Alaska disputes report on jackscrew test

Posted: Wednesday, May 24, 2000

SEATTLE (AP) -- Alaska Airlines is disputing a newspaper report that a jet was returned to service after a maintenance crew found a part fell just a thousandth of an inch shy of requiring close monitoring. The part in question is under investigation in the January 31 crash of Alaska Flight 261, in which all 88 aboard died.

The disputed report appeared in Sunday editions of The Seattle Times and cited information from an Alaska maintenance manual.

''Nowhere in Alaska's MD-80 maintenance manual is there any reference to the citation that The Times story hinges on,'' the airline said in a news release posted to its Web site Monday.

''In fact, the maintenance procedures and intervals that were followed by Alaska mechanics were developed by the aircraft manufacturer and approved or accepted by the Federal Aviation Administration,'' the airline said.

Flight 261 was en route to San Francisco from Puerto Vallarta when it crashed into the Pacific Ocean just off Los Angeles.

The pilots on the flight had reported problems with the plane's horizontal stabilizer, a flap on the tail which is tilted by the jackscrew assembly to change the pitch of the aircraft.

According to The Times, maintenance crews inspecting the plane in 1997 had recommended the jackscrew assembly be replaced after finding it was close to its maximum wear limit of .040 inches. Instead, The Times said, a directive to reevaluate the finding was issued, the part was found -- after six more tests -- to be less worn, and the plane was returned to service.

The crux of The Times' story was that the remeasured part -- at .033 inches of deterioration -- was less than a hair's breadth from requiring much closer scrutiny than it subsequently got. At .034 inches of wear -- just .001 inch more -- the part is to be rechecked after every 1,000 flight hours, The Times said, citing the maintenance manual.

That test result has become the focus of a criminal investigation of the airline's maintenance practices by the FBI and the Department of Transportation's inspector general, both of which are trying to determine if the test result was fudged, The Times said.

On Monday, Alaska said the issue may turn on the fact that there is more than one set of MD-80 maintenance requirements.

''The Times may be quoting a revised maintenance procedure that went into effect after the accident when the FAA issued an airworthiness directive requiring more frequent inspections of MD-80 jackscrews,'' the airline said.

''Or The Times could be quoting part of an overhaul manual that applies to overhauled parts being reinstalled on the aircraft. The jackscrew on the aircraft involved in the Flight 261 tragedy, however, was the original part, not an overhauled one,'' the airline said.

Citing federal officials familiar with the criminal investigation, The Times said Wednesday that the .034 standard was in place in 1997. It also cited a longtime Alaska mechanic as saying that an aircraft overhaul manual includes the .034 standard, but a separate ''component'' manual requires a less rigid standard.

The mechanic, who was not named, told The Times the aircraft overhaul manual would have been applicable during the 1997 tests, because the plane was undergoing a heavy maintenance, or ''C'' check. The overhaul manual also would have applied because of the initial decision to replace the part, the mechanic said.

The Los Angeles Times on Monday reported that Alaska mechanics said they were pressured to return jets to service in recent years despite inspections that found further repairs were necessary. None of those allegations involved Flight 261, however. Company officials have maintained their inspection and repair practices are safe.

Subscribe to Peninsula Clarion

Trending this week:


© 2018. All Rights Reserved. | Contact Us