B757-200
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
Possible flaps 1 takeoff. PM reported after clean up; we may have had flaps 1 for departure vice normal flaps 5 setting. During the before takeoff checklist PF checked flap indicator and believed to have seen flaps appropriately configured at flaps 5. Rotation seemed normal with no indication of tail strike during liftoff. Rotation was easy; aircraft flew off ground normally.Performance parameters:V1 139VR 143V2 146Rotation occurred approximately 147 kts nose attitude approximately 8 degrees pitch. I still find it difficult to believe I missed this during the before takeoff checks. Possible expectation bias. Make sure aircraft is configured appropriately during before takeoff checks.
Possible fatigue-related error. Leg 2 of 2. About 13 hours since initial wake up. Aircraft show; walk-around; pre-flight; pushback; start and taxi were uneventful. Timing was methodical. At no time did I feel rushed.
B757-200 flight crew reported may have taken off with flaps 1 instead of the planned and calculated flaps 5.