Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 30
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160 24
According to the speech study, the relief first officer’s rate of speech did not increase
significantly when saying, “I rely on God,” during the pitchdown and descent.
The Safety Board also examined the length of time between the relief first officer’s
“I rely on God” statements for evidence of psychological stress. About 67 seconds passed
between the first and second utterances of the phrase, 8.1 seconds passed between the
second and third, and 0.51 to 0.70 seconds passed between subsequent utterances of the
phrase. According to the speech study, after the second utterance, the data suggested a
“rhythmic repetition of the phrase rather than an accelerating trend, as might be expected
with increased psychological stress.”
The speech study concluded that, although the relief first officer’s speech
displayed some evidence of increased psychological stress between the first and second
utterance of “I rely on God” (when the airplane was still in level flight at cruise altitude),
there was no evidence of increased psychological stress in the relief first officer’s speech
after he uttered the phrase the second time. As previously discussed, after the second
utterance of the phrase, the airplane departed level flight to a steep nose-down pitch
attitude and experienced an increased nose-down pitch attitude and rate of descent and a
decrease in its load factor (to negative Gs) while the relief first officer repeated, “I rely on
God,” the last nine times.
Unintelligible Comment
The Safety Board’s audio examination and sound spectrum analysis of the
unintelligible comment that was recorded by the CAM at 0148:30 showed that it appeared
to have characteristics consistent with human speech. It consisted of three syllables, with
the accent on the second syllable, and was probably spoken very softly (as shown by very
poor speech signal definition). The speech examination study indicated that the comment
was preceded by 19.2 seconds without speech and followed by 9.2 seconds without
speech, suggesting that it was an isolated statement rather than part of a conversation.
Unfortunately, the speech segment was not long or clear enough to determine what was
said and who said it. However, two speech characteristics of the unintelligible comment—
fundamental frequency and formant dispersion—displayed values that, of the six pilots’
speech that had been recorded earlier on the CVR tape, most closely resembled the speech
values displayed by the relief first officer.
As previously discussed, and as noted as follows in the CVR transcript:
The five Arabic speaking members of the [CVR] group concur that they do not
recognize this as an Arabic word, words, or phrase. The entire group agrees that
three syllables are heard and the accent is on the second syllable. Four Arabic
speaking group members believe that they heard words similar to ‘control it.’ One
English speaking member believes that he heard a word similar to ‘hydraulic.’
The five other members believe that the word(s) were unintelligible.
NTSB/AAB-02/01
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