Narrative:

This leg is the second of a six day international flight crew schedule. It began with a 12 hour actual flight to japan followed by a layover involving two 1+20 cab rides to the downtown hotel and return. Rest at the hotel was optimal but the circadian wakeup of about 4AM japan time prevents actual preflight rest for the flight to singapore. The flight is un-augmented; all night; and begins around 2AM body clock time after an awake cycle of almost 16 hours.I was unable to maintain a useful wakefulness during the last two hours of the flight. I experienced subtle incapacitation from late cruise through descent and landing. I fell sound asleep on the bus to the hotel and had to be awakened upon arrival at the hotel. This un-augmented segment is dangerous!! We had minor weather deviations. Any major malfunction could lead to damage; even loss of life. I recommend that the flight be scheduled with augmentation or with pilots stationed in the time zone and more acclimated to the body clock required.

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Original NASA ASRS Text

Title: An international Captain described the circadian difficulties associated with a flight pairing from mainland USA to Japan and; following a layover; an un-augmented about 3;000 Nautical Mile all night flight to Singapore.

Narrative: This leg is the second of a six day international flight crew schedule. It began with a 12 hour actual flight to Japan followed by a layover involving two 1+20 cab rides to the downtown hotel and return. Rest at the hotel was optimal but the circadian wakeup of about 4AM Japan time prevents actual preflight rest for the flight to Singapore. The flight is un-augmented; all night; and begins around 2AM body clock time after an awake cycle of almost 16 hours.I was unable to maintain a useful wakefulness during the last two hours of the flight. I experienced subtle incapacitation from late cruise through descent and landing. I fell sound asleep on the bus to the hotel and had to be awakened upon arrival at the hotel. This un-augmented segment is DANGEROUS!! We had minor weather deviations. Any major malfunction could lead to damage; even LOSS OF LIFE. I recommend that the flight be scheduled with augmentation or with pilots stationed in the time zone and more acclimated to the body clock required.

Data retrieved from NASA's ASRS site as of April 2012 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.