Narrative:

I have flown the beijing trip from ZZZ many; many times prior to the trip being reduced from 4 days to 3. I never felt undue fatigue during the flight; at least not due to inadequate rest during the layover. However; while flying this new 3 day schedule it wasn't long after takeoff from beijing that I felt fatigued; and this fatigue worsened as the flight went on. I was the flying first officer and had the first working shift. Not long after leveloff I felt the constant need for a nap and had to fight continuously to stay awake. This is probably because as usual; I awoke at XA00 am in the morning of the flight and was unable to get back to sleep. Normally this would not be a problem because I would have the entire day to find additional time to sleep. Usually the 2ND night I sleep straight through and am refreshed enough to feel ok for the flight back to ZZZ. With the new 3 day trip; I didn't have that opportunity and it could have caused an unsafe situation. Although all the flight crew commented on the short layover and associated lack of sleep; none of us thought we would feel so whipped so early into the flight. Even after spending 4 1/2 hours in the bunk I felt very tired during the descent and approach. The bottom line is: next time I feel fatigued prior to departure time; and I'm the flying first officer; I will decline to fly. I know this will adversely affect the company's performance; but the company obviously doesn't feel concerned about fatigued crews and the effect on the safe conduct of the flight.

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Original NASA ASRS Text

Title: B747-400 PLT RPTS THAT HE WAS FATIGUED.

Narrative: I HAVE FLOWN THE BEIJING TRIP FROM ZZZ MANY; MANY TIMES PRIOR TO THE TRIP BEING REDUCED FROM 4 DAYS TO 3. I NEVER FELT UNDUE FATIGUE DURING THE FLT; AT LEAST NOT DUE TO INADEQUATE REST DURING THE LAYOVER. HOWEVER; WHILE FLYING THIS NEW 3 DAY SCHEDULE IT WASN'T LONG AFTER TKOF FROM BEIJING THAT I FELT FATIGUED; AND THIS FATIGUE WORSENED AS THE FLT WENT ON. I WAS THE FLYING FO AND HAD THE FIRST WORKING SHIFT. NOT LONG AFTER LEVELOFF I FELT THE CONSTANT NEED FOR A NAP AND HAD TO FIGHT CONTINUOUSLY TO STAY AWAKE. THIS IS PROBABLY BECAUSE AS USUAL; I AWOKE AT XA00 AM IN THE MORNING OF THE FLT AND WAS UNABLE TO GET BACK TO SLEEP. NORMALLY THIS WOULD NOT BE A PROB BECAUSE I WOULD HAVE THE ENTIRE DAY TO FIND ADDITIONAL TIME TO SLEEP. USUALLY THE 2ND NIGHT I SLEEP STRAIGHT THROUGH AND AM REFRESHED ENOUGH TO FEEL OK FOR THE FLT BACK TO ZZZ. WITH THE NEW 3 DAY TRIP; I DIDN'T HAVE THAT OPPORTUNITY AND IT COULD HAVE CAUSED AN UNSAFE SITUATION. ALTHOUGH ALL THE FLT CREW COMMENTED ON THE SHORT LAYOVER AND ASSOCIATED LACK OF SLEEP; NONE OF US THOUGHT WE WOULD FEEL SO WHIPPED SO EARLY INTO THE FLT. EVEN AFTER SPENDING 4 1/2 HRS IN THE BUNK I FELT VERY TIRED DURING THE DSCNT AND APCH. THE BOTTOM LINE IS: NEXT TIME I FEEL FATIGUED PRIOR TO DEP TIME; AND I'M THE FLYING FO; I WILL DECLINE TO FLY. I KNOW THIS WILL ADVERSELY AFFECT THE COMPANY'S PERFORMANCE; BUT THE COMPANY OBVIOUSLY DOESN'T FEEL CONCERNED ABOUT FATIGUED CREWS AND THE EFFECT ON THE SAFE CONDUCT OF THE FLT.

Data retrieved from NASA's ASRS site as of January 2009 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.