Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 70
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160 64
just after the elevator split began, the engine start lever switches were moved to the cutoff
position, the throttle levers were advanced to full throttle, and the speedbrakes were
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deployed.
After the throttle levers were advanced (but the engines did not respond), the
captain reacted with surprise, asking the relief first officer, “What is this? What is this?
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Did you shut the engine(s)?”
The timing and direction of the left elevator motions
during this time suggest that the captain, who had likely been using both hands to pull aft
on the left control column, released his right hand to advance the throttles and deploy the
speedbrakes, resulting in a decrease in his total aft pressure on the control column, which
was reflected in the decrease in the left elevator’s nose-up deflection that was recorded by
the FDR at this time. Subsequently, when the captain likely had returned his right hand to
the control column, the FDR recorded a corresponding increase in the left elevator’s
nose-up deflection. As previously stated, tests and simulations demonstrated that a pilot
seated in the captain’s position could easily have advanced the throttles, moved his hand a
little to the left, and deployed the speedbrakes in the 3 to 4 seconds it took for these events
to occur.
Concurrent with the brief downward motion of the left elevator that was recorded
when the throttles were advanced and the speedbrakes deployed, a brief downward motion
of the right elevator was recorded. This movement of the right elevator suggests that when
the captain’s aft pressure on the left control column decreased, the relief first officer’s
sustained forward pressure on the right control column caused that column to move
forward briefly. Although it would have been physically possible for the relief first officer
to have advanced the throttles and deployed the speedbrakes, the evidence does not
support the notion that the relief first officer performed these actions. Rather, the evidence
indicates that the relief first officer moved the engine start lever switches to the cutoff
position (a counterproductive action, in terms of recovery), whereas the captain deployed
the speedbrakes in an attempt to arrest the airplane’s descent.
Additionally, the surprised reaction from the captain when the engines did not
respond to the throttle movement (“What is this? What is this? Did you shut the
engine(s)?”) suggested that it was he (not the relief first officer) who advanced the throttle
levers. This response clearly indicated that the captain was unaware that the engine start
lever switches had been moved to the cutoff position, that such an action was at odds with
his intentions, and that it was, therefore, not part of a mutual, cooperative troubleshooting
exercise between the captain and relief first officer.
At 0150:26.55, the captain stated, “Get away in the engines,” and at 0150:28.85,
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he stated, “shut the engines.”
At 0150:29.66, the relief first officer responded for the
first (and only) time after the captain returned to the cockpit, stating, “It’s shut.”
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Tests and simulations demonstrated that the magnitude of the elevator split would vary, but a split
could be maintained even when the pilot in the left seat temporarily removed his right hand from the control
yoke to advance the throttles and deploy the speedbrakes and the pilot in the right seat temporarily removed
his left hand from the control yoke to move the engine start lever switches to the cutoff position.
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The Safety Board notes that the captain’s statement “What is this? What is this? Did you shut the
engine(s)?” might reflect the beginning of a suspicion that the relief first officer’s actions were not
appropriate for recovery.
NTSB/AAB-02/01
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