolate the specific causations that brought about those disasters. They are to be commended for their exhaustive investigation. So there is no smoking gun; we don't have the source.
But it's important to note that the Board has yet to recover some key sections of Flight 800's wiring, including some of the wiring bundles that went into the center tank that were the focus of Mr. Oberstar's concerns.
I understand from the question that I asked, the one question of the Board, that they are concerned about the FAA
perhaps not moving fast enough to address some of the problems they are concerned with, specifically about aging aircraft.
As a result of my work with Mr. Marcone in examining the Flight 800 tragedy, I do admire the professionals at the Board level. They play, Madam Chairwoman, a vital role in ensuring air safety. They're doing their job and their concerns are to be noted here.
But now, having said that, I think the FAA, after my investigation and further review, is taking proper approaches at a level that they can control. They have moved in a methodical, but steady fashion to address many of those problems the Board has, in fact, established.
One of the things the FAA has done is establish the aging transport systems rulemaking advisory committee. I think it's a very important committee because of the issue of aging aircraft. This panel is looking at a wide range of issues, including inspection and maintenance practice improvements, improved design practices, training, improved system data reporting and corrective actions.
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Without a doubt, the FAA is on the right track, and I want the record to reflect that.
Most of the wiring problems discussed today are being addressed through improved inspection and maintenance practices as well as recommended design alterations. But because of the sensational reporting of the Flight 800 tragedy, I want to commend Boeing, who have taken some hits, about the excellent work they have done in the area, participating with and offering their help to this investigation.
Boeing has established wiring safety and performance requirements that now not only meet but generally exceed FAA standards. The industry must look hard at them, as Congress should. They are standards that should be met. Boeing continues to work cooperatively with the board and the FAA, as well as their customers, to make those necessary changes to wiring requirements and to maintenance and insulation practices. And I want to mention that so that the flying public will know that these concerns are being addressed and that Congress is providing oversight on these issues to ensure that those standards are met and continue to be maintained.
Naturally, the examination of wiring will be a key focus. The Congress of the United States wants all faulty wiring to be repaired and replaced, and that the system to monitor it and inspect it is one that is diligently attended to, and the Congress of the United States must feel comfortable with the efforts of all involved.
But I want to commend the board, the FAA, and Boeing for their efforts. Thank you.
Mr. TERRY. [Presiding]. Thank you, Mr. Traficant.
The Chair now calls the witnesses for the second panel. First, Captain Paul McCarthy of the Airline Pilots Association, International, the ALPA. Next, we have Mr. Richard Healing, director of Safety and Survivability for the Department of the Navy. Mr. Healing is here today representing the Aircraft Wire and Inert Gas Generator Working Group. It is a collective group composed of aviation industry and Government personnel. The working group's purpose is to combine resources in order to find effective solutions to wiring problems and in-flight fires. We also have Mr. Armin Bruning, President of the Lectromechanical Design Company. Close enough until you start. And, finally, we have Mr. Michael Roberson, representing Tensolite High Performance Cable & Interconnect Systems. Mr. Roberson is standing in for Mr. John Berlin, president of Tensolite, who was trapped by Hurricane Floyd.
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TESTIMONY OF RICHARD HEALING, OFFICE OF THE ASSISTANT SECRETARY OF THE NAVY, DIRECTOR, NAVY SAFETY AND SURVIVABILITY, AND FOUNDER, AIRCRAFT WIRE AND INERT GAS GENERATOR WORKING GROUP (AWIGG); CAPT. PAUL MCCARTHY, EXECUTIVE, AIR SAFETY CHAIRMAN, AIR LINE PILOTS ASSOCIATION, INTERNATIONAL (ALPA); ARMIN M. BRUNING, PH.D., PRESIDENT, LECTROMECHANICAL DESIGN CO.; MICHAEL ROBERSON, ON BEHALF OF JOHN E. BERLIN, PRESIDENT, TENSOLITE, CO.
Mr. TERRY. Gentlemen, please stand and raise your hands, right hands.
We ask that you summarize your testimony in 5 minutes and, without objection, your full written statements will be included in the record. We will withhold questions until all panel members have testified.
Our first witness is Captain Paul McCarthy. Please proceed.
Mr. MCCARTHY. Mr. Chairman and members of the subcommittee, I am Captain Paul McCarthy, Executive Air Safety Chairman of the Airline Pilots Association. I appreciate this opportunity to discuss deficiencies associated with the wiring and circuit protection practices in today's transport aircraft.
I wish to make it clear that nothing I say here should be construed as relating to any particular accident. I also want to make it clear that we are not trying to issue any sort of general alarm about wiring concerns. Our members continue to operate these airliners with confidence in their airworthiness.
Having said that, I appear before you today to emphasize certain wiring deficiencies in order that we may correct existing problems and ensure safer aircraft in the future. First generation airliners had a relatively minimal need for wiring. Times and technology have changed. Modern transports are very different from early jet airliners.
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These aircraft can contain nearly 200 miles of wiring. These wires are quite thin and their insulation even thinner, often about the thickness of three human hairs. These wires are subject to deterioration from aging as well as mechanical damage from maintenance activity. These factors have combined to increase the incidence of wire-related aircraft safety problems, including short-circuits, electrical equipment malfunctions and failures, and fire.
We now know that wiring insulation deteriorates with age. Laymen tend to think of aging only in terms of elapsed time. However, aircraft wiring insulation aging rate is also a function of the operating environment and conditions. This aging rate is principally affected by four factors: vibration, moisture, heat, and mechanical stress. These factors vary throughout the aircraft, and certain insulation types are more vulnerable to these factors than others. Thus, the aging rates will vary.
One of the initial consequences of this insulation deterioration is a phenomenon known as ''arc tracking.'' in essence, as the insulation deteriorates from aging or mechanical manipulation, a conductive path is formed on the outside of the insulation. This type of failure only occurs in insulation types with a high carbon content, such as polyimide, found in, for example, Kapton wiring. At some point this conducted path can become sufficient to cause significant failures and problems, including fire.
With the exception of possible intermittent operating anomalies, neither the flight crew nor the maintenance personnel will have any direct indication that conditions to support arc tracking are developing. Normal circuit breakers will not protect against such events. It is not difficult to envision the complexity or severity of problems that could arise from arcing in a wire bundle which contains a large number of wires from many different systems, as is commonly found throughout the aircraft.
The federal air regulations, which regulate the installation of electrical equipment on today's aircraft, were last revised over 20 years ago. These regulations, and a related FAA advisory circular, are outdated and relatively vague. Much of the determination as to what constitutes good installation and maintenance practice is left up to the discretion of the manufacturers and the operators.
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Aircraft equipment and wiring have changed a great deal since the FAA guidance was last revised. These changes and the effects of aging wiring must be accounted for in revised regulations and practices. ALPA is a member of the FAA's Aging Transport Systems Rulemaking Advisory Committee, which is considering these issues with a view towards regulatory and advisory reform.
As described previously, insulation aging and deterioration initiate the arc tracking process, which grows over time. Initially, this phenomenon will either not manifest itself at all, or only as intermittent anomalies. Eventually, it can increase to a point where it can cause catastrophic failure of a number of wires and systems. Existing design fabrication and maintenance standards rely on circuit breakers to prevent damage and fires from electrical wiring problems. But, again, these circuit breakers do not protect against arc faults.
ALPA believes new technologies which can protect against such faults hold great promise for improving and ensuring the safety of modern wire-intensive transport aircraft. Such technology must be perfected and installed without delay.
ALPA would propose the following recommendations: enhance FAR 25.1353 and Advisory Circular 43.13. As mentioned, existing guidance does not adequately address current technologies and practices; revamp design and installation practices currently in use. Specific areas to be addressed should include power sources, intermixing of insulation types in a single wire bundle, bundling methods, and circuit breaker technology. And, finally, evaluate and incorporate alternative single-transmission methods, including fiberoptics, infrared and frequency modulated radio technologies.
Mr. Chairman, thank you again for the opportunity to appear before you, and I would be happy to answer any questions you and the members of the subcommittee may have.
