AA Maintains Crash Caused By Design Flaw
From the start, NTSB
investigators probing the crash of American Airlines Flight 587 in
November, 2001, have concentrated on co-pilot Sten Molin's
manipulation of the rudder pedals. Just after taking off from JFK
Airport in New York, the aircraft encountered extreme turbulence.
Attempting to counteract the turbulence, co-pilot Molin actuated
the rudder of the Airbus A300-600 at a speed of 250 kts. To this
point, theories have suggested that Molin over manipulated the
rudder, causing the aircraft's vertical stabilizer to snap
completely away from the airframe. The aircraft spun into a
residential area of Queens, killing 265 people.
But now, an outside expert hired by the NTSB, suggests the very
design of the aircraft could have played a major part in the crash.
That plays right into American's argument that the rudder design on
the A300-600 is flawed and that Airbus is to blame. It's the
centerpiece of an ongoing argument between American and the
European aircraft company and, in itself, is already
The vice chairman of the mechanical and aeronautical engineering
department at the University of California/Davis, Ronald Hess, has
reportedly found the rudder controls of the A300-600 are much more
sensitive than the rudder controls on other, comparable aircraft.
His findings, accepted into evidence by the NTSB, finds that the
A300-600 rudder controls are extremely sensitive to air crew
USA Today reports Hess
concludes the November 12, 2001 accident is "consistent" with a
rare phenomenon that is somewhat akin to over steering a skidding
car. Instead of stabilizing the aircraft, Molin's rudder
application made things worse, eventually leading to the
delamination of the entire 27-foot tall vertical stabilizer.
American has come under fire during the NTSB investigation for
the way it teaches pilots to use the rudder in extreme situations.
The agency also criticized the rudder controls in American's A300
simulators as not truly representing the behavior of those controls
in actual flight. But American says its training is no different
than that of other airlines.
But in his report to the NTSB, USA Today says Hess cited extreme
sensitivity in the rudder controls of an A300-600 -- especially at
NTSB documents show that, during his preflight, Molin applied 65
pounds of pressure to each rudder pedal. The pedals moved a total
of four inches and performed as advertised. But just 85 seconds
after takeoff, at 250 kts, the pedal moved just 1.3 inches and
required far less pressure from Molin's foot, once it was in
That's an important distinction. Rudder pedals are designed so
that it takes deliberate pressure -- at least 20 pounds, in the
case of the A300-600 -- to move them. That way, you can't
accidentally kick a rudder pedal and throw the aircraft into an
uncontrollable skid. But once the Airbus rudder is in motion, Hess
found that it took far less pressure to move it to the stops. He
reported to the NTSB that it only took another 10 pounds of
pressure, whereas the rudder controls on a Boeing 767 under similar
conditions, requires 63 additional pounds of pressure before fully
articulating one way or the other.
Airbus spokesman Clay McConnell says the amount of pressure
required to move the rudder from stop to stop wasn't a factor in
the AA 587 accident because Molin applied far more pressure on the
pedals than would have been required in any comparable aircraft.
The company says the A300-600 and the A310, which share the same
rudder design, have flown 16 million hours since being introduced
in the early 1980s, and "there has never been an issue with rudder