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NTSB blames rudder in USAir crash Calls for redesign, cites other incidents Thursday, March 25, 1999 By Jonathan D. Silver and Lawrence Walsh, Post-Gazette Staff Writers
SPRINGFIELD, Va. - The National Transportation Safety Board yesterday concluded the longest aviation accident investigation in the nation's history by blaming the crash of USAir Flight 427 on the 737's rudder and calling for a new redesign to make it safer.
Although investigators clearly blamed a jammed hydraulic valve that controls the rudder for the USAir crash, another crash in Colorado and a third incident where a crash was prevented, they said there was no evidence to explain exactly how it occurred.
Investigators believe that special flight training, ongoing installation of redesigned rudder equipment ordered two years ago, and new flying techniques learned in the aftermath of Flight 427 have provided pilots with the tools they need to avert a repeat of the crash, the circumstances of which are incredibly rare, according to investigators.
Nonetheless, the NTSB recommended another redesign of the rudder, which the safety board hopes will completely eliminate the possibility that any future rudder malfunction could end in catastrophe. The board did not specifically recommend yesterday how to revamp the rudder control system.
Investigators determined that the crash of Flight 427 on Sept. 8, 1994, in Hopewell, a similar fatal accident in Colorado three years earlier that had been unsolved until now, and a near-crash over Virginia in 1996 all resulted from an unusual set of events, not fully understood, that conspired to play havoc with the rudder, making it turn in the direction opposite from what was commanded.
Those details crystallized yesterday in the ballroom of a Hilton Hotel here, where safety board Chairman Jim Hall presided over a two-day public meeting on Flight 427. Reading aloud, Hall listed his agency's jargon-laden findings and 10 safety recommendations to the FAA.
Among the recommendations were calls to assemble a panel of experts to fully analyze how the 737's rudder can malfunction and to develop tests to detect such failures.
From beginning to end, the process took only 45 minutes, a sharp contrast to the numbing day of technical presentations given by investigators on Tuesday. The board unanimously adopted the investigators' final report, which now goes to the FAA, which has the option to implement them or not.
From their special section of the ballroom, cordoned off by a blue, velvet rope, roughly 100 family members of Flight 427's 132 victims listened quietly, bursting out only once in spontaneous applause when Hall chastised the FAA for not acting more aggressively to upgrade flight data recorders aboard 737s.
Investigators were stymied in their efforts to solve the crash because Flight 427 carried a primitive flight data recorder that monitored only 11 pieces of information about the plane's operation. That information didn't include rudder movement or whether the flight crew applied pressure to the rudder pedals in the cockpit. Other airplanes in existence at the time could monitor as many as 300 pieces of information, a veritable gold mine of information for crash investigators.
Hall continued to criticize the FAA for moving too slowly to have those more-advanced data recorders installed on 737s, the world's most popular passenger plane and the workhorse of U.S. carriers. There are more than 3,000 737s in service around the globe, about a third in the domestic fleet.
"The Federal Aviation Administration failed in its responsibility to the flying public," Hall told reporters after yesterday's meeting. "I'm kind of tired of pulling the FAA. It's their turn to lead."
More information on Flight 427, including the accident investigation docket and simulated animations, is available at the NTSB Web site.
Shortly after the meeting ended, Hall and Thomas Haueter, the accident's lead investigator, received hugs, handshakes and thanks from some of the family members.
"This isn't the end; it's just the beginning," said Kristi Gerhart of Roanoke, Va., whose husband, David Lamanca, died in the crash. Gerhart is president of the Flight 427 Air Disaster Support League, formed by the victim's families. "The big question now is whether the FAA will implement the [safety] board's recommendations."
Attorney Howard Specter of Pittsburgh, who is chairman of a panel of 10 lawyers handling the liability phase of lawsuits filed against Boeing, US Airways and other defendants stemming from the Flight 427 crash, shared Gerhart's concerns about the FAA's willingness to adopt the safety board's recommendations.
