WASHINGTON — The tape-recording of the cockpit conversation in the Aeromexico jet that collided with a private plane over Cerritos provides no evidence that the airline pilot ever saw the smaller aircraft, a National Transportation Safety Board official said Tuesday.
John Lauber, who is heading the federal agency's investigation of the accident, said that because of the "very poor condition" of the tape, there are huge gaps in the recording and only "occasional scraps" of the Spanish conversation of the DC-9 crew.
"Because of the gaps, we can't divine what is there," Lauber said in an interview. He said the poor physical condition of the tape was caused by mechanical difficulties with the recording device before the accident.
"It was folded and creased in such a way that it recorded only intermittently," he said of the cockpit tape. "It was very difficult to get anything from it."
Question of Evasive Action
Lauber said the board could not determine whether either pilot saw the other or whether the Aeromexico pilot tried to take evasive action. But he noted that none of the 13 witnesses interviewed by safety board investigators reported that the jetliner took such action.
Although the cockpit voice recorder will provide little information about what happened in the final minutes before the crash, the board still has important data from the other "black box" retrieved from the wreckage, the flight data recorder, which collects a variety of information as the airplane flies, including heading, air speed and altitude.
The flight data recordings are in better condition than the cockpit voice recorder tape. The National Transportation Safety Board will use the data from both devices, along with other reports from staff investigators, to try to determine the cause of the in-flight collision.
"Fortunately, in this case, we have a lot of other sources of information, including the flight data recorder, the recorded radar data and the air traffic control communications," Lauber said. "We will be able to piece together the critical elements."
Similar information from the private plane is not available to investigators because such small planes are not required to carry the types of recording devices required in larger craft.
While the Piper Cherokee had a transponder--a device that emits a signal alerting air traffic controllers of its presence--it did not have equipment that would also relay its exact altitude.
The Aeromexico DC-9 was bound for Los Angeles from Mexico City on Aug. 31 when it collided with the small plane and then plunged into a residential neighborhood in Cerritos, about 20 miles southeast of Los Angeles International Airport. The accident killed 82 people, including 15 on the ground.
Safety board spokesman Ira Furman said that transcripts of the cockpit voice recorder and the flight data recorder, as well as other technical reports, will be released Oct. 30.
The safety board has also scheduled a public hearing on the accident for Dec. 2 in Los Angeles. Details of hearings, including the witnesses, will be announced later.