B767-300 and 300 ER
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Aircraft
Stall Warning Event Mel's: Thrust Management System/Autothrottle System Inoperative/EEC Inoperative Event Occurred at FL370 .78 mach; aircraft weight approximately 311;000/SAT -45/cruise N1~95%. Crew positions: Relief Pilot (FB) in left hand seat/First Officer (FO) in right hand seat [and] Captain on rest break in crew seat. Flight conditions clear with light chop. Crew first alerted to an approach to stall condition was onset of stick shaker. Upon recognition; FB and FO Immediately initiated The Approach to Stall Maneuver. FO gained radio clearance to descend to FL350. FB descended and leveled at FL350. Capt felt/recognized unexpected change of altitude and returned to Flt Deck. Flight continued to destination without further incident. Flight crews must always remain vigilant in performance of their duties to prevent complacency that can result in this type of event; especially on long flights with inoperative systems.
Stall warning event. First alerted to approach to stall condition was onset of stick shaker. Relief Pilot (FB) and I (First Officer) immediately initiated approach to stall maneuver as I received clearance to descend to FL350. FB descended and leveled off at FL350. Captain felt an unexpected descent and returned to flight deck. Flight continued to destination without further incident. There were 3 MEL's. The thrust management system; the EEC's; and the autothrottles were all inoperative. The N1 was set for a Mach .78 cruise which was 95.0 N1. The event happened at FL370. Aircraft weighed approximately 311;000 LBS and the SAT was -45. Weather was clear and light chop. The event occurred during a frequency change where we could not establish contact on our given frequency. We were in the midst of trying to establish contact when the event happened. I went back to previous freq and received clearance to descend. The FB was in the left seat (pilot flying); I was in the right seat (pilot not flying); and the CPT was on his rest break. I had flown an aircraft a few days before that had the same MEL's. We set the N1 to our cruise Mach and had no problem. I think that led to me being complacent. We had looked at all the charts. We were well within the operating envelope for weight; temperature; and altitude and we got behind because we let the airspeed bleed off. Just because an N1 is set doesn't mean it is going to maintain that airspeed. A lesson I learned the hard way.
B767 flight crew experiences a stall warning at FL370 after being dispatched with an inoperative autothrust system. Recovery is initiated and a descent to FL350 is requested.