Page 8 - 214744_December20T
P. 8

 Lessons in Leadership by Stan Dunn
 Exactly one month into the new millenni- um, Alaska Air flight 261 crashed into the Pacific Ocean off the coast of Los Angeles.
It was a scheduled international flight from Puerto Vallarta, Mexico, to Seattle-Tacoma Airport in Washington. There were two pilots, three cabin crew members and 83 passengers on board. There were no survivors.
The primary cause of the acci- dent was the failure of a jackscrew nut, which controlled the pitch trim for the MD-83 aircraft. Ultimately investigators would be convinced that the jackscrew in question had not been greased during at least two consecutive maintenance events. The NTSB would also fault signifi- cantly extended maintenance inter- vals on the jackscrew (which had been increased from 500 hours to 2,550 hours over an eight-year pe- riod), and point the finger at the FAA for lax oversight of Alaska Airline’s maintenance procedures.
These two issues would be joined by a third: End play checks indicated unusually rapid wear to the accident air- craft’s jackscrew more than a year prior to the crash. The mechanic who performed the end play check stated that
6 • TWIN & TURBINE / December 2020
he had never witnessed a jackscrew in such a worn state. As a result, he submitted a work order to replace the com- ponent. This was where – a year later – the NTSB would become perturbed with Alaska Airlines. A graveyard shift mechanic would cross out the work order to replace the jackscrew and instead remeasure the end play five separate times to verify it was within minimum wear limits (it had .007 inches to spare). The aircraft was unceremoniously returned to service.
Only a Matter of Time
Hidden in the tail of the aircraft was a rather large screw spinning through an unlubricated nut. Every second of horizontal trim chafed another mil- lionth of an inch of thread. By the time of the accident, the pitch trim system had been a ticking time bomb for weeks. The initial failure occurred in the climb with the autopilot on. Eventually, eleva- tor forces would cause the autopilot to disconnect. The crew would continue the climb for the next seven minutes through sheer endurance – up to 50 pounds of elevator force was required to maintain pitch attitude.
The cockpit voice recorder only captured the final 31 minutes of the flight, so there is no record of what the crew was doing while they were over Mexico. Undoubtedly, they ran the “Stabilizer Inoperative” checklist. They paused at an
    A common trait in effective leaders is the ability to be decisive. Imperfect decisions made decisively almost always produce better results.

   6   7   8   9   10