Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 72
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160 66
Summary
1. The accident airplane’s nose-down movements did not result from a failure in
the elevator control system or any other airplane failure.
There was no evidence of any failure condition within the elevator system of
the accident airplane that would have caused or contributed to the initial
pitchover or prevented a successful recovery.
No mechanical failure scenario resulted in airplane movements that matched
the flight data recorder data from the accident airplane.
Even assuming that one of the four examined failure scenarios that the
investigation evaluated in depth had occurred, the accident airplane would
still have been recoverable because of the capabilities of the Boeing 767’s
redundant elevator system.
2. The accident airplane’s movements during the initial part of the accident
sequence were the result of the relief first officer’s manipulation of the
controls.
At the relief first officer’s suggestion, a transfer of control at the first officer’s
position occurred earlier than normal during the accident flight.
The relief first officer was alone in the cockpit when he manually
disconnected the autopilot and moved the throttle levers from cruise to idle;
there was no evidence of any airplane system malfunction, conflicting air
traffic, or other event that would have prompted these actions.
The nature and degree of the subsequent nose-down elevator movements were
not consistent with those that might have resulted from a mechanical failure
but could be explained by pilot input.
There was no apparent reason for the relief first officer’s nose-down elevator
inputs.
The relief first officer’s calm repetition of the phrase “I rely on God,”
beginning about 74 seconds before the airplane’s dive began and continuing
until just after the captain returned to the cockpit (about 14 seconds into the
dive), without any call for help or other audible reaction of surprise or alarm
from the relief first officer after the sudden dive is not consistent with the
reaction that would be expected from a pilot who is encountering an
unexpected or uncommanded flight condition.
The absence of any attempt by the relief first officer to recover from the
accident airplane’s sudden dive is also inconsistent with his having
encountered an unexpected or uncommanded flight condition.
The relief first officer’s failure to respond to the command captain’s questions
(“What’s happening? What’s happening?”) upon the captain’s return to the
cockpit is also inconsistent with the reaction that would be expected from a
pilot who is encountering an uncommanded or undesired flight condition.
NTSB/AAB-02/01
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