Mr. TERRY. Thank you, Captain.
Next is Mr. Richard Healing. Please proceed.
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Mr. HEALING. Mr. Chairman and Members of Congress, I am Richard Healing, the director of Navy Safety and Survivability. I am honored to have been asked to testify on the issue of aircraft wiring and inspection techniques and other elements that contribute to aviation safety.
The aviation transportation system in the United States is a nearly perfect system that delivers safe and reliable transportation to millions of travelers every year. Despite that high level of quality and reliability, there are questions following any aviation accident asking what might have been done differently to avoid the loss of life. I will summarize the actions I took as director of Safety and Survivability for the Navy, addressing just some of those questions, in particular those related to aircraft wiring and on-board fires that may have resulted from degraded wire condition.
For a perspective, it should be noted that the Navy operates more than 4,000 aircraft to accomplish its missions in circumstances that vary from intense carrier operations in the far corners of the Earth to commercial-like logistics in passenger transportation.
Prior to 1980, the Navy had experienced fires on board aircraft that were ultimately traced to electrical failure. In some cases it was determined to be failure of wire insulation degraded by exposure to the harsh operating environment of the Navy and the cleaning compounds that we routinely use. We conducted extensive research to determine conclusively what caused the failures, decided on a remedial action plan, and took action supported by the evidence on a case-by-case basis.
Using various inspection techniques, removing suspects wires and changing wire specifications, we believe the Navy has successfully eliminated about 88 percent of the risks that had previously existed.
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In the period from January of 1980 through June of 1998, our accident investigators concluded that seven major accidents were caused by electrical wiring failure. In the same time period, 469 wiring-related events were documented, 164 of those events involving fire on the aircraft. The problem is being better managed, but it clearly has not been completely eliminated.
Following the TWA 800 tragedy in 1996, I wondered if the knowledge we had gained from research into the Navy's aircraft wiring problems had been effectively transferred to the commercial aviation community. I queried some safety professionals and associates, ultimately determining that we should act to ensure that such information was fully and effectively shared with all other parties having an interest, especially from the safety perspective.
It was our belief that open communication among all the participants in the aviation community, and opening the door to new applications and emerging technologies from any source, would provide the best possible chance for improvement.
On that basis, I founded AWIGG, the Aircraft Wire and Inert Generator Working Group, inviting everyone to participate as a forum for the exchange of information on the best existing and emerging technologies and techniques from both military and commercial aviation. The scope of our effort includes the full spectrum of information related to in-flight fires, not just wire insulation.
In four AWIGG meetings held to date, we have reviewed considerable information in the areas of wiring inspection, wire insulation technologies, fire detection and extinguishing methods, halon alternatives, enhanced circuit breaker technology, inert gas and fine water mist fire suppression concepts, and alternative materials to things that are flammable.
We now know that the aviation circuit breakers in use today are not capable of detailing intermittent arc faults that can occur in degraded wiring. Enhanced circuit breakers, based on the same concept in use in household ground fault interrupts, GFIs, should be rapidly developed, prototyped, and validated for aviation use. We also believe that Navy-developed fine water mist technology can be applied to cargo and passenger compartments as a means of suppressing fires.
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Based on the Navy's successes with halon substitutes, such as inert gas and HFC 125, further research into application of those technologies to commercial aviation is justified. New wiring inspection and testing methods that are nondestructive and easy to perform must be developed and implemented. Emerging concepts offer great opportunity, well worth the investment required to validate and produce reliable and affordable systems.
The bottom line here, from my personal point of view, is that improvements can and should be made as rapidly as possible because of the potential benefit to safer air travel globally for all people. I appreciate Congress' interest in these issues and encourage the committee to consider ways to assist in this effort, even to the point of considering means of providing immediate resources to complete validation work and to implement critical risk management technologies that are known to us today but not yet in actual use.
Thank you for the opportunity to testify on this very critical aviation safety issue, and thank you again for your interest.
Mr. TERRY. Thank you, Mr. Healing.
Next is Mr. Bruning. Please proceed.
Mr. BRUNING. My name is Armin Bruning, I am president of the Lectromechanical Design Company of Dulles, Virginia. I have degrees in electrical engineering, mathematics, and a doctorate in the physics of electrical engineering. My company has studied, researched, and made countless scientific measurements of the age and condition of aircraft wiring since about 1985. We have worked with many types of in-service aircraft in the Netherlands, Great Britain, Canada, and the United States.
Please take the piece of straight wire that is in front of you, bend it, and attempt to crack it across the edge of your fingernail. This is new aircraft wire. Take the other twisted pair, which has been aged in our laboratory under the conditions that cause it to deteriorate in military and commercial aircraft. Notice how easily it cracks when you bend it and twist it. The insulation is the yellow coating which assures that electricity does not leak from the conductor. Cracks in the electric wire's insulation allow current to leak through, which can result in an electric arc and which can lead to in-flight fires.
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Issue number one. Each wire type has its unique advantages and disadvantages. Different wires respond differently to outside conditions, such as heat, abrasion, moisture and strain. Competent design, manufacturing, and maintenance practices should always be considered to accommodate to these differences. No one wire type presently on aircraft is impervious to all of the elements that may affect it.
Please note there are advances in wire insulation technology that appear to offer significantly improved performance. This does not, however, address the shorter-term challenge of existing aging wire on aircraft.
Issue number two. Does aging aircraft wiring become a hazard on commercial aircraft? You have just seen how delicate electrical insulation is. This is an organic plastic material and it ages. I can say unequivocally and with great certainty we know that all aging wiring presently installed can pose a risk to safety and operation of flight.
Issue three. Are visual inspections a sufficient means for determining the condition of aircraft wiring? Visual inspection is the predominant method used by aircraft operators to inspect aircraft wiring. Visual inspection alone is not an adequate means of determining the condition and chemical age of a wire.
Please understand, cracks in the insulation, smaller than a human hair, which you cannot see, can cause operational problems or loss of an aircraft. Thick bundles of wire conceal most wires and their faults from view. Clamps, ties, and other equipment can damage wire and hide insulation breaks. Wire insulation may look to be in perfect condition; but as it becomes aged, it becomes weak, so that a slight increase in stress or vibration can lead to a dangerous failure in flight.
The insulation's weakness cannot be judged by the chronological age of the aircraft or wire. Advanced inspection techniques, perfected by several companies, including my own, can detect as much as three times the amount of hazardous wire as compared to visual inspections alone. These methods, coupled with other operational changes, have resulted in substantial reduction in the number of on-board fires for our customers, in one case by 88 percent over a period of 5 years.
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Issue number four. Steps my company has taken to reduce wire events in military aircraft that can be extended to the commercial industry: One repair system we use on active aircraft makes a complete nondestructive test of wiring. This locates existing insulation breaks. In this system called DelTest, the wire is repaired as the defects are found and the aircraft is returned to operational service. A second preventive maintenance technique we have developed and successfully used is illustrated in a chart which shows identification by zone of those areas which are in danger, allowing the maintenance manager to take proactive action before the wire fails.
In summary, an aircraft's electrical system, its installation and ongoing care, should command the same consideration that other critical systems receive. In our opinion, there should be no aircraft operator that does not adopt an advanced proactive wiring maintenance program. This is especially important over the next 5 to 10 years until the new technology comes on line. Thank you.
Mrs. FOWLER. Thank you, Dr. Bruning.
Mr. Michael Roberson, if you could proceed. Thank you.
Mr. ROBERSON. Thank you. On behalf of John Berlin, president of Tensolite Company, I want to thank Chairman Fowler and the members of the subcommittee for inviting us to speak on the issue of aircraft electrical system safety. The circumstances surrounding Hurricaine Floyd prevented Mr. Berlin's attendance at today's hearing, so I am afraid you are stuck with one of his in-house lawyers.
