Online NewsHour: Safer Skies, 737's Rudder Problem -- February 21, 1997

ELIZABETH FARNSWORTH: The National Transportation Safety Board has determined the Boeing 737, the nation's most widely used airplane, is not as safe as once believed. The NTSB has been testing the rudders of the 737, and yesterday the Board announced its conclusions. The rudder system on the popular jetliner does not provide the same level of safety as ruder systems on other kinds of passenger planes, and a malfunction of the rudder can no longer be considered an extremely improbable or extremely remote event, thus raising serious questions about whether the aircraft should be certified as safe. The Transportation Safety Board does not have the power to regulate and can only make recommendations to the Federal Aviation Administration. Yesterday, the FAA disputed the NTSB's findings, saying the 737 has a very good safety record. Boeing, the manufacturer of the 737's, also disagreed with the charges. A spokesman called the airline "absolutely safe."

SPOKESMAN: Our safety record speaks for itself. It's better than the industry average.

ELIZABETH FARNSWORTH: The Safety Board began testing the rudder systems as part of an investigation into two deadly accidents. In 1991 a United 737 went down near Colorado Springs, killing 25 people, and in 1994, a USAir flight crashed outside of Pittsburgh, killing all 132 people on board. In both crashes the planes apparently rolled out of control and crashed to the ground as they approached an airport in clear weather. The rudder immediately became suspect. Last month Vice President Al Gore announced the FAA would order airlines to install new rudders in all 737's within two years, but the clock hasn't started running on that deadline yet. Boeing is still designing the new system. In yesterday's letter to the FAA, NTSB Board members wrote they are concerned about the delay and recommended expeditious installation of the new systems. The letter also recommended pilots be trained in effectively dealing with sudden, uncommanded rudder movements.

ELIZABETH FARNSWORTH: And joining us now to discuss safety and the 737 are Charlie Higgins, Vice President of Airplane Safety and Performance for Boeing, and Jim Burnett, former Chairman of the National Transportation Safety Board. Thank you for being with us. Mr. Burnett, you were at the NTSB in 1991 when the Colorado Springs crash occurred and you had some concerns then about the rudder. What was the basis of those concerns, and what's changed since then to make the NTSB come out with such sharp language yesterday?

JIM BURNETT, Former NTSB Chairman: (Nashville) Well, I think initially we realized that one of the possible explanations for the Colorado Springs accident was a, a rudder control problem. No one at that time, though, had an explanation for the exact scenario that might be involved. Since then, the Safety Board has done testing, and, of course, pursuing the accident investigation in Pittsburgh and the plane upset at Richmond involving another 737--

JIM BURNETT: Well, there was another plane, a 737, that was upset last year, and it did recover and did not crash. But, of course, that's a very serious event.

JIM BURNETT: Turned over. And the rudder control system is suspected in all of those. The Safety Board and Boeing now have done tests which I think shows how that could possibly take place involving a jamming of a--of the control system, and that resulting in a reversal of the control forces. In other words, if you put in a left rudder input, you'll get right, perhaps hard right, and it's very hard to train pilots to fly, and the control inputs are opposite of what they're supposed to be. So there's a very serious situation there, and when you have three upsets occurring on the--in a 63-month period, a delay of 24 months or 30 months in getting the corrections in place is real dicey.

ELIZABETH FARNSWORTH: Mr. Higgins, continuing with some background here, Boeing has known for sometime that there might be a problem with the rudder, right?

CHARLIE HIGGINS, Boeing: (Seattle) Well, I wouldn't say that we've known for some time that there's a specific problem like's been alluded to by Mr. Burnett. We've had reports of some upsets throughout the history of the airplane, and with the data we've gotten recently from the flight recorders we've determined that most of those upsets throughout history have been due to either turbulence, auto pilot malfunctions, or yaw damper malfunctions. Now, what Mr. Burnett alluded to is something that's just recently been discovered through one of the tests that we did with the NTSB, where he described a rudder reversal that could occur. We have determined that under some very unusual circumstances a rudder reversal can occur, but there's no evidence to suggest in any of the accidents or the incidents that any kind of rudder reversal occurred. In fact, in the East Winds incident that he referred to--

CHARLIE HIGGINS: That's correct. And the one that he referred to with the flight recorder analysis that's completed to date, it looks like there was a mis-rigged rudder and a yaw damper malfunction that caused that. And it was nowhere near a hard-over condition at all.

ELIZABETH FARNSWORTH: Okay. Let's get this clear. So, Mr. Higgins, you're saying there is no evidence--the NTSB is not even asserting there's evidence yet to say definitively that rudder control problems caused the two crashes or the incident where the plane turned over landing at Richmond.

ELIZABETH FARNSWORTH: All right. Let me just get this clear now with Mr. Burnett. Is that true, Mr. Burnett, or is that as you--how you understand it?

JIM BURNETT: Well, as of yet, the Safety Board has not determined the probable cause of the two accidents or the incident; however, I think this is moving from a situation that's unsolved toward one that can be determined by the Safety Board, and I would hope the Safety Board would move forward with an official determination soon. In the meantime, Boeing has already agreed to finance the retrofit of the airplanes. They are in the process of making a new design, and the issue is how fast--how quickly that's going to be implemented.

ELIZABETH FARNSWORTH: And what did you think of the recommendations the NTSB made in that regard?

JIM BURNETT: Well, I agree with the NTSB if what they mean is that when each retrofit rolled off the production line at Boeing it will be immediately installed in an airplane, so that we won't have any shelf time for any of the retrofits. You can't do any better than that, and I certainly don't think that we need to press Boeing to put in service a retrofit that hasn't been adequately designed, but once they are being produced, the air carrier industry needs to be required to install them as quickly as possible and not have any operational delays in doing that.

