B757 Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 124; Flight Crew Total 19500; Flight Crew Type 11400
Troubleshooting; Workload; Time Pressure
Aircraft Equipment Problem Less Severe
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Procedure; Human Factors
This aircraft just came out of long term storage. It needed a full thrust takeoff; ETOPS verification for hi-altitude APU start and an Autoland update. Two separate Maintenance write-ups occurred after door close but prior to push back. This resulted in delays and multiple MRD updates. Both pilots reviewed and verified FMC load was normal after each anomaly corrected. On takeoff the FO (Flying Pilot) called for 'Autothrottles.' EPR mode engaged normally but throttles were slow to advance and left throttle lagged approximately 1 knob width. At 'check thrust' call FO commented to check left engine throttle. I had noticed the slow movement and manually moved both throttles to the commanded full thrust EPR setting. When passing 3;000 ft. the aircraft speed bug would not accelerate above CMS (approximately). We set 250 manually and each time we tried to engage VNAV or FLCH the command bug retreated to approximately CMS. We also noticed the command EPR was indicating CON thrust. I tried to engage CLB on TMSP panel but had no effect. At this point I said we'll wait until above 10;000 ft. to troubleshoot further. Above 10;000 ft I noticed that the VNAV CLB page appeared normal; but there was an 'ALL ENG' prompt at 5L which I'd never seen. After selecting the ALL ENG prompt the airplane returned to normal CLB mode. At no point during ground operations did either pilot ever select the CLB EO prompt or the subsequent Execute key. After landing and debriefing with Maintenance and the next leg's Captain; this Pilot stated she had also previously seen a 'split throttles on takeoff result in the aircraft believing it was in a single-engine situation and engaging the EO CLB mode. A Maintenance write up for Autothrottles was written up and Maintenance debriefed. (Autothrottles worked normal for remainder of our flight).
B-757 Captain reported aircraft being returned to service from long term storage suffered an auto throttle malfunction on climb out and subsequently learned that later flights had the same problem.