B757 Undifferentiated or Other Model
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 146; Flight Crew Total 16000
Fatigue; Situational Awareness
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
Flight Crew Became Reoriented
Company Policy; Human Factors; Staffing; Aircraft
Aircraft had a maintenance issue; the APU generator kept tripping off; and company finally decided to switch aircraft. We finally departed close to XA:00; about 1.5 hours before our duty CCO ran out. During the pre-departure brief we talked about the late hour and fatigue being a threat. Once we were in cruise flight we both felt very tired and talked about how we wished we had an IRO (International Relief Officer) so that we could get a break and some sleep. About 3-4 hours into the flight I accidentally nodded off. I am not sure how long I was asleep; but it was probably not more than 5-10 minutes. When I woke up; I noticed the First Officer had accidentally fallen asleep as well. Both pilots had fallen asleep at the controls! These late departures unaugmented are bad enough; but when you have a delay that lasts several hours; they are downright dangerous. Even if you feel OK at departure; you can 'crash' a few hours into the flight. I had taken a short nap about 5 hours before check-in; but was still very tired after take-off. Thankfully; nothing bad happened; but the potential for a dangerous situation was there.
B757 Captain reported that flight delays and fatigue caused him and the First Officer to fall asleep during flight.