Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem; General Maintenance Action
Human Factors; Aircraft
As we were starting descent from FL400; with the autopilot and autothrottle on; the left thrust lever moved a little but then got stuck near cruise power setting and the autothrottle motor tried but was unable to move it back immediately causing an asymmetric thrust situation. The right thrust lever moved correctly and the Captain immediately noticed the problem. He attempted to disconnect the autothrottle using the button on the thrust lever and the switch on the MCP then manually tried pulling the left thrust lever; none of which fixed the problem. He asked me to try and it felt like the lever was moving slightly about an inch but would then spring back to the stuck position. Any movement of the thrust lever did affect the engine power however. I pulled harder and the thrust lever slammed to the idle position and had normal freedom of movement the remainder of the flight.The Mechanic found a notepad had fallen into the throttle quadrant and was interfering with the clutch microswitch and the clutch for the autothrottle.
When the left thrust lever of their B757-200 appeared to stick in place at cruise thrust as they started their descent the flight crew applied increasing leverage until it broke loose and functioned normally thereafter.  Maintenance found a notepad had slipped into the pedestal.