>>5698483 pb

Another aircraft crash with jackscrew issues

https://www.seattletimes.com/seattle-news/10th-anniversary-of-alaska-flight-261/

In the minutes before the crash, the two pilots reported problems with the MD-83’s tail-section horizontal stabilizer, which controls the plane’s up-and-down movements. The stabilizer is operated by a component called the jackscrew, which consists of a nut that rides up and down a screw as it turns to raise and lower the stabilizer.

Two years earlier, John Liotine, a lead mechanic at Alaska Airline’s Oakland facility, had found that the jackscrew on the same aircraft was worn out. He ordered it replaced. But the plane was back in service within a few days without Liotine’s work order

Liotine went to federal authorities in late 1998 claiming the airline was cutting back on maintenance and falsifying inspection records and work orders to get planes back into operation faster.

After the crash, Alaska said Liotine’s work order had not been acted upon because a second inspection team had retested the approximately $80,000 jackscrew and found it was within the legal limits of wear.

In the plane’s wreckage, investigators found metal shavings indicating threads on the jackscrew had been stripped, causing the part’s failure.

When the jackscrew failed, the stabilizer no longer could keep the plane aloft. Flight 261 plunged into the ocean.