B737-700
Flight Crew Last 90 Days 141
Troubleshooting
Aircraft Equipment Problem Critical
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
First flight of the day; climbing out of approximately 12;000 FT with autothrottle ON and VNAV climb mode selected. We felt a 'mushy' yaw/roll/pitch change followed by a more pronounced yaw in the opposite direction. I noticed the number one engine had rolled back significantly to the mid 60% range. I assumed the number one engine had failed and disconnected the autothrottle and autopilot. I retarded the number one throttle toward idle and the engine appeared to stabilize. When the engine stabilized; no further abnormal indications were noted. The flight attendants reported hearing a 'pop' just before the event. We ran all checklists and returned to the departure airport. We elected to use flaps 15 for the landing. The remainder of the flight was uneventful. Upon shutdown; a red box appeared around the digital readout of the number one engine N1 indicating an exceedence. Dispatch; Maintenance; and the Chief Pilot were notified. A logbook entry was made.
A B737-700 engine rolled back in flight then stabilized; but after that the flight attendants reported a pop. The flight returned to the departure airport where engine instruments indicated an N1 exceedence.