FAA Lowers Jet Problem Count to 5

Revised figures released by the Federal Aviation Administration on Friday showed that far fewer planes than originally reported had problems like those found in the Alaska Airlines jet that crashed Jan. 31.

The FAA had reported Monday that on 15 planes--five of them flown by Alaska--metal slivers were found in the horizontal stabilizer actuator mechanisms. But the agency said Friday that further examination showed the slivers to be present on only five planes, one of them from Alaska.

In some cases, the downward revisions resulted from redefinition: What originally had been described as slivers was redefined as “gritty grease.” In other cases, problems were simply downgraded to “normal wear and tear.”

The FAA said 1,098 DC-9, MD-80 series, MD-90 series and Boeing 717 jetliners have been inspected under the mandate handed down last week after concerns were raised during a check of the stabilizer mechanisms on two Alaska jets after the crash.

National Transportation Safety Board investigators said the slivers were found in the stabilizer mechanism of the MD-83 that crashed into the ocean near Anacapa Island, killing all 88 on board.

The slivers apparently had been stripped from the gimbal nut on the stabilizer’s jackscrew--a thick, threaded bolt about two feet long. The jackscrew moves the stabilizer--the wing-like part of the tail that largely controls the up-and-down pitch of the plane’s nose. What stripped the threads is not known.

The NTSB said Sunday that during a regularly scheduled check in 1997, Alaska’s maintenance personnel in Oakland found that the jackscrew mechanism on the plane that would crash was so worn that they briefly considered replacing it. However, in rechecking the mechanism five times, they decided the wear was within specified tolerances and left it on the plane. The mechanism was not checked again before the crash. The pilots of Alaska’s Flight 261 reported problems with the stabilizer, and the mechanism apparently jammed about 12 minutes before the crash.

The revised figures issued Friday showed that the inspections ordered last week turned up metal slivers in the stabilizer jackscrew mechanism on one Alaska plane, two planes flown by Hawaiian Airlines and one plane each from Northwest Airlines and Trans World Airlines.

In addition, problems relating to gritty grease, improper tolerances and a damaged jackscrew-limiting device were found in the stabilizer mechanisms of a total of 17 planes flown by AirTran, Alaska, Delta Air Lines, Hawaiian, Northwest and Reliant Airlines.

The FAA ordered Friday that the mechanisms be checked after every 650 flight hours. Previously, the checks were required only after every 6,500 flight hours.

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Problems Found on 22 Inspected Planes

The following is an updated rundown of problems found during airplane inspections ordered on 1,107 planes after the Jan. 31 crash of Alaska Airlines Flight 261. The FAA said 1,098 inspections have been performed; problems were found on 22 planes. Nine more planes that already were out of service will be inspected before they fly again.

AirTran: Three jackscrews replaced; two had gritty grease, one had a jackscrew mechanism with a poor fit.

Alaska Airlines: Six jackscrews replaced; five had jackscrew mechanisms with a poor fit, one had metal shavings.

Delta Air Lines: Four jackscrews with gritty grease were lubricated; one was replaced.

Hawaiian Airlines: Three jackscrews replaced; two had shavings, one had a jackscrew mechanism with a poor fit.

Northwest Airlines: Three jackscrews replaced; two had gritty grease, one had shavings.

Reliant: One jackscrew replaced; it had a damaged limiting device.

TWA: One jackscrew replaced; it had shavings.