We appreciate having the opportunity to share Tensolite's experience with our development and advancement of aircraft electrical wiring. Tensolite, a manufacturer of high-performance wire and cable, has been a supplier of highly engineered aircraft electrical wire insulation systems to the aerospace industry for over 25 years. With assistance from major aerospace manufacturers, Tensolite has developed a composite tape wire technology that will become the next generation of airframe wire. Our comments today will center on aircraft electrical wiring and the recent technical advancements that have made this product state of the art in safety performance.
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During the '70s and '80s, the predominant insulation materials used for aircraft wiring were aromatic polyamides and cross-linked ETFE, both noncomposite wires. Many commercial airplanes flying today are wired with one of these insulation systems.
During the 1980s, the arc track performance of these wires became a major industry issue. In fact, some aircraft manufacturers do not consider cross-linked ETFE an acceptable wire construction for use in the pressurized zone of the aircraft due to the insulation's poor flammability and smoke-generation properties.
During the late '80s, the aerospace industry started testing new insulation materials to improve electrical, thermal, and mechanical performance. Between February of 1989 and January 1991, McDonnell Douglas and the United States Air Force conducted comprehensive studies directed at finding improved aerospace airframe wire constructions. This study led to composite tape, or hybrid insulation, which was identified as having non-arc tracking characteristics, good chemical resistance, excellent handling properties, and superior mechanical properties at high temperatures.
In 1995, another study was performed by the FAA and industry representatives which further demonstrated superiority of the composite wire technology. This report, titled ''The Increased Safety Factor With Hybrid Wire Constructions,'' concluded that the aerospace industry had successfully identified composite insulation as a new wire construction with the increased safety factors of improved arc-track resistance, virtually zero smoke generation, and excellent flammability resistance.
With these studies in hand, several major aerospace manufacturers moved rapidly during the early 1990s to develop composite wire construction for their programs. Issues such as compatibility with current manufacturing processes, improved mechanical and electrical performance, cost and multiple supply source availability all were considered. Boeing led the development of composite airframe wiring with the issuance of its BMS 13-60. Boeing began using 13-60 in 1993. By 1995, McDonnell Douglas, Lockheed, and Jet Propulsion Laboratory all followed Boeing's lead.
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In 1998, the Department of Defense's single process initiative spurred McDonnell Douglas to standardize the use of composite wiring on all military aircraft production. The composite wire saved weight, reduced compartmental complexity, improved the safety of the aircraft and produced considerable cost reductions. Many opportunities remain today for composite wiring, especially in other major airframe markets, such as regional jet aircraft, the fastest growing segment of the aerospace market, business jet, and propeller-driven aircraft.
The recent air tragedies and the concern over the safety of this Nation's commercial aircraft fleet have heightened the awareness surrounding the electrical aircraft wiring. There is a renewed emphasis on preventing in-flight fires and smoke. The FAA's aging aircraft research and development program is studying the issues related to older aircraft and the service life of airframe wiring. Composite wire technology must become an integral part of the aging aircraft study. Composite wiring offers maintenance and repair facilities, the advantage of being a universal solution to rewiring activities.
The composite wire can be applied in almost any area of the aircraft. Standardization of this state-of-the-art technology will clearly reduce the risks associated to misapplication of wiring in elevated temperature environments. The federal guidelines for airframe wire flammability found in 14 CFR, part 25, were written over 20 years ago and simply do not address such vital issues as smoke generation and electrical arc tracking of airframe wiring. The current guidelines provide little direction for the application of electrical wiring in an airframe environment, and we believe the federal standards must recognize the current available technology.
This technology has shown, through numerous studies, to reduce or eliminate electrical arcing, excessive flammability and smoke generation. Standardizing a composite wire as a minimum performance requirement should remove wire and cable as a variable when discussing in-flight fire and smoke and represents a proactive step in getting ahead of the problem, something that the FAA has publicly discussed as a way to improve safety. The adoption of the composite wire will provides a margin of safety for all new aircraft and serve to raise the commercial fleet to a higher level of safety.
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In closing, the composite wire insulation technology is the most advanced wire construction available. It offers the best balance of engineering properties and provides the optimum factor of safety needed to perform within the harsh environment of an airplane. Composite wire is the state-of-the-art technology and must become the standard for airflame wire safety and performance.
On behalf of Tensolite, I would like to thank Chairman Fowler, the subcommittee, and the FAA for their continued commitment to the improvement of aviation standards and safety. Thank you.
Mrs. FOWLER. Thank you, Mr. Roberson.
I want to thank each member of the panel for their testimony, and we would like to ask some questions now.
Mr. Healing, you stated in your testimony that the Navy requires composite wiring on its aircraft today. And as Mr. Roberson has stated as part of his testimony, I think all of the military are now. Can you tell my why, when the Navy does not allow the use of noncomposites wire on any of its new aircraft, it is still being installed on some commercial aircraft?
Mr. HEALING. I don't feel fully qualified to answer that, because I believe the domain of the commercial aircraft is really in the FAA's responsibilities.
Mrs. FOWLER. Well, explain why the Navy did away with using noncomposite wire.
Mr. HEALING. The Navy has continually sought to use the best available technologies. And for the last 15 years or so, we have used the cross-linked ETFE as the standard wire of choice. We are constantly looking for better products. When they become available, we will use them and we will standardize them on our new construction aircraft.
I think that one of the key concerns is that the affordability of removing wire from older aircraft, or the aging aircraft, is probably the largest reason that it is difficult to think in terms of retrofit. But forward fit, we're always looking for the best wire for the application for which it is intended. And we also have found out through the AWIGG working group, that not every application is filled by one type of wire. We use different types of wire depending on the application, too.
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So I can talk to what the Navy has done and tell you, assure you, actually, that we're looking constantly for the best possible solutions.
Mrs. FOWLER. Well, based on the Navy's experience with these various wire types used in Navy aircraft, are there any recommendations to the FAA that you might have regarding updating FAA regulations on electrical wire safety performance standards?
Mr. HEALING. I would like to say that we are making those recommendations to the FAA directly and through the working group that we have. We participate in the FAA and the ATA's committee, the ATSRAC; and we also participate heavily in the aging aircraft issues and conferences and symposiums that are going on. So in that way we do transmit to the FAA what our recommendations are.
Mrs. FOWLER. And you are in the process of doing that now?
Mr. HEALING. Yes. In fact, just next week there is an aging aircraft conference in Albuquerque and there will be at least three people from our office there. Along with ALPA and others, we are all going to be presenting the same type of information that we have discussed at the AWIGG meetings and also here.
Mrs. FOWLER. We would be interested in getting a copy of those recommendations, too, after you have released them to the FAA.
Mr. HEALING. We will see you get those.
Mrs. FOWLER. Thank you. Dr. Bruning, you have stated in your testimony that this aircraft wiring that we have some interesting samples of here, this noncomposite wiring has a limited service life.
What is the evidence that wiring can age quickly under certain environmental conditions? What have you been looking at?
Mr. BRUNING. We have two sources of information, one, the laboratory, which one always suspects may not represent real life; but then we also have many, many aircraft inspections, where we have found insulation of each of the types that are commonly used on an airplane have deteriorated under certain conditions. And we can correlate those deteriorations by theoretical calculations with the results that we see in the laboratory.
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So I can say that there is no one qualified in chemical thermodynamics, statistical mechanics, who has been willing to disagree with the kind of data we present over here on this chart, which was based on those kind of things.
Mrs. FOWLER. Thank you. Mr. Roberson, could you tell us, approximately, how much does composite wire add to the cost of a new aircraft compared to using the older types of wire when you are building a new aircraft?
Mr. ROBERSON. While there may be a slight increase, the relative costs are insignificant. For example, a $35 million aircraft would have approximately $3,500 worth of composite wire, whereas with the noncomposite wire it might be $2,800. So, again, it is insignificant, and I would submit a small price to pay for increased safety.
Mrs. FOWLER. So for these commercial aircraft builders to begin using all composite wire would add a very minuscule amount of the cost of a new plane?
Mr. ROBERSON. Correct.
Mrs. FOWLER. Could you tell me what types of aircraft are presently using this new composite wire coating, and is Boeing installing composite wire insulation in all of their aircraft?
