NTSB Identification: LAX02IA002.
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Scheduled 14 CFR Alaska Airlines, Inc.
Incident occurred Wednesday, October 10, 2001 in Santa Ana, CA
Probable Cause Approval Date: 05/30/2006
Aircraft: Boeing 737-700, registration: N615AS
Injuries: 87 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
The flight crew experienced a jammed horizontal stabilizer trim actuator during the takeoff initial climb. The pilot reported that after takeoff, during climb out, the "STAB OUT OF TRIM" annunciator light illuminated. The crew disengaged the autopilot and found the electric trim control inoperative at both the pilot and co-pilot positions, and the manual trim control was jammed and immovable. The crew leveled the airplane at 13,000 feet and accomplished the "Stabilizer Out of Trim" and "Jammed Stabilizer" checklists to no avail. The crew declared an emergency with air traffic control, and made an otherwise uneventful landing at Los Angeles. According to the pilot, the trim manual control was jammed and immobile. Post flight examination revealed the horizontal stabilizer trim actuator motor was seized. The actuator motor was subsequently replaced with a serviceable unit, and the aircraft was ferried to Seattle for inspection. No other faults were found in the pitch trim system and the airplane was returned to service. Further examination of the actuator motor revealed that the motor was mechanically seized. According to a representative of Boeing Aircraft Company, with the motor seized, in order to manually trim the stabilizer, it would have been necessary for the flight crew to exert sufficient force on the trim wheel to cause the motor clutch to slip in addition to the force necessary to overcome normal system friction.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: The failure of the stabilizer electric trim motor as a result of internal mechanical seizure. Full narrative available
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