Narrative:

On the long-delayed flight our crew experienced an altitude deviation while on a random route in oceanic airspace. Backing up in time to what I believe is a major contributing factor to the event; the crew desk apparently attempted to call our rooms multiple times in the very early morning hours in an attempt to reset our rest. I did not answer my phone until my scheduled wakeup time around 9 am local; at which time the crew desk informed me that my rest had been 'reset'. I was now wide awake; and unable to obtain additional rest that day before reporting for duty. Next; at the airport we encountered a weight-limited takeoff; requiring departure from an unfamiliar runway and associated SID adding to our workload; but we briefed as a team; and agreed that this flight's very late departure would be a threat we would manage together by taking our time. In spite of what we considered an irregular operation; the captain led the crew effectively at all times; encouraging input; not rushing and using all resources to ensure a safe departure. The international relief officer was extremely helpful during the busy preflight; pushback; taxi and departure. The flight continued uneventfully until the altitude deviation; which occurred in an attempt to escape continuous moderate turbulence.though not on the flight deck at the time of the deviation as I was on my scheduled rest break; I believe that this event's genesis can be traced back to the multiple phone calls each crew member received which I believe was in clear violation of the FAA's 'one-phone call policy'. The crew desk attempted to reach each of us in the very early morning hours that day to attempt a 'soft reset'. The flight was eventually delayed over 8 hours to show a 'legal' 10-hour rest reset; but effectively this ended up being an extremely long duty day; as I was unable to get additional rest after those calls. At report time however; I certified 'fit for duty'; as I felt ready; awake and alert (but perhaps unable to effectively assess how I would feel 11 hours later). I believe that this insidious effect of interrupted sleep on our collective decision-making abilities was a major contributing factor in the error the pilot flying and pilot monitoring made many hours later.

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Original NASA ASRS Text

Title: B767 flight crew reported experiencing fatigue that resulted in an altitude deviation during cruise.

Narrative: On the long-delayed flight our crew experienced an altitude deviation while on a random route in Oceanic Airspace. Backing up in time to what I believe is a major contributing factor to the event; the crew desk apparently attempted to call our rooms multiple times in the very early morning hours in an attempt to reset our rest. I did not answer my phone until my scheduled wakeup time around 9 am local; at which time the crew desk informed me that my rest had been 'reset'. I was now wide awake; and unable to obtain additional rest that day before reporting for duty. Next; at the airport we encountered a weight-limited takeoff; requiring departure from an unfamiliar runway and associated SID adding to our workload; but we briefed as a team; and agreed that this flight's very late departure would be a threat we would manage together by taking our time. In spite of what we considered an irregular operation; the Captain led the crew effectively at all times; encouraging input; not rushing and using all resources to ensure a safe departure. The IRO was extremely helpful during the busy preflight; pushback; taxi and departure. The flight continued uneventfully until the altitude deviation; which occurred in an attempt to escape continuous moderate turbulence.Though not on the flight deck at the time of the deviation as I was on my scheduled rest break; I believe that this event's genesis can be traced back to the multiple phone calls each crew member received which I believe was in clear violation of the FAA's 'one-phone call policy'. The Crew Desk attempted to reach each of us in the very early morning hours that day to attempt a 'soft reset'. The flight was eventually delayed over 8 hours to show a 'legal' 10-hour rest reset; but effectively this ended up being an extremely long duty day; as I was unable to get additional rest after those calls. At report time however; I certified 'Fit for Duty'; as I felt ready; awake and alert (but perhaps unable to effectively assess how I would feel 11 hours later). I believe that this insidious effect of interrupted sleep on our collective decision-making abilities was a major contributing factor in the error the Pilot Flying and Pilot Monitoring made many hours later.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.