FAA expects final results of stabilizer inspections Wednesday

The jackscrew from Alaska Airlines Flight 261, left and the gimbal nut

Problems reported on 27 planes so far

February 15, 2000
Web posted at: 11:22 p.m. EST (0422 GMT)

In this story: Number of problem planes may grow Where the trouble was found Pentagon reports no problems RELATED STORIES, SITES

From staff and wire reports

WASHINGTON (CNN) -- The Federal Aviation Administration says it should have a final tally Wednesday of how many MD-80 series jetliners failed inspections of their horizontal stabilizers, a part suspected to be the cause of the crash of Alaska Airlines Flight 261.

VIDEO CNN's Carl Rochelle reports on the maintenance record of the Alaska Airlines jet that crashed. (February 14) QuickTime Play Real 28K 80K Windows Media 28K 80K     INTERACTIVE RESOURCES Zoom in: How the MD-83 stabilizer works Timeline of recent crashes Flight 261 altitude data Image gallery: The crash of Flight 261 Flight 261 background Facts about Alaska Airlines     MESSAGE BOARD Alaska Airlines crash

The FAA said as of midday Tuesday it had received reports of 27 MD-80 series jetliners, operated by nine different airlines, with problems or potential problems in the jackscrew/gimbal nut assemblies. The assembly is used to drive a plane's horizontal stabilizer trim.

The pilots of Flight 261 complained of difficulties controlling the horizontal stabilizer of their MD-83 before it plunged into the Pacific Ocean near Los Angeles on January 31, killing all 88 people on board.

After voluntary inspections turned up problems in the tail sections of several planes, the FAA last Friday ordered all U.S. airlines to inspect the trim assemblies on the nearly 1,100 DC-9, MD-80, MD-90 and Boeing 717 aircraft within three days.

Number of problem planes may grow

Officials say they have received reports on all but about 140 so far. The inspections were to be completed by midday Monday, but airlines had up to 48 hours to report their findings, so the total of problem planes still may grow.

Problems reported so far range from a lack of jackscrew lubrication to metal slivers from the gimbal nut in the jackscrew grease.

Officials say 15 of the jackscrew assemblies were replaced, some because they were damaged, others as a precaution.

The questionable parts are being examined by FAA and National Transportation Safety Board officials to determine if further action is necessary.

Where the trouble was found

Alaska Airlines had the largest number of problem aircraft, with eight found to have metal shavings in the gimbal nut assembly.

Four of the assemblies were replaced, with the old ones now in the custody of the National Transportation Safety Board. Four other assemblies are still being evaluated.

Delta, which has 136 MD-80 series planes, had six on the problem list.

Three had a gritty residue in the jackscrew assembly; they were lubricated and returned to service. One plane that failed the "end plate" test had the jackscrew/gimbal nut assembly replaced before being returned to service. Two other aircraft were said to have potential problems with the jackscrew assembly.

AirTran found two planes with gritty residue, and one that failed the "end plate" test. The jackscrew assembly was replaced in all three.

Northwest replaced the assembly in all three planes that it found with problems.

Continental, American and TWA, each of which found one plane with a problem or potential problem, replaced the assembly as well.

Hawaii Airlines found two assemblies with metal shavings and replaced both.

Airborne Express found two planes that needed relubrication; the procedure was performed, and the planes were returned to service.

Pentagon reports no problems

Pentagon officials said Tuesday that all their military aircraft similar to the MD-80 series have passed inspections of the assemblies.

The Air Force, the Marine Corps and the Navy all fly a variant of the DC-9 aircraft. The services use the C-9s to fly people and cargo as well as for medivac purposes.

"The inspections of all 52 of those aircraft have been completed, and we have not found any abnormalities or failures in those assemblies," said Defense Department Spokesman Rear Adm. Craig Quigley.

Correspondent Carl Rochelle and Reuters contributed to this report.

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