Это на схемах? Вроде никаких муфт и сцеплений в приводе стаба нет.
просто гуглил.
The stabiliser trim wheels are mechanically connected through cables to the aft cable drum. When pilots turn the trim wheels, the aft cable drum turns a jackscrew through a gearbox. When the jackscrew turns, the stabiliser changes its pitch.
During electrical trim, stabiliser trim actuator (multi-speed DC motor powered by AC transfer bus 2) turns the jackscrew through the stabiliser gearbox. The actuator also back drives the stabiliser trim wheels (trim wheels move whenever jackscrew turns regardless of manual or electric operation).
The gearbox consists of two ratchet type brakes and mechanical clutch. The clutch lets the stabiliser manual trim wheel input override the stabiliser trim actuator input.
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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 controls 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. After conferring by radio with their company maintenance personnel at Los Angeles, the decision was made to land there. The crew declared an emergency with air traffic control and made an otherwise uneventful landing at Los Angeles. According to the pilot, maintenance personnel who met the airplane on arrival could not move the stabilizer control either and believed the actuator gearbox was jammed. In a subsequent company interview, on November 13, 2001, the pilot reiterated that the trim manual control had been jammed and immobile; neither he, the first officer (co-pilot) or the mechanics who met the flight, were able to force it to move.
The pilot said he had trained for the jammed stabilizer emergency in the simulator; however, in the incident at hand he had applied "a lot more force" than was required in the simulator and was still unable to move the manual control.
Post flight examination revealed the horizontal stabilizer trim actuator motor was seized. The actuator motor was 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 have exerted sufficient force on the trim wheel to cause the motor clutch to slip in addition to the force necessary to overcome normal system friction.
Event Details (fss.aero)