Mr. ROBERSON. Boeing does use the composite wiring. They do not use it on all their aircraft; but they are using it, I believe, on the narrow body. I am not sure about all wide-body applications, but I know it is used on the narrow bodies.
Mrs. FOWLER. I think they are using it on all, I think we understand now. What about Airbus?
Mr. ROBERSON. I am not familiar with what Airbus is using at this point.
Mrs. FOWLER. Does anyone else on the panel have an answer to that? Do you know what Airbus is doing? And I commend Boeing. I understand they have gone to the new composite wiring on all their aircraft.
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Mr. BRUNING. I know Airbus is still using both straight aromatic polyimide and a TKT. I do not know the quantities.
Mrs. FOWLER. So even though it only costs a few thousand dollars per plane to go to the composite—.
Mr. BRUNING. This is not a matter of cost, Madam Chairman. It is a question of the engineering insight that I need the smoke resistance here, I need the high temperature tolerance there, so I use different wires, and then the expertise of the engineer in making the judgment.
Mrs. FOWLER. Knowledge of wire properties and how to use it. Thank you. Let me go to Mr. Oberstar.
Mr. OBERSTAR. Thank you, Madam Chair. I just want to get the overview of the members of the panel. Do you think there is a crisis in aircraft wiring?
Mr. BRUNING. Do you want me to start? I got home last night from the FAA aging aircraft test site at 1 a.m. in the morning. I was far more comfortable coming home on an American-flag airline than I would have been walking, driving, or any other travel means that you can come up with. Our airline industry is amazingly safe. But, like all Americans, we are always looking for improvements.
Mr. OBERSTAR. Any other of the panel disagree with that view?
Mr. HEALING. Mr. Oberstar, I just want to thank you for your continued long-term interest in aviation safety. We find it reassuring to have you and the other members here present supporting that very critical issue for us.
As to whether or not there is a crisis, I think what we are dealing with right here is exactly what is required to prevent a crisis. I think if we have any major concern, it is, for example in the Navy, it is the aging fleets of aircraft, many of which don't get replaced in the time that we thought they would be replaced in. So we are facing new challenges that were not anticipated in past years, and we are dealing with it up front.
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I think the most important part of it is that we are being proactive. We are sharing information. And I think based on that, we are going to move ahead smartly and prevent that crisis.
Mr. OBERSTAR. That is a very good answer, and thank you for your kind and thoughtful words.
It is important to establish that point, that airplanes are not about to fall out of the sky because wiring is bad. What we are facing here is the need for a holistic approach to maintenance of high-time aircraft, that is, aircraft that have in the range of 35,000 operations, lest we get to the point, which we learned a long time ago with the Aloha tragedy, where 18 feet ripped off the top of a Boeing 737 enroute to Honolulu. That shook the foundations of aviation safety specialists all across the world.
I will never forget the electric atmosphere in that hotel room where 400 specialists gathered from all over the world, airline technicians, pilots, Government aviation authorities. All were determined to understand the problem of aging aircraft, high-time aircraft. And I had been advocating a much advanced maintenance program before that tragedy, and people sort of thought it was pushing things a little too far. What we came out with was the Aging Aircraft Act of 1991 that focused on structures.
We understood that people, in the process of tearing down aircraft to bare metal and a new philosophy of inspect and replace, instead of inspect, detect and repair, that systems would also be evaluated and systems replaced. We did not emphasize that in the legislation. So with you we are going through this learning process. And I think what this panel is saying is, apply new ideas, apply new technology as you go along.
You do not have to go and pull out 100 miles of wire out of every aircraft in the fleet and replace them all, but recognize that there are different applications in different parts of the aircraft. Where there is heat, you need one type of wire; where there is cold, where there is moisture, another type of wire. But the four together, vibration, moisture, temperature, and location, are critical. And in the process of maintenance you have to address those issues, make upgrades as necessary, apply new technologies where they are proven to make an improvement, and to do so in the course of D-checks, and especially in the course of the aging aircraft maintenance.
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And if there is one area where I have real problem with the aging aircraft maintenance, it is permitting carriers to do rolling D-checks and kind of a rolling aging aircraft maintenance. I want that aircraft torn down all at one time. I want all that work done at one time. And if you are going to fly that aircraft 30 years, you are going to fly it beyond what you thought was its initial economic life-span, then make sure we don't have flying patchwork quilts.
I also want to compliment the Navy. I think the Navy has made extraordinary contributions to aviation safety because of its experience in flying aircraft in the most inhospitable and hostile of environments: salt air, inimical to the copper-aluminum sandwich of the aircraft hull and interiors. And the lessons the Navy has learned have been applied in many applications, many aspects of aviation manufacture and maintenance.
I do not have any real mind-stumper questions for you, I just appreciate the contributions each of you has made. And Captain McCarthy, in particular, I want to compliment ALPA on its splendid testimony here today. It was very well conceived, thought out, and presented.
Mr. MCCARTHY. Thank you.
Mrs. FOWLER. Thank you, Mr. Oberstar. Mr. Terry.
Mr. TERRY. Let me follow up on some of the comments that ranking member Oberstar had hit on. I saw some smiles and nodding of the heads, but I would like to get some of those answers actually on record.
As I was listening to all of your testimony, there seemed to be a common theme, and that theme is expressing the virtue of a new composite wiring. I interpret from your testimony that you were saying all new manufacture should have this type of wiring. And, Mr. Roberson, you pointed out the cost difference between the two is fairly minimal. But are any of you suggesting a certain level or a total retrofit of planes that are already in use?
That is to any of you. Are any of you advocating that position? Captain McCarthy.
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Mr. MCCARTHY. From the pilot's point of view, Mr. Terry, it is not, right now, so much a question of the wiring, from the pilot's point of view, as it is the protection should one of these faults occur. The difficulty, obviously, if we can prevent the wire from malfunctioning in the first place, arc tracking, call it what you may, we are well ahead of the game. And if we can do that by selective replacement or by new spec, we are way ahead of the game.
But where we can make some serious inroads, probably in a fairly short time, is by ensuring that what is not now protected—and that is what you have heard from all of us—circuit breakers that we have mounted in the cockpit will not protect against this type of fault.
Mr. TERRY. And that is my follow-up question, so if you would expand.
Mr. MCCARTHY. Yes. There may be a transfer of technology available from, quite frankly, the homeowner, or the home construction industry into the aviation industry, to give us technology that will allow us, if these occur, to prevent them from ballooning into something that we really cannot deal with in-flight. So that is the real issue.
The expensive and impractical way would probably be to replace 200 miles of wiring. You and I both know that is not going to happen. But if I can start to selectively go after the circuit breakers, and if I can look at how I route wiring so that if it does happen it's not going to bring the aircraft down, that is where we can make our money.
Mr. TERRY. Mr. Healing and Dr. Bruning, would you agree if on these planes we put in these smart circuit breakers, that would significantly reduce the risk of fire events on planes, without going so far as to demand retrofitting and new composite wiring?
Mr. HEALING. I don't think there is any question that the implementation of what's called the arc fault circuit interrupter, the AFCI technology, would make a significant inroad in the incidence of arcing and arc tracking that are currently not detected. The pilot flying the aircraft could get a very early warning when a single tick or a single arc goes off. And maybe the smart circuit breaker would not break the circuit and cut the power to that particular functionality, but maybe the circuit breaker would know that that arc had occurred and tell the pilot, inform the pilot, that this is something that may need maintenance and maybe needs watching right now.
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If we can employ the computer technology, the microchip technology that is available today, with the circuit breaker technology that is in your home, in your bathroom, to prevent you from being shocked, I believe, quite honestly, that this is probably the first and easiest step forward.
But this is not to say that we need to stop thinking about wire itself. The Navy's choice, in 1981, was to change its specification from what it had been previously using, but it did not in the same document say pull all the wires from the aircraft. We found that in some cases we did that and it was extremely expensive, which is probably the biggest reason not to do it as a wholesale thing but rather as a selective.
