The crew of a Trans World Airlines Boeing 727 that rolled and dived more than five miles in 20 or 30 harrowing seconds over Michigan last April charged today that federal investigators are attempting to blame them for the incident without proof.
The charge came in a prepared statement read to the media by J. Scott Kennedy, the copilot, just before he testified at a deposition taking the National Transportation Safety Board held here to clarify conflicting accounts of what crew members were doing shortly before the incident occurred.
Knowledgeable federal officials have told The Washington Post that technical studies show there is no way the incident could have happened without some action in the cockpit.
Furthermore, nowhere in the crew's statement did Kennedy specifically deny crew involvement, although a representative of the Air Line Pilots Association (ALPA) did so later in response to a reporter's question.
A draft safety board report states that the flight-control action that led to the start of the incident may have been "commanded by the flight crew."
That conclusion, while not formally adopted, was reached through the process of elimination by the board's technical staff after 118 flight simulations and flight and wind-tunnel tests conducted under board supervision at Boeing.
The deposition today was ordered to clear up a discrepancy between what pilot Harvey Gibson apparently told Federal Aviation Administration investigators in an informal interview shortly after the incident and what he testified to later in a formal deposition.
All 89 people on TWA flight 841 survived the incident last April 4. The Boeing 727 was en route from New York to Minneapolis It had just climbed to 39,000 feet, according to Gibson, when he felt a "buzzing," and the plane started to roll.
Board officials, after final studies, say the plane rolled over completely then started to roll again, at the same time going into a dive. Gibson regained control at 9,000 feet, after he lowered the landing gear, an extraordinary procedure.
Board investigators say they believe the rolling started because one slat, a large plate on the front of the wing that is normally extended only during takeoff and landing, was extended at that high altitude.
The controversy centers around the question of how the slat came to be extended. Was it a mechanical malfunction? Was it extended by the crew? The slat was torn off the wing during the rapid descent.
The board's staff says it believes the slats on the right wing must have been extended, then retracted, but that one slat did not retract. That has happened on other Boeing 727s in the past, but it has always been controllable, investigators say.
Simulator tests show that in this incident Gibson's 727 should have been controllable for 17 seconds before the roll would exceed the ability of the controls to overcome it.
Suspicions about crew involvement were strengthened the day after the incident when it was discovered that after the plane landed in Detroit the crew members had erased the recording of their cockpit conversations.
Today's deposition was taken to clarify the question of whether flight engineer Gary Banks had left the cockpit shortly before the incident began.
Banks insisted that he never left the cockpit. A flight attendant testified that Banks had left the cockpit to return the crew's dinner trays, but that he returned at least 30 minutes before the incident began. Gibson said he saw Banks return to his seat and that "I assume, [he had been gone] to return the trays." Earlier, in a report to the FAA, Gibson was quoted as saying that Banks returned just before the incident began.
Safety Board Chairman James B. King said in Washington late yesterday that the board will conduct more technical studies on the incident before issuing its final ruling of probable cause.