Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 65

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Events Before and During the Initial Descent, While the Relief
First Officer Was Alone in the Cockpit
About 20 minutes after takeoff (about 0140), the relief first officer suggested that
he relieve the command first officer. A transfer of control this early in the flight was
contrary to the EgyptAir practice typically agreed-upon by flight crews of waiting until
3 or 4 hours into the flight before relieving the command crewmembers. The command
first officer initially reacted with surprise and resistance to the relief first officer’s
suggestion that he assume first officer duties at that time, indicating that the relief first
officer’s suggestion was unexpected. However, after some discussion, the command first
officer agreed to the change, and sounds recorded by the CVR indicated that, about 0142,
the command first officer vacated and the relief first officer moved into the first officer’s
seat.
About 0147, the relief first officer asked an unidentified crewmember to return a
pen to another first officer, who was in the cabin. The unidentified crewmember agreed
and left the cockpit. At 0148:03, the command captain excused himself from the cockpit,
saying that he wanted to “take a quick trip to the toilet…before it gets crowded.” While
the command captain was excusing himself, the CVR recorded the sound of an electric
seat motor, presumably the captain’s, as he maneuvered to leave his seat and the
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cockpit.
At 0148:18.55, the CVR recorded a sound similar to the cockpit door
operating.
The Safety Board considered whether another flight crewmember might have been
in the cockpit with the relief first officer during this time period. However, careful
laboratory examination of the CVR recording indicated that the CVR did not record any
speech or human sounds other than those attributed to the captain and relief first officer
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from 0148:30 until the end of the recording at 0150:38.47.
The Board determined that
the possibility that another person, especially a pilot, was present during the airplane’s
sudden transition from cruise flight to steep descent and did not audibly express surprise at
the abrupt change in the flight situation (as the captain did when he returned to the
cockpit) or offer help/suggestions on how to deal with the emergency situation was
extremely unlikely. Therefore, the evidence indicates that the relief first officer was alone
in the cockpit from about 0148:19, when the command captain left the cockpit, to
0150:06, when he returned to the cockpit.
Ten seconds after the unintelligible comment was made (at 0148:40), the relief
first officer stated quietly, “I rely on God.” At 0149:18, the CVR recorded a “whirring
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This electric seat motor was recorded by the cockpit area microphone (CAM) but not by the hot
microphone at the first officer’s position, which (as previously discussed) was likely stowed at the first
officer’s side of the airplane. Because of its position on the right side of the airplane and its directionally
sensitive nature, it is likely that all seat motions recorded by the hot microphone at the first officer’s position
after 0141 represented motions of the right seat.
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As previously discussed, about 0148:30, the CVR recorded an unintelligible comment that could not
positively be attributed to any previously identified crewmember. Two speech characteristics of the
unintelligible comment (fundamental frequency and formant dispersion) more closely resembled values
displayed by the relief first officer than by the other voices evaluated.
NTSB/AAB-02/01

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