Aviation Week says new data on EgyptAir crash casts doubt on the NTSB's suicide theory

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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

Answers

I'm sure this has been asked and answered on one of the previous threads -- but then, someone has to ask the stupid questions: Why would the elevators on a commercial airliner (or any plane, for that matter) be designed so they could be "split" in the first place?

-- I'm Here, I'm There (I'm Everywhere@so.beware), June 15, 2000.

I'm not an aero engineer, just The Engineer. But from what I've read they aren't designed to work that way. It's a failure that happens. It supposedly happened to a Mexican Airline plane while it was still on the ground.

-- The Engineer (spcengineer@yahoo.com), June 15, 2000.

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