Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 159
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160 42.
(Page 75) The NTSB concludes that the Captain made the nose-up elevator
movements when he returned to the cockpit. Once again, this statement reflects more the
NTSB’s conjecture than any supportable facts. Because there is no FDR record of control
column movement or force, there is absolutely no basis to claim that the Captain rather than the
RFO, or that the Captain alone and not along with the RFO, provided nose-up elevator inputs.
As previously pointed out, the RFO could have tried to move the elevator nose-up, but those
efforts may not have shown up on the FDR if the force applied was insufficient to overcome a
dual PCA failure. The NTSB’s failure to provide an objective analysis of the evidence shows its
intent to support a predetermined probable cause.
43.
(Pages 75-76) The contention that the elevators would be minimally affected by
aerodynamic forces at .99 Mach is not supported by any validated test data. As noted previously,
the extrapolation of airplane performance is not appropriate for the transonic speeds experienced
by Flight 990. Consequently, the conclusion that the elevator split was caused by different
inputs to each elevator surface is not supported by reliable evidence. More importantly,
however, even if differing inputs were the cause of the split, there is no basis other than shear
speculation to conclude that the different inputs were the result of a struggle between the Captain
and the RFO. In fact, it is just as reasonable (and even more likely) that different control inputs
were in response to differing perceptions as to the airplane’s attitude and the input necessary to
affect a recovery. If the RFO believed that the pitch was increasing too much, he would push the
column forward. A split would occur if, at the same time, the Captain believed that the
increasing pitch needed to be sustained, and he pulled back. Remarkably, within just a few
seconds of the split, the Captain reversed course and reduced the nose-up deflection of the left
elevator. It seems reasonable that this action was due to the Captain perceiving, as the RFO had,
that the pitch needed to be moderated. There is no indication that the Captain’s decreasing nose-
up input was because the alleged struggle was “over.”
44.
(Page 76) The NTSB’s statement that the Captain’s actions just after the split
“were consistent with an attempt to recover the airplane, and the relief first officer’s were not” is
42
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