Mr. TERRY. Dr. Bruning.
Mr. BRUNING. I would like to remind us all that in the 1960s the electric utilities industry put a great deal of effort into ground fault arc detection systems. It turned out that, because there were four different kinds of arcing faults, it was not practical and possible to build an arc- detecting system. Now, the arc-detecting system we are working on today is pointed toward the developments of the type of arc that occurs in a bathroom or in a bedroom. That is one of four types of arcing.
So I would admonish the committee and our technical community, let us be real careful to look at all four types of arcing, not just ticking faults, not just teasing faults, not just carbon-arc faults, not just wet-arc faults, but all four of those. Let us not put a lot of new equipment on an aircraft that starts to show up one time in a thousand are causing a problem, because we have far fewer problems than one time in a thousand today.
Mr. TERRY. Thank you.
Mrs. FOWLER. Thank you, Mr. Terry. Mr. Traficant.
Mr. TRAFICANT. I appreciate those comments. That is one observation I was going to make. We have all these electrical perks on these planes with such sophisticated systems, do we have too much wiring? Maybe we need to simplify it rather than become more sophisticated in trying to detect. Maybe it is a combination of both; see how we can reduce the volume of wiring with a safety mechanism.
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I want to say to this panel that I was delighted when I heard Mr. Healing say to one question that he didn't quite have that one. I appreciate that. Then, when you talked about gathering evidence that supported a theory in coming to a reasonable conclusion about a problem that you suspected in the Navy, I think that is about where we are. And I think this is a tremendous panel that has informed us quite a bit.
I think these regulations have been on the book for a long time. They probably need to be updated. And I think your input and advice is going to have to be given to this committee. You know what has to be done. You have to educate us.
I have one brief question, and you can answer it yes or no. Are we getting enough commercial spin-off from our space program that deals with high-intensity heat and insulation of wiring? Are we getting that type of spin-off that our aviation industry is able to capitalize on the tremendous taxpayer investment of our space program? Mr. Healing.
Mr. HEALING. I believe we are.
Mr. TRAFICANT. Dr. Bruning.
Mr. BRUNING. I see substantial cross-feed.
Mr. TRAFICANT. Any other questions I have I will submit to the panel. Thank you.
Mrs. FOWLER. Thank you, Mr. Traficant. I want to welcome Congressman Doolittle from California, who is also a member of the subcommittee who has joined us. Do you have any questions of the panel or a statement you would like to make.
Mr. DOOLITTLE. No, but I appreciate the panel's being here.
Mrs. FOWLER. Thank you so much. If there are no further questions—.
Mr. TERRY. Madam Chairwoman, may I ask one further question?
Mrs. FOWLER. Yes.
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Mr. TERRY. I have to resort back to my lawyer training, I guess, and always ask one last question.
I am just curious. There is some criticism of inspection, visual inspection. Obviously, common sense tells us if you are talking about 150 miles of wiring, it is physically impossible. And with glasses, this is still even difficult 6 inches away.
What other techniques are available? Are there any other techniques available for inspection?
Mr. BRUNING. I'm in a very selfish position because, of course, I am pushing something that we have been working with for about 15 years.
I think the ability to make the calculation to predict when the wire is going to become so weak that it can no longer be expected to function practically is an extremely important thing. It is a management tool that can only be implemented at the top level.
Mr. TERRY. So there is no little machine that you can hook up, like when I take my car into the gas station?
Mr. BRUNING. There is a machine sold by a company in Kansas City, one in Ontario, California. We have a technique, which I mentioned briefly, our DelTest. Those ought to play out in the commercial Darwinian atmosphere. They should not be dictated by people who have not tried to face the practicalities of a maintenance department in an operating airline.
Mr. TERRY. Those techniques or machinery being used in the industry to test now? To inspect, I mean.
Mr. HEALING. The Navy has actually used that type of technology to develop our own plan for replacing selectively wires that seem to be in at-risk areas.
I would add a couple of comments: that everybody sitting at this table, the companies and organizations sitting at this table, plus the FAA and NTSB, are participating in the AWIGG group, and that is why we seem to sound alike on certain matters. I believe we are communicating much better than we ever did in the past, and it is that fact that I believe is going to put us in a proactive position to make these improvements.
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With respect to the inspection question, there are emerging technologies, and that was what I alluded to earlier that need to be perfected. And for the people who are concerned about how long it might take to do an inspection or how destructive or nondestructive it is, it would be very important to focus on those things that are not destructive, that do not take a long time, but that are very, very reliable. And there are two or three things coming along that we believe need to be pushed a little bit harder, if we can, so that we can use them.
Mr. TERRY. Thank you.
Mrs. FOWLER. If there are no further questions, then I want to thank the members of this panel for giving so much of your time and for your comprehensive testimony, because you have shared a lot of information and ideas with us that are going to be very useful to this subcommittee. So thank you again.
We do have a vote on. So if I can encourage the Members to go vote quickly and come back, then we will start right away with panel three, Mr. McSweeny. So we will go vote and come right back. I think this is going to be the last vote, I understand, of the day.
The subcommittee is in recess.
[Recess.]
Mrs. FOWLER. Would the subcommittee come back to order. We've had a little change in procedures over on the floor, so I want to apologize for the delay. We ended up with two votes and also had an announcement on the floor that they were—that was the last vote until next Tuesday because of the storm that's coming in tonight or in the morning. They wanted Members to be able to get to their districts, those who have airports open, mine isn't, but for those who do. So we've had a total change.
Mr. Traficant was going ahead to catch his plane. Mr. Oberstar is here and a couple of our members might be back. But we thought in deference to you, you have taken your time to be here we wanted to proceed with the hearing, while trying to get others out. Those who have to catch planes tonight or early in the morning can do so.
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I want to officially call the third panel, representing the Federal Aviation Administration. Mr. Tom McSweeny is Associate Administrator for Regulation and Certification for the Federal Aviation Administration. Accompanying Mr. McSweeny is Ms. Elizabeth Erickson, Director of the Office of Aircraft Certification Service.
I want to welcome you both and I also want to thank you, Mr. McSweeny, because I know you rearranged your schedule to be here for this hearing today. I didn't want to have to change it again. I appreciate your doing this.
If you would both just please stand and raise your right hand, even though I know it's in a cast right now.
[Witnesses sworn.]
Mrs. FOWLER. Thank you. If you could be seated.
Mr. McSweeny, I ask you if you could summarize your testimony in 5 minutes and, without objection, your full written statement will be made a part of the record.
And I want to thank you, we met earlier last week, I appreciate your taking the time to do that. It was very helpful. Thank you.
TESTIMONY OF THOMAS McSWEENY, ASSOCIATE ADMINISTRATOR FOR REGULATION AND CERTIFICATION, FEDERAL AVIATION ADMINISTRATION, ACCOMPANIED BY ELIZABETH ERIKSON, DIRECTOR, OFFICE OF AIRCRAFT CERTIFICATION SERVICE
Mr. MCSWEENY. Madam Chair, I thank you for those comments. Again, I want to apologize for not having the typical suit and tie, but there's just so much you can do with a cast on your right hand, or can't do.
We have really looked at wiring over the years. In
the—in the early 80s when Kapton was introduced and people started seeing problems, we really focused on it deeply. We spent efforts with the manufacturers, looked at it. We created a program at the Tech Center to look at it. We've had lots of employees over the years looking at wiring. So we've really focused on it as an issue kind of at the beginning because of our requirements to oversee the safety of any product that's out there in service.
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But the Gore Commission kind of did a couple of things. First of all, it raised the safety bar. It said, you know, you ought to be looking 10 years out and you ought to be aiming at a five-fold reduction in accidents. We believe that's an appropriate goal for us. We have it in the Agency. I have it in my performance standards.
In that vein, they also recommend today looking at wiring. We think that was a very appropriate recommendation because while we may not have had a large indication of safety problems up to that point, we really need to make sure that problems don't get introduced as the airplanes age. As a result of the, Gore Commission recommendations in February of '97, that the FAA form a study team. That study team was headed by Dr. Greg Dunn, who works out in our Seattle office. It was a 1-year study to look at all the aging issues, wiring and systems and hydraulics and pneumatics in all of the airplane.
