Alaska Air Crash Hearing Focuses on Jackscrew

W A S H I N G T O N, Dec. 14 -- The tail jackscrew that helps to stabilize anaircraft was the focus of attention today as engineers andinspectors offered their ideas on what caused the fatal plunge ofAlaska Airlines Flight 261 into the Pacific Ocean.

Mike O’Neil, a Federal Aviation Administration engineer fromLong Beach, Calif., testified the jackscrew was found with littlegrease on it but that other considerations such as “fatigue”limits and maintenance history were not critical factors.

“The jackscrew assembly … had exhibited an acceptable servicerecord,” he told a hearing before the National TransportationSafety Board. And when the part from the crashed plane wasrecovered, he said, “there was very little evidence of lubricanton the assembly, on the jackscrew itself.”

Testifying on the second day of what is expected to be afour-day hearing, O’Neil dodged a direct question on whether theentire horizontal stabilizer system that includes the jackscrew issafe for DC-9/MD-80 planes. He would say only that it“demonstrates compliance” with federal safety regulations.

Richard Rodriguez, the NTSB investigator in charge, notedWednesday “that Alaska Airlines was the only major operator in theUnited States that was using Aeroshell 33 to lubricate thejackscrews in their fleet.” Aeroshell 33 was developed to BoeingCo.’s specifications, he said.

Looking for CluesA sample jackscrew was prominently displayed in the entrancehallway outside the NTSB public boardroom.

On Wednesday, investigators released a series of reports thatincluded pictures of a damaged jackscrew and the rivetingtranscript of the cockpit voice recorder, a dramatic re-enactmentof the plane’s final moments.

It reflected how pilot Ted Thompson and co-pilot William Tanskyovercame one nose dive, only to fight their fatal second descentuntil the crash off California that killed all 88 people aboard.

The NTSB will not determine the cause of the accident until itcompletes its hearing, but much of the information so far isfocused on problems with the jackscrew, and grease applied to it.The part controls the DC-9/MD-80 horizontal stabilizer system.