ELIZABETH FARNSWORTH: Mr. Higgins, what did you think of the NTSB recommendations that this basically be sped up a bit, or that there not be any further delay?

CHARLIE HIGGINS: Well, I think that there's been some misunderstanding perhaps about the speed at which this can be accomplished. We first discovered we might potentially have an issue about the middle of October. We confirmed that I think the 29th of October.

ELIZABETH FARNSWORTH: You mean, you first figured--you first learned from the test that there might be a problem?

CHARLIE HIGGINS: We confirmed that on the 29th of October. We discussed it with the FAA immediately after that. We made our formal proposal to the FAA on the either the 31st or the 1st of November. They concurred that what we should do is do some additional testing and come back in a month with a recommendation as to what the final fix would be. The testing I'm alluding to is go out and check the fleet to see if there was any evidence of any secondary slide failures in the PCU. This is the problem that was discovered.

CHARLIE HIGGINS: That's correct. And we discovered in checking the 2500 airplanes in the fleet that there were no problems; that there no failures that had been undetected. From that point in time we spent about a month firming up a design solution for the rudder power control unit. We notified the FAA of our solution. They considered that for sometime, and then by about mid January, there was a discussion with Vice President Gore, the NTSB, and FAA, and that resulted in Vice President Gore announcing the package of changes that we were going to implement. We're hard at work on that package of changes. We'll get the first test units in early this spring. We'll get the testing accomplished, we hope, by mid summer, at which point we can put them on the production airplanes and begin retrofitting. And as soon as we can get these rudder PCU's out into the fleet, they will certainly be installed by the airlines.

JIM BURNETT: Well, I think the Safety Board is concerned about keeping that schedule. To some degree the Safety Board is running, I think, on the parade that Vice President Gore initiated here, and I think no one--everyone wants to see the solution implemented as quickly as possible, but there's concern about giving the airlines an arbitrary two years after the fix has been identified, and the equipment, the retrofit is available to do that. I think that they ought to--to be placing them in service just as soon as they are available, and ought not to be permitted to delay that for their operational reasons.

CHARLIE HIGGINS: In fact, that's what the plan is. As soon as the units can be produced, they will be put into the fleet, and the two years is a compliance period for the total fleet. And there's 1100 airplanes approximately in the U.S. and about 800--I'm sorry--1700 throughout the rest of the world--gives a total fleet of 2800 airplanes. So it's a matter of it takes time to get the units produced, manufactured, and out into the field. And the two years is the compliance period for the entire fleet. And so as soon as a unit is manufactured, it will be installed on an airplane.

ELIZABETH FARNSWORTH: Mr. Burnett, meanwhile, there are these worries about the power control unit that deals--that makes the rudder function. What should a flier--one of our viewers who may be scheduled to get on a 737 tomorrow--make of the difference in views here? What should a viewer who flies think?

JIM BURNETT: Well, we are in a race to get these things implemented before we have another accident. That is my view, and I have flown the 737's since I've known and been aware of these problems. But I've also made alternate flight decisions, and it's really how important it is to use aviation to keep your schedule. So I think it's something that the viewers and people who are consumers of aviation services need to be concerned about. It is--I don't think that grounding the 737 fleet would be in the public interest, but retrofitting it as quickly as possible certainly is a necessity, and we need to try to do that before we lose another plane.

ELIZABETH FARNSWORTH: And also to you, Mr. Burnett, the--and NTSB also recommended that pilots be trained to deal with this strange rudder phenomenon that can occur. Do you think they can compensate if it occurs, if they're trained properly?

JIM BURNETT: I have my doubts about that, and I also think there's some danger to trying to train pilots to react the opposite of what they would otherwise--how they would otherwise react. And I think the aviation training system is fairly strained at the time anyway. So I don't--I resolve--I view that as a stop gap measure and not a very good one, and it is really necessary to get the fixes in place.

ELIZABETH FARNSWORTH: Mr. Higgins, what about--how would you--what would you recommend to our viewers who may be flying a 737?

CHARLIE HIGGINS: Well, first, I'd like to point out that there's nothing new that's happened to a 737. In other words, this particular phenomenon has existed on the airplane since the first one flew, and we have accumulated over 75 million hours on the airplane, and we don't have any evidence that we've ever had a jam of this type occur. Some recent testing has indicated that had a jam like this occurred, that there would have been evidence left after the accident to show that. So we don't think that there's any particular need for concern. We have this repetitive check in place to check for any latent jams that may occur, and like I mentioned before, we've checked the entire fleet. We have no evidence that any jam has ever occurred in the fleet, and so from our perspective, the airplane is just as safe today as it always was, and there's no need for concern on the part of the public.

ELIZABETH FARNSWORTH: And just briefly, do you believe a pilot properly trained could overcome a malfunction if it occurred?

CHARLIE HIGGINS: Yes, I do. We've demonstrated that several times in the simulator. There are other control systems available to the crew. There's the rudder, which is what could jam here potentially, and he has ailerons that he gets to have by the control wheel that he can counter the rudder with, given his immediate task is to get the airplane under control. He can then de-power the rudder system and land the airplane. So we don't think there's any particular issue at this, and, in fact, we've had some minor upsets, as I mentioned before, due to turbulence and yaw damper failures where the flight crews have demonstrated the ability to recover from an event.

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Safer Skies

February 21, 1997

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