The Airbus memo referenced in a New York Times article today appears to be different than the report cited in a recent thread regarding structural design loads on the A300 fin. Some of this may be 'blame game' maneurvering before the NTSB hearing later this month on AA587, but it does seem a bit untoward that Airbus, based on its analysis of an earlier incident, kept internal a memo warning that swinging the A300 rudder may result in the fin failing.
97 Memo Cited in '01 Queens Airliner Crash
By MATTHEW L. WALD
WASHINGTON, Oct. 11 - An airplane manufacturer's memo written in June 1997 explicitly describes the hazards of the maneuver that caused the November 2001 crash of an American Airlines plane in Belle Harbor, Queens, but the memo was kept within the company, and the pilot was never warned about the procedure.
American Airlines obtained the memo a few months ago from the manufacturer, Airbus, as part of its suit over how the companies will share the payments to the families of the 265 people killed in the crash of Flight 587. The memo is now being cited by American and the pilots' union in an effort to put part of the blame on Airbus.
The maneuver involved swinging the rudder from side to side, and the memo, written after a 1997 episode with a different American Airlines flight in the same kind of plane, an A300, warns that it could cause the tail to break off. That is what happened to Flight 587.
After the crash, the National Transportation Safety Board issued a recommendation against the maneuver. If Airbus had shown the memo to the board before the crash, "instead of concealing it from them, the N.T.S.B. would have issued the recommendation before the crash," said John A. David, an American Airlines pilot who is the chief representative of the union, the Air Line Pilots Association, in the investigation.
Clay McConnell, a spokesman for Airbus, said that at the time the memo was written, Airbus was not a party to the investigation of the first event, and that when it did join, it was involved with crew performance, not structural issues.
The memo, from a German member of the Airbus consortium, Daimler-Benz Aerospace, said that "rudder movements from left limit to right limit will produce loads on the fin/rear fuselage above ultimate design load" - the amount of force that a part is designed to handle without breaking.
The memo's main point was that the tail of the plane in the 1997 event should be inspected. It was, and no damage was found, but it was reinspected more thoroughly after the 2001 crash, when some problems were found.
In the Flight 587 crash, the co-pilot, flying the plane, moved the rudder back and forth when it encountered the wake of a plane that had taken off 140 seconds earlier from Kennedy International Airport. Pilots are warned not to use the rudder above a certain speed, which varies by airplane, but Flight 587 was still below that speed. They were not warned, until after the crash, never to use the rudder in alternating directions.
The safety board warning went to all jet airliner pilots, and experts say that the A300 is no more vulnerable to this maneuver than many other planes. Separately, however, the airline is arguing that a system called the "rudder limiter," which keeps a pilot from moving the rudder farther than is safe at the airplane's speed, does not work well on the A300.
The safety board has scheduled a meeting for Oct. 26 to establish the probable cause of the crash. Under its charter from Congress, the board finds probable cause, not fault, but its findings could influence the outcome of the litigation between the airline and the plane manufacturer.
The union and the airline are contending that in an era of very few passenger airline crashes, reducing the accident rate further will require that all elements of the industry volunteer any information they have on any potential safety problem.
In the 1997 episode, the crew of an American airlines plane near West Palm Beach, Fla., mismanaged the controls and allowed airspeed to fall too low. When the plane slowed down to the point that it could not stay in the air, the crew performed a sloppy recovery but averted a crash. But the investigation focused on the initial error and the poor recovery, and not the rudder issue.
Mr. McConnell of Airbus said his company had stressed to American after the 1997 event that pilots should not use the rudder in recovering stability.
"If the pilots didn't know it, it isn't for our lack of trying," he said. He acknowledged that the advice concerned not using the rudder, and not the more specific case of using the rudder in alternating directions. But, he said, "there is no good piloting reason to use alternating rudder, none, in the history of aviation."