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Oakland ARTCC to Oakland Approach Control. At this time, the aircraft's radar target indicated the aircraft was three miles southeast of the Altamont In- tersection.

At 0611753, the flight established radio contact with Oakland Approach Control who transmitted appropriate control instructions and the current altimeter setting, and advised that the aircraft‘s transmission was garbled. At 06h8:09, Flight 773 responded: "Roger, how do you read now?"

The approach controller replied: "It's still has the same . . ., sounds like overmodulation."

Immediately following this transmission, at 06h8:15, a high-pitched message was heard and recorded on the Oakland Approach Control tape. The con- tent of this message was not clear; however, on the basis of laboratory analysis, the most probable message was determined to be: "Skipbers shot. We're ben shot. (I was) Try 'in ta help."_3_/ The approach controller requested that the speaker "say again". No other transmissions were heard from Flight 7733.

Shortly thereafter, the radar target of Flight 773 was observed to become weak and then to disappear from the scope at a point approximately 18-1/2 nau- tical miles from the Oakland radar antenna site.y The approach controller at- tempted to contact the flight but without success.

A message was then broadcast to Flight 773 advising that radar contact had been lost, and an alternate navigational routing to San Francisco was provided.

Another aircraft in the immediate vicinity, United Flight 593, was queried to determine whether that crew had Flight 7'73 in sight. Their report was nega- tive. At 0651:20, United Flight 593 reported: "There's a black cloud of smoke coming up through the undercast at ... three-thirty-four o'clock position right now. Looks like oil or gasoline fire."

at 06h9:25,5 a seismograph station located at Camp Parks, California, ap- proximately 2-1 nautical miles south of the accident site recorded a dis- turbance of undetermined origin.

g/ The Board sent the original tape to the Bell Telephone Laboratories for further analysis. On the basis of spectrogram comparisons provided by earlier recordings known to be the captain and first officer, it was determined that the final message matched best the voice of the first officer. "I was“ is shown in parenthesis to emphasize the uncertainty of these two words. The two utterances of "shot" and the one of "help" are probably the most reliable of the several words of the message.

5/ This mileage is based on the ASR antenna site located on the southerly side of runway 29 at Oakland Airport.

5/ The seismograph is located at 37°13'50" north latitude 12105h'10n west

ﬁﬁude. Accuracy of the recorded time is within five seconds in any ELI-hour