They did detailed inspections of four aircraft with the manufacturers present. We met—the team met with FAA inspectors who are out there every day looking at aircraft, to gain their insight as to what some of the issues might be that we should look at. They met with Boeing designers and talked about design issues. They met with Boeing maintenance people and talked about maintenance issues. They met with wiring manufacturers and met with other experts in the area.
And their recommendations were presented to me at the time I had Beth Erickson's job in July of 1998, and what they said was there was really no immediate safety concern that we should take immediate corrective action through airworthiness directives or something like that. But in all honesty, they did identify discrepancies, some of which the Board has also discovered in their wiring inspections and said we really need to focus on it if we want to maintain safety as it is, or improve safety. And we think that's entirely appropriate.
From that we created the Aging Transport System Regulatory Advisory Committee, ATSRAC. That committee is taking the Greg Dunn recommendations and turning them into action. There's a large involvement with the industry and the military. I was looking over an agenda of a recent meeting; there were 55 industry, FAA and other government people at this one meeting. Just to summarize a little bit, there were 13 Navy people there, one from the Air Force, three wiring manufacturers present, six FAA employees, three people from Electromech which has really been supporting this, three people from the NTSB.
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So basically the people, in the first panel that were testifying earlier, are all a part of our program. Not just on the larger committees, but down there in the working groups were the real activity is being done.
What ATSRAC has put together is a program that you see on the chart up here to my left. It is a program that starts with three basic issues in the rectangle there: fleet sampling inspections, service data review, and research and development. And this program pretty much parallels what we have done in the structures, Aging Structures Program, but where there are unique things, we have been smart enough to realize we don't want to do that exactly the same.
Fleet sampling, in addition to the four airplanes that Dr. Dunn looked at, this ATSRAC group has looked at 71 different airplanes, every model except the L-1011—well, not every model but the aging ones, the DC-8, the DC-9, the DC-10, the 727, -37, -47 and the Airbus A-300. So we've got 71 aircraft inspections behind us.
We are working as we speak down at Sandia in Albuquerque, New Mexico, with the 747 that we were able to purchase with all the systems in it; and we're developing techniques with this ATSRAC group on how we will do what we call intrusive inspections. How will we go out and look at wiring, take bundles apart and things like that in aircraft that are made available to us. We think over the next 6 months we will be able to reach about six or eight airplanes that are taken out of service and really look at the stuff that you can't look at visually.
It contains a research program. We're talking about the circuit breakers in that research program. The elements of the program itself are corrective actions. Just an example, on the 747, as a result of TWA Flight 800, we've taken 19 corrective actions or proposed 19 actions dealing with wiring alone, another four with other systems. We've addressed problems on the MD-11 that we've seen. We've addressed problems on wires and fuel tanks.
And if you remember, back to Mother's Day a year and a half ago, there were 737's on the ground because of some of our airworthiness directives.
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The program is going to improve inspection and maintenance practices. It's going to look at design practices. Some of the stuff is already coming out: new specs from ATA on inspection and maintenance; videos for their inspectors. We're going to look at improving data reporting so we really can track down what the wiring issues are when we see them in the future. And we're developing training; we've already developed parts of the training. That's—using Mr. Oberstar's word, that's a holistic approach to the whole problem. We think it's a great program. We think the right people are in it. As we learn, we're probably going to make changes to it.
And with that, I finish my opening remarks and we're prepared to answer any questions you might have.
Mrs. FOWLER. Thank you, Mr. McSweeny. I welcome back Mr. Doolittle also. Thank you. I think we have all of us.
I just have a few questions. I think we have all agreed from the testimony here today, and I want to make sure you agree, that the noncomposite wiring that is used on aircraft today does have a service life limit.
Mr. MCSWEENY. I would have to be honest and say I don't necessarily agree with that. I think that is still undecided. I think if you were to ask people like Mr. Bruning, he would probably say the same thing. In fact, he has said that to us in some of his correspondence.
I think the issue is that we have to be open minded. And if we find evidence through this ATSRAC program or any other program that we do have to put a life limit on it, that's the time to make that decision. And we—right now, I think the key is, we're gathering data to make a data-driven decision and to keep our eyes wide open.
Mrs. FOWLER. Would you agree there was a comment—I forget, maybe it was Mr. DeLisi, used a figure that was roughly about—over 80 percent of the traveling public are now flying on aircraft that primarily are wired with noncomposite wiring. Was that a correct figure?
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I want to check with you. He said about 12 to 13 percent of the planes currently have the composite.
Mr. MCSWEENY. Our numbers are around that range. We have looked at which wirings are in which percentage of airplanes.
Mrs. FOWLER. So he was on the right track. Okay. I want to commend you for the different groups that you all have formed that are doing these studies, the Aging Nonstructural Systems Study and the Aging Transport System Study and the Rulemaking Advisory Committee.
Could you tell us what type of timetable or deadlines they're operating on, as to when do you expect results? You mentioned a little earlier in your statement something about 6 months. What sort of time frame before these groups will be taking some type of action.
Mr. MCSWEENY. From the ATSRAC, the Aging Systems Program, there are products coming out already. As I mentioned, the ATA spec is being revised. We've issued airworthiness directives where we've seen necessity. Videos have been created. We finished a part of the development of a training program for engineers, and we're working on the maintenance area. Products are coming out of this group as it moves forward.
Except for maybe the longer-term research and development, most of the products are going to be finished in the 2001 time frame. So we're not talking about a real long program here.
Mrs. FOWLER. I want to make sure now—one of the things we've all sort of agreed on is that aircraft maintenance procedures need to be changed. How long is it going to take to develop and disseminate new training course materials on aircraft electrical system safety for maintenance workers? It isn't going to take until 2001, is it?
Mr. MCSWEENY. Let me speak to part of it and Ms. Erickson can maybe add to it.
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When we developed the Greg Dunn study, and it was finished and I saw the recommendations, I said there's a lot of good meat in there. We shouldn't wait until we form an advisory committee in the area of inspections.
So we got together with the Air Transport Association and in 30 days we developed a revision to their specification 117 that deals with how to do maintenance inspections. So we immediately did something there.
What we're doing now is taking more knowledge that we learned and we're moving it into more and more training.
Mrs. FOWLER. So that's just going to be a gradual process. As you learn it, you will disseminate it, rather than saying by such and such a date we will have a new training system in place.
Mr. MCSWEENY. That's correct. As we learn things that are important, we have seen a strong desire by the industry to get it out into the system so it can be worked on.
I don't know, Beth, if you want to add to that.
Ms. ERICKSON. The only thing I would add is that in the same time frame that they were doing the development of the new spec 117, which has better maintenance practices defined, the ATA also developed a video which is very helpful for maintenance technicians that work for the airlines, that does things like actually visually demonstrating safer maintenance practices than some that may be used right now. So instead of waiting until a date certain that we're going to have a training program, we're taking a different approach, which is, as we find it out, let's get it out now and get it adopted as quickly as possible.
Mrs. FOWLER. I commend you for that, because I think the sooner they can have the new information, the better. So thank you.
Speaking of regulations, in going through some of my reading on this, the electrical wire flammability requirements that were defined in FAR Part 25, Appendix F, were written over 20 years ago. Do you believe that these regulations should be rewritten to adequately address critical safety issues such as smoke generation, electrical arc tracking, et cetera; and if so, what time frame are we looking at with that?
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Mr. MCSWEENY. I think if you look at the area of arc tracking and some of the things that are going to probably come out of that, it makes sense to say that we would probably do something in the area of new standards for arc tracking. Whether we believe we should go back and rewrite the generic standards that we have—and our standards are very generic to allow development—whether we want to rewrite those to talk about smoke. And the wire might be a function of how successful the arc tracking circuit breakers might be. So that issue, I would be a little more open on and say that I think that awaits some of the work we've done.
