Alaska Airlines Crash Hearings Continue

A computer-generated warning that came too late. Paperwork not in order. Two types of greases mixed up and potentially corrosive.

These were among revelations surfacing Friday in a third day of increasingly pointed questioning by government investigators probing an Alaska Airlines jet crash that killed all 88 people aboard.

The National Transportation Safety Board is focusing on the airline's maintenance problems, particularly a 2½-foot-long jackscrew that helps control up-and-down movement in the tail section of the McDonnell Douglas MD-83 aircraft.

It also is examining the possibility that Boeing-approved grease may have corroded the jackscrew's threads. When the device snapped, it let the wing atop the tail swing out of control.

Boeing took over McDonnell Douglas in a 1997 merger.

Board members wonder whether the jackscrew's design is safe enough for the MD-80 family of jets. About 2,100 are in use, including the original DC-9 models.

Due to the large number of questions, the NTSB extended the hearing through Monday.

NTSB This jackscrew, nearly two feet long, has been tested extensively to try to determine whether the nut it screws into was damaged before or during the crash.

On Feb. 3, just three days after Flight 261 plunged into the Pacific Ocean off southern California, the airline's internal computer maintenance system issued "an alert notice" to check tail jackscrews in the entire fleet of airplanes, testified Wright McCartney, the airline's reliability manager.

"Unfortunately, it did not react in time to tip us off there may be a problem with the jackscrews" before the doomed flight, McCartney said Friday, although he added that the notice "in no way suggested the failure that occurred, or appeared to occur" on Flight 261.

Jackscrews are rarely replaced, the NTSB's Benjamin Berman said. A computer-generated analysis noticed Alaska Airlines' rate of replacement for jackscrews had reached 0.03 removals per 1,000-flight hours system-wide, the point at which an alert is issued, McCartney said.

Jim Davey, the airlines' assistant vice president for engineering, blamed a deceased former co-worker for incomplete paperwork approving a change in July 1997 in the type of grease used in the planes.

Davey said he nevertheless signed off on the change because it was felt that using a general-purpose grease "could lessen the chances for a mechanic to choose the wrong kind of grease."

At the time of the crash, Alaska Airlines was the only major U.S. airline using Aeroshell 33 to lubricate its planes' jackscrews, said Richard Rodriguez, te investigator in charge.

U.S. Navy tests on grease taken from the wrecked jackscrew found the Aeroshell 33 was "contaminated" with Mobil 28 and contained aluminum-bronze particles from a stripped 8-inch gimbal nut, said Dale Moore, who headed the testing at Patuxent River Naval Air Station in Maryland.

"Two incompatible greases should not be mixed because an inferior product could result," the Navy concluded in its report.

Boeing engineer Dennis Jerome acknowledged: "There may be a chemical reaction between the two greases."

The hearings seek to determine whether Flight 261 was brought down by a bad part, poor maintenance, a combination of both, or some other factor.

Testimony is focusing on a range of issues, including Alaska Airlines' maintenance procedures, its safety program, the design and service history of the MD-80 series aircraft, industry practice regarding lubrication of jackscrews, and Federal Aviation Administration surveillance of Alaska Airlines.

The hearings will also explore what the final, terrifying minutes of Flight 261 were like.

The NTSB will not determine the cause of the accident until it completes the public hearings and studies the investigative data and expert testimony.

The NTSB is expected to issue its final report sometime next year.