2 Loud Bangs Heard on Jet Just Before Crash

Two loud bangs were heard aboard Alaska Airlines Flight 261 in the minutes before it crashed, including one that came immediately before the plane seemed to go out of control and plunge into the Pacific Ocean, federal safety officials said Friday.

Investigators looking into the crash off the Ventura County coast refused to speculate about what caused the bangs, the last of which could be heard clearly on the flight data recorder recovered from the sunken wreckage.

One aviation safety expert, however, said the most likely explanation is that some part of the plane’s tail snapped--perhaps the horizontal stabilizer used to maintain the plane’s up or down angle.

“It sounds like something broke, like some sort of structural failure in back, probably relating to the stabilizer itself coming apart,” said Barry Schiff, a retired TWA captain and a respected aviation safety consultant.

The investigation into the crash of Flight 261 has moved with unusual speed, in part because the pilots discussed their problems with air traffic controllers before crashing, and in part because the two black boxes--the flight data recorder and cockpit voice recorder--were found so soon.

Now investigators must turn their attention to the painstaking job of assembling enough data and debris to figure out exactly what happened to the ill-fated jet--and why.

At this point, no decision has been made on whether to raise any of the wreckage, National Transportation Safety Board officials said. It is possible that the safety board could decide to recover only pertinent sections of the plane, such as the tail, chunks of which were seen in a videotape shot by one of the Navy’s submersibles Thursday.

John Hammerschmidt, a top NTSB official, said the agency is focusing on videotaping all the wreckage and mapping the site. Until that is done, he said, the wreckage will be left exactly as it is.

That suggests the recovery team won’t immediately attempt to bring up any bodies found amid the wreckage. Hammerschmidt said safety officials won’t comment on any matters related to the bodies, except to say that recovery of remains “is continuing right now.” The pilots of the 8-year-old MD-83 aircraft, built in Long Beach by McDonnell Douglas, had reported that they were having stabilizer problems throughout the 30 minutes documented by the cockpit voice recorder.

Investigators have been focusing on the possibility that the crash was caused by the way the crew responded to a jam in a “trim” mechanism that controls the movement of the stabilizer.

All 88 people aboard Flight 261 died in the crash, which was roughly between Oxnard and the Channel Islands. The plane was en route from Puerto Vallarta, Mexico, to San Francisco and Seattle.

Although the FBI has been involved in the crash investigation from the start, there is no indication that authorities suspect terrorism.

News of the two bangs was contained in a statement by NTSB investigators who have been listening to the cockpit voice recorder recovered earlier in the week. Hammerschmidt read a statement from the investigators at a news briefing in Port Hueneme after warning reporters that he wouldn’t answer questions about it--”and you will have questions.”

Reading from the statement, Hammerschmidt said: “Approximately 12 minutes before the end of the recording, the airplane experienced an apparent loss of vertical control”--a dive. “The crew recovered from this condition in approximately 1 1/2 minutes.”

After the plane had pulled out of the dive, he said, “a flight attendant advised the crew that she had heard a loud noise in the rear of the aircraft. The crew acknowledged that they had heard it too.” This last statement--that the bang in the rear of the plane could be heard in the cabin--suggests the sound was extremely loud to have been heard over the roar of the engines.

Finally, Hammerschmidt said, “Slightly more than one minute before the end of the recording, a loud noise can be heard on the recording and the airplane appears to go out of control.”

Investigators had previously said the plane was observed plunging in a corkscrew pattern into the sea.

Its remains lie in pieces, on hard-packed sand about 700 feet under the surface, settled within a remarkably compact area about the size of a football field, Hammerschmidt said.

The compact debris field is a huge advantage to investigators, particularly in comparison to other recent oceanic crashes. The wreckage of TWA Flight 800, for instance, was scattered over miles of the Atlantic Ocean floor off Long Island, N.Y.

On the other hand, the Alaska Airlines plane landed in relatively deep water, making recovery of the wreckage time-consuming and expensive, and virtually ruling out the use of human divers. The Navy, which is handling any recovery, must rely exclusively on remotely controlled underwater robots.

Among the jobs now facing the safety agency will be building a computerized, second-by-second record of the flight from voice and data recorders, radar records and interviews with air controllers, as well as inspecting and perhaps recovering key portions of the plane.

Although no decision has been announced, NTSB officials have suggested privately that they are unlikely to undertake the sort of massive reconstruction of the plane that was done after the TWA Flight 800 crash.

NTSB analysts have begun poring over information obtained from the flight data recorder, which kept track of 48 aspects of the flight. The recorder, which was in good condition, has information covering the entire two hours and 45 minutes of the flight, Hammerschmidt said.

Among the routine tasks ahead is a “human performance investigation” to evaluate how the cockpit crew responded to the emergency. Investigators will study the background of the two pilots, their history of flying and scores on flight tests, and interview pilots and other aviation officials who knew them.

There has been no hint so far that pilot error might have caused the crash. NTSB officials have said, however, that it is possible that the prescribed procedures followed by the pilots could have led to the crash, and NTSB Chairman Jim Hall has promised a review of those procedures.

The head of the Los Angeles chapter of the National Air Traffic Controllers Assn. described the captain and co-captain of the flight, Ted Thompson and William Tansky, as “heroes,” who had “acted in an extremely professional manner.”

“It was an extremely courageous move to stay over water and not endanger more lives over land with an aircraft that could not be controlled,” Hamid Ghaffari added in a letter to the families of the crash victims.

Ghaffari said he prepared his remarks to be read to a gathering of 150 relatives and friends of the crash victims Thursday night, but was unable to deliver them.

About 200 relatives and friends of the crash victims have been staying in hotels in Ventura County and Los Angeles, keeping a close eye on the investigation and participating in several memorial events, including a beachfront vigil and a boat trip to the accident site.

* NAVY SUBMERSIBLES

Underwater robots are eyes, ears and hands of teams seeking clues in the air crash. A16

* GRIEF COUNSELING

Clergy who aid the bereaved have been tested this week. B2

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

What Transcripts Show

No. 1: The first conversations involve communications between the flight crew and Alaska Airlines maintenance facility personnel in Seattle regarding the stabilizer trim.

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No. 2: About 12 minutes before the crash, the airplane experienced an apparent loss of vertical control, but recovered in about 90 seconds.

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No. 3: After this loss of vertical control, a flight attendant told the crew that she had heard a loud noise in the rear of the aircraft. The crew also heard it.

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No. 4: Slightly more than one minute before the end of the recording, a loud noise can be heard on the recording and the airplane seems to go out of control.

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Source: National Transportation Safety Board

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