"The problem that I see and fear and fully expect is that the FAA will ignore the safety-related recommendations and view them strictly as a cost-of-human life matter," Specter said. "I suspect the FAA will kowtow to the airlines and the manufacturers without regard to the NTSB's recommendations."
Now the onus is on the FAA, but top officials have indicated they are not likely to endorse a wholesale redesign of the rudder control mechanism.
Thomas McSweeny, the FAA's associate administrator of regulation and certification, said his agency has addressed the problems of the 737's rudder system.
"With the probable cause they published, we have fixed it," McSweeny said yesterday . "I have not seen any data from the board or anybody else that shows other possible failure modes [of the rudder]."
Although investigators invested countless hours over the last 4 1/2 years in their quest for the culprit in all three incidents, a definitive explanation for what caused the valve jams remains elusive.
Rather than pointing to physical evidence conclusively proving that a jam happened in flight, investigators ultimately had to rely on tests on the ground showing that a jam could occur, as well as deductive reasoning that allowed them to rule out a panoply of other possible crash causes. There has never been any proof that a valve has jammed while a plane was in the air.
"It's a circumstantial case because we cannot demonstrate right now what would cause the jam we're talking about," said Bernard Loeb, director of safety board's office of aviation safety.
Among the other possibilities hypothesized was a scenario championed by Boeing that the flight crew was startled and confused by turbulence, inadvertently made a mistake and held the rudder in the wrong position, even as the ground rushed up at them.
Computer-animated sequences shown Monday displayed in chilling detail what the view from the cockpit would have been as the plane wobbled and spun out of control, plummeting 6,000 feet in 23 seconds.
The safety board reiterated yesterday that there was no way to recover the plane at that point because it was flying at 190 knots. At that velocity, a 737's wheel cannot overpower the rudder. No one knew it at the time, though, and the training procedures now in place at a number of carriers - including US Airways - had not been developed yet.
Yesterday's findings unequivocally exonerated Capt. Peter Germano and First Officer Charles Emmett. They had piloted Flight 427 from Chicago and were descending into Pittsburgh International Airport on a calm, clear evening when the plane was jostled by turbulence called a wake vortex, caused by tightly wound coils of air streaming off the wings of an airplane four miles ahead.
That turbulence, a routine occurrence, tilted the plane to the left and the flight crew fought to right the jet by turning the wheel right. At some point, they tried to apply right rudder, but the rudder moved left instead, unbeknownst to them.
Investigators said an exhaustive analysis of the flight crew's medical health, training, and comments picked up by the plane's cockpit voice recorder during the disaster made it clear that the flight crew did everything right. It was the plane that betrayed them.
Boeing executives did not dispute the safety board's probable cause finding and said they were eager to examine the final report. The Seattle-based company has said repeatedly that it has taken steps to make a rudder reversal impossible. While not running to embrace the safety board's recommendation for a rudder redesign, Boeing did not dismiss the suggestion either.
"We have completely eliminated any possibility of reversal. There is no mode that we're aware of today that could cause the rudder to reverse," said Charles Higgins, vice president of airplane safety and airworthiness. "We're going to do everything we can to look at the 737 rudder system to see if there's any more improvements that can be made...If it can be determined there is a safety benefit and it can be done safely throughout the world, then we'll step up to it," Higgins said.
Boeing Co. is unlikely to suffer permanent damage to its finances or reputation as a result of the NTSB's ruling yesterday, industry analysts said yesterday.
"The potential impact on Boeing, short of grounding the aircraft or requiring a whole new tail section be put on every aircraft, would be minimal," said Paul Nesbit, an analyst at JSA Research.
Boeing's stock even managed a small gain, despite the ruling by the NTSB. In trading on the New York Stock Exchange, Boeing closed up 183/4 cents at $34.311/4 a share.
The Associated Press contributed to this report.
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