If I could, with one quick prop, I know the questions were asked earlier about the arc breaking circuit breakers. This is a circuit breaker that you can put in your house that has arc tracking capabilities. I think Dr. Bruning was right on to say there's more than one kind of arc tracking, and you have to be careful.
But this is an aircraft circuit breaker. And the key is to get this technology into this size. And there's a lot of work being done; the Navy is spearheading some stuff, and we're putting some money into that program. There's a lot of people out there in their own companies trying to do that.
We just—for instance, we're walking around Oshkosh during the air show and ran into a booth where there's a German company that makes circuit breakers, sells them to U.S. Boeing and other companies and sells them to Airbus. He believes he's very close to having a double-trip breaker where you can maybe have a caution light that the pilot can see that something is happening, look at it the next maintenance interview, and then a quick acting one.
It's likely to take a few years to really get the technology down into this size, but I think when he does, it's really going to beg the question of why can't we put it in older airplanes.
Mrs. FOWLER. One last question, again looking at time frames I—when you use 2001, is that the time frame that you're looking at for the Aging Transport Systems Rulemaking Advisory System Committee, so—for the record, I have to get the whole name out there—but to complete their new regulations covering aircraft wiring? Are we looking at not being able, until 2001, to get that?
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Mr. MCSWEENY. Well, the plan we have shows activities completing in 2001, and as Beth and I both said, there's a lot of stuff we're going to roll out in the interim. If we decide to do rulemaking for whatever reason, it might extend beyond that time. It just depends on when we decide to do it. It could be, you know, right at the end of the program, we decide we want to issue a rule. Certainly we wouldn't get that out by 2001.
Mrs. FOWLER. Could you submit the plan for the record?
Mr. MCSWEENY. The schedule? Yes, we'll be glad to.
[The information follows:]
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Mrs. FOWLER. That would help. Because I think as we all agree, the sooner, the better, if there is a need, rather than waiting till 2001, which is a considerably lengthy time frame to get these in place. Thank you.
I'll defer now to Mr. Oberstar.
Mr. OBERSTAR. Thank you, Madam Chair. I want to compliment Assistant Administrator McSweeny for his long-term association with this aging aircraft issue. You were there at the very first conference with Tony Broderick; in fact, Tony credits you with setting it all up, as he said, doing all the heavy lifting to put that conference in place. That moment is etched in my mind, as I described earlier, the crackling atmosphere, expectation of people there, sensing that they're on a verge of a new frontier, this aircraft maintenance and safety, and taking bold steps. And the FAA took some strong steps forward at that time and has continued to do so.
The previous witness for ALPA suggested evaluating and possibly incorporating fiberoptics, look at his testimony, not all the systems in aircraft need wires for signal and fiberoptics as the light signal carrier. And it suggests some candidates for this type of technology.
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Have you given that some thought? What's your reaction to it?
Mr. MCSWEENY. Yes, fiberoptics has been something that's been really studied and has been studied over the years. McDonnell Douglas, before they were incorporated and under Boeing, did a lot of work in the fiberoptics area. My key issue on fiberoptics is, we've got to make sure that we can show that it performs well even with its failure modes, which you kind of have to work through and identify to at least the level of safety we have out there now. And we really have across aviation a level of safety that's in the 1 per 100 million or getting close to 1 in a billion. I mean, just 15 months ago or so we moved a billion passengers in commercial aviation without a single death. We need to make sure that fiberoptics, if it gets in—and it does have some promise—is at least as good as that, because that's the safety that's out there right now. That's a tough challenge.
Mr. OBERSTAR. There are very different standards for safety aboard aircraft than transmitting data and voice over fiberoptic cable. And in an environment where that cable is relatively undisturbed, it's in one state and status and being on board aircraft, subjected to a variety of pressures that we all know occur in that environment, including moisture and vibration and exposure to other materials and textures, that's good to continue reviewing it.
I was intrigued with the response of the previous panel. I said, is there a wiring crisis? No one believes there is a wiring crisis. There are incremental steps that we can take to improve the status and quality of wiring.
One of the things that you and I have discussed previously is the need for much greater care in maintenance.
There is evidence from previous accidents, or incidents, of insulation scraped off the wire by a screwdriver as a mechanic was moving wire through a stringer in the interior of the aircraft and giving it a little nudge with this screwdriver, incidentally scraped off a little insulation. Now you've created a problem. And then if there are flammable materials or if there is a subject nearby where arcing can occur, it will.
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Has FAA reviewed maintenance practices with regard to wiring and issuing cautionary notes about taking greater care in this environment, avoiding the bundling, providing insulation for wires that go through stringers to prevent their chafing, taking care about metal shavings that occur when other work is done on the interior of an aircraft, major maintenance overhauls, so that the shavings don't go down and get on the wires and become, in and of themselves, a source of shorting or ignition, melting?
Mr. MCSWEENY. That clearly is something that needs to be done. Let me ask Beth Erickson if she would add some, because she's far more knowledgeable of what ATSRAC is doing in that area.
Ms. ERICKSON. Congressman Oberstar, as you pointed out, many of the things that we have found in our inspection programs to date have pointed out that across the various types of wire, the main issues really are design, how the wires are installed, whether the bend radiuses are too tight, whether the clamps are holding them in place for the vibration kinds of issues, whether they're routed so they don't get fluid from lavatories dripped on them. And then also in the maintenance area, you've pointed out several problems that could occur.
I think that through the inspections that we have done, the first step in trying to make those improvements has already occurred, that is, the awareness and the education that has been spread throughout the industry has already started. That that's really the problem that we need to address, the design issues and the maintenance issues.
The committee is set up to produce products in both of those areas. We've already done, as Mr. McSweeny pointed out, the improved maintenance practices through the spec 117, and we will be revising and updating that. We're developing training for our engineers in my organization so that when they're approving designs, they're going to be looking out for the best design practices. And when modifications are done, which is, I think, the example you were giving with the mechanic accidentally shaving off that insulation, that occurred during a modification; and so we're going to be making sure that in maintenance modification activities that those lessons learned are addressed as well.
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So we're addressing it on all fronts. And products will be produced that will train not only the maintenance inspectors, but the actual maintenance workers and our engineers so they know what to look for.
Mr. OBERSTAR. Thank you, Beth. Let me compliment you for your grasp of the subject matter. You have always been responsive and knowledgeable of the subjects, and you're a great asset to aviation.
Ms. ERICKSON. Thank you.
Mr. OBERSTAR. At the time of the aging aircraft 15-year intensive tear-down and overhaul of aircraft, have you contemplated requiring replacement of wiring systems at the same time?
Mr. MCSWEENY. My recollection, thinking back to that conference in '88, was that there was a break-out session on systems and wiring. The conclusion that we made in that program at the time was that the structural issues were far more important.
We also had a panel on engines and aging engines and things like that, and we concluded that there was so much work to be done in the aircraft structure, that that should have our highest priority. And over the years we've issued airworthiness directives that have resulted in over a billion dollars of modifications to the fleet of aircraft out there.
I think that program is moving—continues to move forward. I think now is the time to expand it, as the Gore Commission said, to expand it to look at the aging wiring, aging systems.
Mr. OBERSTAR. You're not contemplating now requiring replacement of wiring systems, but it's a matter you will—the FAA will more intensively review.
Mr. MCSWEENY. We have a very open mind on that issue right now. And I think the—it's a matter of what does the data show us.
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Mr. OBERSTAR. You can't pull some wires out of a bundle. I think you have to either replace the whole bundle or not, because—.
Mr. MCSWEENY. We do not recommend—.
Mr. OBERSTAR. —you can disturb other parts.
Mr. MCSWEENY. Yes. Excuse me for interrupting.
We do not recommend pulling wires out of bundles because you disturb the rest of the wires that are in there, and you could cause a really serious problem.
Mr. OBERSTAR. Final comment: Going back to TWA 800, the question was raised earlier in the hearing, and perhaps left somewhat open by Dr. Loeb's response; and that is that the issue is still unresolved by the Board on the matter of probable cause and the condition of the center wing tank fuel level, temperature level and potential arcing that may have ignited the tank.
