Last Words of Aeromexico Jet Pilot: ‘This Can’t Be!’

“Oh . . . this can’t be!”

These were the words of Arturo Valdez Prom, the captain of Aeromexico Flight 498, as he realized that something terrible was happening to the DC-9 during its approach to Los Angeles International Airport Aug. 31.

A transcript of the cockpit voice recorder, which contains only snippets of the Spanish conversation of the Aeromexico crew, was released here Thursday by the National Transportation Safety Board.

Whether Prom or his co-pilot, Hector Valencia, actually knew that they had collided with a small Piper airplane over Cerritos may never be known.

Although the tape revealed Prom’s astonishment, it was of such “consistently poor quality” that investigators could glean little new information about the collision, which killed 82 people, including 15 on the ground.

James R. Cash, an air safety investigator in charge of preparing the transcript, reported that the final segments of the 30-minute tape are of “very poor quality.” This, he said, was not because of the accident, but because the model of the plane’s cockpit voice recorder “has a history of tape tension and recording quality problems.”

The sound was so distorted and noisy that it was difficult for those transcribing the tape to understand the crew’s conversation, Cash said.

“The flight crew used the cockpit overhead radio speakers for reception of air traffic control transmissions,” Cash said. “This impaired intelligibility because of the close proximity of those speakers to the cockpit area microphone, the loud radio volume and the large number of transmissions in the Los Angeles area.”

What little that investigators could hear indicated that Flight 498 was proceeding routinely at 11:47 a.m. PDT when the crew radioed a “good morning” to the Los Angeles Terminal Radar Approach Control facility, which told them to prepare for a final approach to Runway 25 Left at LAX.

Other than the sound of the attendant bell and a few routine instructions from the crew, nothing else from inside the cockpit is audible on the transcript until 11:51, when the captain says: “Thank you.” The context of that statement is unclear.

A few seconds later, the air-to-ground communications picked up on the cockpit recording indicate that the controller advised the Aeromexico jet of a runway change, apparently because a Wings West flight had also been cleared for Runway 25 Left.

Controller: “Aeromexico 498, maintain your present speed.”

Cockpit: “Roger. Aeromexico 498. Uh, what speed do you want. We’re reducing to two niner . . . to one niner zero.”

Controller: “OK, you can hold what you have, sir, and we have a change in plans here, stand by.”

Cockpit: “All right, we’ll maintain one . . . nine zero.”

Seconds later, at 11:52 a.m., there is the first indication from the crew that something has happened.

“Oh (expletive deleted), this can’t be!” Prom exclaimed.

There are no further words recorded in the cockpit, although the recorder did pick up the voice of the controller advising the Aeromexico jet to use Runway 24 Right. The recording ended 22 seconds after Prom’s exclamation, presumably when the plane hit the ground.

The transcript was reviewed by National Transportation Safety Board investigators, Federal Aviation Administration officials, a representative from the plane’s manufacturer, McDonnell Douglas, and aviation authorities from Mexico.

The safety board released a separate report of its examination of the flight data recorder, which was also recovered from the wreckage and which keeps a permanent flight record of the airplane’s altitude, airspeed and heading.

The data collected by the recorder showed that the flight was proceeding smoothly as the Aeromexico jet started its descent from 10,133 feet with an airspeed of 347 knots.

About 7 1/2 minutes later, as instructed by the controller, the aircraft had descended to about 7,000 feet, with an airspeed of 228 knots. Corrected data from the recorder indicated the collision occurred at 6,589 feet.

‘All Bets Were Off’

There was additional data for the 22 seconds between the collision and the impact on the ground, but Ira Furman, a spokesman for the NTSB, said these final readings--which indicate that the doomed airliner gyrated wildly--are probably unreliable.

“Once the plane was hit, all bets were off on the numbers,” Furman said.

Furman said altitude readings from the data recorder were corrected by more than 500 feet after it was noted that the recording indicated that the plane was eight feet below sea level when it landed at Tijuana, the last stop before the crash. The Tijuana airport is actually about 500 feet above sea level.

The erroneous readings show only what the recorder was inscribing and do not indicate that any of the pilot’s instruments were malfunctioning, Furman said. He said there may be later corrections in the airspeed readings.

Despite the information provided by the voice and flight data recorders, several key questions are still unanswered about the collision that resulted in a firestorm on the ground that destroyed or damaged 17 homes.

Whether either pilot saw the other plane may remain a mystery forever. Neither pilot was warned by a controller. The controller handling Flight 498 reportedly has said he never saw the Piper on his radar screen, although officials have said that computer data indicate that the radar system did pick up the smaller plane. None of the recordings give evidence that the Aeromexico plane tried any evasive maneuvers. There were no recorders aboard the light plane.

In the days after the disaster, some federal officials said that the controller directing Flight 498 may have been distracted by a third aircraft, a private plane flown by Roland P. Furman that allegedly was in the Los Angeles Terminal Control Area without permission.

A Federal Aviation Administration transcript of the controller’s radio exchanges with pilots Aug. 31 shows that the controller had two brief exchanges with Furman before the collision, and shows that the controller was talking to Furman when the Aeromexico pilot suddenly realized his jetliner was in trouble.

But sources close to the investigation, noting Thursday that the controller contacted Flight 498 before and after his exchanges with Furman, discounted speculation that Furman’s plane had distracted the controller’s attention from the Aeromexico jet. The FAA has announced that it intends to suspend Furman’s pilot’s license for 180 days. Furman, 55, of Buena Park, has declined to comment on the allegation that he violated the Terminal Control Area.

Heart Attack Question

Why the Piper strayed without authorization into the restricted Terminal Control Area approach route normally reserved for aircraft preparing to land at Los Angeles International Airport may remain pure speculation. The reason, once again, is the lack of recordings or survivors.

Whether the pilot of the Piper, William K. Kramer, 53, suffered a heart attack in the seconds before the collision also may never be resolved. The Los Angeles County coroner’s office says he suffered such an attack “within minutes before his death,” but pathologists say it is often difficult, if not impossible, to determine whether a person had suffered a heart attack within the last day of his life--much less within minutes of death.

NTSB investigators are still reviewing testimony from dozens of witnesses and poring over technical reports from engineers who studied the wreckage. Hearings will be held in Southern California in December at which NTSB officials will hear testimony from interested parties. A final determination as to the cause of the crash is not expected until next year.

Penny Pagano reported from Washington and Eric Malnic from Los Angeles.