Changes urged in how FAA approves airplanes
Thursday, April 27, 2006
By MATTHEW L. WALD
THE NEW YORK TIMES
WASHINGTON – The National Transportation Safety Board is recommending that the Federal Aviation Administration change how it approves new airplane designs, saying that problems with the process contributed to four crashes from 1994 to 2001 that killed more than 700 people.
The safety board, an advisory body, stressed that overall, airline flying was extremely safe, but that the four accidents had killed 60 percent of those who died in jet crashes over the period.
Past shortcomings in design review are important because a new generation of jets, which will be flying for the next 30 to 50 years, is being tested or designed, and includes new challenges. The newest planes require software that must be analyzed and maintained. They also have composite materials developed relatively recently; a new question is how well the composites will age. In addition, the design of computerized cockpits must be studied to make sure it does not encourage human error.
The report that the safety board issued Tuesday did not provide new details about the four crashes but did link them as part of a trend.
The board said that an Alaska Airlines plane crashed off the California coast in January 2000, killing all 88 people on board, because of a failure of a part that controlled the horizontal parts of the tail. The problem was traced to the airline’s change in the maintenance procedure for the part, whose design was approved by the FAA in 1965. The change was made without sufficient analysis of the design, and the FAA did not preserve enough details about the assumptions behind its 1965 decision, board staff members said.
In the case of Trans World Airlines Flight 800, a Boeing 747 that exploded off Long Island in 1996, killing 230 people, the design problem involved the fuel tank. In the case of USAir Flight 427, a Boeing 737 that crashed near Pittsburgh in September 1994, killing 132 people, the board pointed to assumptions about a backup system for a hydraulic valve that controlled movement of the rudder.
American Airlines Flight 587, an Airbus A300 that had just left Kennedy Airport in New York, crashed in November 2001, in part because the pedals used to control the rudder of the plane were difficult to use properly at the speed the plane was flying. That crash killed 265.
Experts have worried for years about the process that the FAA uses to approve new designs. One board member, Debbie Hersman, referred to a report by the National Academy of Sciences that said that airplanes were becoming more complex and that the FAA was not keeping up, relying to a worrisome degree on the airplane manufacturers. That report was published in 1980. “This is like groundhog day,” Hersman said of the renewed concern.
The FAA itself, chastened by the four crashes, commissioned a study of its “design certification” process jointly with outside experts. They made their recommendations in March 2002.
The safety board sent three recommendations to the FAA Tuesday. One was to list systems on each plane that are critical to safety, and preserve the “rationale, analysis methods, failure scenarios, supporting evidence, and associated issue papers.” Another was to include “human/airplane system interaction failures,” in which the set-up of the controls can encourage error. The third was to use operating experience during the decades that a typical model is in use to check whether the assumptions underlying the certification decision were correct.
John Hickey, the head of the FAA’s Aircraft Certification Service, agreed with some of the safety board’s findings. The FAA gathers extensive data on the performance of planes and components but does not now use it to see if the initial approval, or certification, was correct, he said.
“What we tend not to do in a systematic way is take a lot of the safety information and go back and revalidate the certification or change it if we made a faulty assumption,” Hickey said.
The safety board chairman, Mark Rosenker, said, “every time we sit down to do an analysis, every time we study an accident, we come up with something we didn’t know that we didn’t know.”
For example, he said, before the Trans World Airlines Flight 800 crash, the FAA did not know, or simply did not believe, that a spark could find its way into the fuel tank.