What are FAA's views on that matter at this stage?
Are you prepared to recommend that the center wing tank be loaded with fuel, the fuel up above the scavenge pumps above the wiring level, maintain certain temperature, protecting that tank against overheating because of the air conditioning packs or under certain weather conditions?
Mr. MCSWEENY. Well, from TWA, we're really looking at three things. We're looking at what may have caused an explosion, electrically. Static-wise is there anything in there that could have caused an explosion? How do we deal with the flammable mixture that's in the fuel tank? And that's either, do you want to inert, to get rid of the oxygen, or do you want to reduce the temperature so you don't have a flammable mixture? Any fuel, if you cool it down beyond a given point—and that given point varies with each fuel—you reach a condition that is nonexplosive.
We will be issuing fairly soon a notice of proposed rulemaking to really deal with the issue of reducing the probability and the exposure of fuel tanks to conditions that could cause explosions, and that includes temperature in the tank. We will be looking for comments from the industry on what's the best way of doing that. We think it's appropriate, because we really don't know the cause of that accident yet, it's really appropriate to deal with all three elements of the fuel triangle—ignition, fuel and—see, I forgot the other one. Oxygen, yes. Oxygen, ignition and fuel, we're looking at all three, because it's probably a combination of things that's going to give us the right kind of increase in safety rather than focusing on just one.
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And we're really looking at this issue of center fuel tanks. We, as yet, have not supported the theory of just putting extra fuel in the tank, although we have required it in some cases because of some fuel pump failure modes, that we don't want the fuel to be pumped out below that pump until some other fixes are made. If you do add a spark, either a mechanically caused spark or an electrically caused spark in the fuel tank, if it's under the fuel level you can't generate enough heat and energy to actually ignite the liquid. It's only the vapor that's really the issue.
Mr. OBERSTAR. Thank you very much for the thoughtful response and for the very careful and thoughtful approach to that issue. We look forward—.
Mr. MCSWEENY. I appreciate your comments earlier.
Mrs. FOWLER. Thank you, Mr. Oberstar.
Mr. Doolittle, any questions?
Mr. DOOLITTLE. Mr. McSweeny, what has the FAA learned from past disasters that has highlighted the electrical system's problems?
Mr. MCSWEENY. I think we've seen in some instances in-service arcing that has gone undetected. We haven't seen it causing disasters and accidents, which is why we really do support strongly this issue of these new circuit breakers.
When we did our—.
Mr. DOOLITTLE. Excuse me. By the ''new'' ones, do you mean the little ones or the ones—.
Mr. MCSWEENY. We want to get it down do this size.
Mr. DOOLITTLE. But those don't exist yet, right?
Mr. MCSWEENY. But within a few years we think the technology and research will develop it.
We also, from the work we've done—as I mentioned before, within the group, Dr. Dunn's study, have seen things that we want to improve in maintenance and even in the design and production of these aircraft, to keep things that could cause safety problems out from the wiring. And whenever we see a problem in service, we are not reluctant to issue worthiness directives to require either immediate action or some action over a few months to correct a problem.
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Mr. DOOLITTLE. I got here late, and this may have been addressed in an earlier panel, but these aircraft can be quite old that are still deemed to be flight-worthy; is that true?
Mr. MCSWEENY. Some of the aircraft, 25 to 30 years old, yes.
Mr. DOOLITTLE. And as long as they pass your inspection criteria, the actual age of the aircraft is irrelevant; is that right?
Mr. MCSWEENY. As long as the aircraft are properly maintained and properly repaired, and aging is properly accounted for, we think, at least presently, that life may not be an issue. We're still open-minded on that relative to wiring and systems.
In the structures area, our criteria really for the Aging Structures Program was that if properly maintained and material replacement, which means certain aging structure had to be taken out and new structure put in, we created a program where life was not a safety issue.
We need to make that determination yet in the systems and the wiring area.
Mr. DOOLITTLE. What proactive steps is FAA taking to utilize test data to improve electrical system safety?
Mr. MCSWEENY. I guess I'm not sure what kind of test data you might be talking about.
Mr. DOOLITTLE. I guess any modeling that might have been done or, you know, indicators that would be a measure perhaps of the condition of the wiring.
Mr. MCSWEENY. Okay. We have this facility down at Sandia in New Mexico, and it started because of the Aging Structures Program, and it gave us an opportunity to use new techniques, new inspection techniques, new inspection equipment, and test it out on real aircraft.
With the 747 we have down there now, with all the wiring in it, we literally are going to use that as a test bed. And when people present new methodologies and techniques to us to inspect wiring, you can find out the condition of the bundle without taking it apart and all that stuff. We're going to use that facility and maybe others to really be the test bed. And if it can be done, then we think we've got something there.
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Mr. DOOLITTLE. And the acquisition of a 747 is just within the last year or two?
Ms. ERICKSON. I can't remember exactly when it was purchased, but we have it fairly—we've gotten it in just the last few months.
Mr. DOOLITTLE. Okay. So that, you think, will be a significant tool in helping to improve the overall safety of these mechanisms?
Mr. MCSWEENY. That's correct. That kind of a technique has really proven out in the Aging Structures Program.
Mr. DOOLITTLE. Thank you very much.
Mrs. FOWLER. Thank you.
I want to thank you, Mr. McSweeny and Miss Erickson, for your testimony today for all the help I know you've been providing to this subcommittee and for the good work you're doing. We look forward to continuing to work with you. We are going to use the ideas and information that you shared with us. So I want to thank all the witnesses for their testimony today. We've heard a lot of good recommendations from the witnesses. I want to thank them for the time and effort they put in to being here.
I hope you can all catch planes out tonight, those of you that have to.
I just want to make a couple of comments in closing. The modern passenger jet is truly one of the great technological achievements of this century. Most of us that fly every week take it for granted that these giant aircraft that fly at 40,000 feet and travel at over 600 miles an hour, carrying hundreds of passengers and cargo around the world, you know, we just take them for granted.
In addition, it's one of the safest ways to travel. And I do want to stress that, as has been stressed earlier today too.
But I do believe, as I think everyone here does, that we need to continue to use every means available to us to improve upon the safety record. And that's why we're all here that's what we're all working on. So today I do believe there is room, as I think we all do, for improvement in aircraft electrical systems safety; and that subject deserves more of our attention just as you are going to be giving it a lot more attention from the FAA and some of our witnesses.
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We intend to continue to work closely with the Aviation Subcommittee in following the development and possible application of technology and information that could lead us to safer electrical systems. In our oversight capacity, we will be following the FAA's progress in developing and meeting the milestones, some of which we discussed today.
We're specifically interested, as I mentioned earlier, in the areas of maintenance training and the application of any new technologies as soon as we develop those new technologies. Because, we believe, these are important elements in the further development of our goals for the FAA's aging nonstructural systems plan.
We are also going to be contacting the Department of Transportation's Office of Inspector General, asking them to examine the procedures that the FAA uses to evaluate new technologies and the funding of those new technologies. There have been some questions raised that we didn't have time to get into today—we may at a later date—and this comes to the Congress too: Are we funding the research and development into new technologies at the rate we should be doing? That's a question we need to all be looking at, and should we be doing something different with that?
And then finally, too, we're going to have some follow-up questions for you also. The NTSB has carefully avoided speculation, and I agree they should have, on the possible causes of either the TWA 800 or the Swissair 111 crash. At the conclusion of these investigations into these tragedies, then we'll know whether these accidents should be added to the long list of electrical systems incidents or not.
But regardless of the outcomes of those investigations, we need as we all agree, to pursue improvements in the area of electrical safety which right now appears to be maybe the weakest link in our airline safety efforts.
So I want to thank each of you again for your participation. We look forward to working with you as we continue to keep traveling on our airlines, the safest means of travel.
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So again, thank you very much, and this meeting is adjourned. Thank you.
[Whereupon, at 5:10 p.m., the subcommittee was adjourned.]
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