New Information Casts Doubt
On EgyptAir Suicide Theory
by Sean Broderick
06/13/00 10:24:38 AM U.S. EDT
Information in the soon-to-be-made-public docket on the EgyptAir Flight 990
investigation casts serious doubt on the much-publicized theory that a first
officer purposely flew the jet into the ocean, sources with knowledge of the
probe tell
AviationNow.com
and
Aviation Week & Space Technology
.
The theory was given life after preliminary analysis of the cockpit voice recorder (CVR) revealed an EgyptAir pilot left alone in the cockpit -- most likely first officer Gameel el-Batouty -- manually disconnected the autopilot just before the aircraft began a steep dive. Analysis of the flight data recorder (FDR) showed that about 20 seconds into the dive, the Boeing 767-300ERs elevators were being moved in opposite directions, or split. Investigators considered this a clue that Batouty and captain Ahmed al-Habashy, who re-entered the cockpit as the dive began, were battling for control of the airplane.
But follow-up analysis of both the CVR and FDR revealed details that dont fit well with the suicide theory. Investigators found that the split-elevator readings came when the 767 was traveling well beyond the aircrafts designed maximum operating speed possibly close enough to the speed of sound to create a physical anomaly that could cause the elevators to split without any input from the cockpit, sources said.
Further, said experts with FDR analysis experience, the recorders arent designed to collect data at such speeds, meaning any readings during that part of Flight 990s descent could be unreliable. Data recorded at the instant the elevators reportedly split also indicates significant abnormalities with either the FDR data or the forces acting on the jet, sources said. The FDR indicated abnormal flight control surface deflections at that instant, including movements of the 767s outboard ailerons. Those control surfaces are used only during takeoff and landing, and should not have been movable at the speed that Flight 990 was traveling, sources said.
The 767 had an advanced FDR, but the recorder cant tell investigators
what forces were being applied to the control column, control wheel, or rudder
pedals. Movements of flight control surfaces such as the elevators offer the
only clues to what the pilots were doing. After five days of FDR analysis and
one day of CVR analysis turned up no obvious factors that would have triggered
a dive, investigators began to consider a deliberate act
suicide. Sources with knowledge of the probe believe results from the follow-up
recorder analysis, combined with other findings, show that several other
possibilities including a mechanical failure havent been exhaustively explored by investigators and must be considered.
-- Aviation Expert (maybe@Hawk.is right too), June 14, 2000