Narrative:

We had a master warning/tail compartment light at liftoff. We were given an unexpectedly quick cleared for takeoff while we still had an engine shut down. As we took the runway we started #2 and shut down the APU and completed the checklist. Due to the automatic 1 min cool-down cycle on the APU, it probably did not shut down until about liftoff. At liftoff the above lights came on intermittently, so we went through the immediate procedures, shutting the high pressure bleed off and making sure the pneumatic xfeeds were closed and the anti-ice was off. The light went out for good and we checked our QRH. It said the flight could continue at the captain's discretion. We had a 4 hour flight with a possible front to cross, which might need anti-ice. Since the light was never on steady and the APU was late being shut down, I was pretty sure the APU was the problem. I elected to turn the anti-ice and hp bleed on to verify that it was the APU. After 2 mins the light came on and we shut everything back off and made an overweight landing. In retrospect I never thought I was doing anything unsafe, because I thought I knew what was wrong. However, I probably should not have considered the note in the QRH about continuing the flight and just returned after I got the light out the first time.

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Original NASA ASRS Text

Title: APU COMPARTMENT OVERHEAT LIGHT WAS INTERMITTENT, BUT ON FURTHER TESTING STAYED ON. FLT RETURNED AND LANDED OVERWEIGHT.

Narrative: WE HAD A MASTER WARNING/TAIL COMPARTMENT LIGHT AT LIFTOFF. WE WERE GIVEN AN UNEXPECTEDLY QUICK CLRED FOR TKOF WHILE WE STILL HAD AN ENG SHUT DOWN. AS WE TOOK THE RWY WE STARTED #2 AND SHUT DOWN THE APU AND COMPLETED THE CHKLIST. DUE TO THE AUTOMATIC 1 MIN COOL-DOWN CYCLE ON THE APU, IT PROBABLY DID NOT SHUT DOWN UNTIL ABOUT LIFTOFF. AT LIFTOFF THE ABOVE LIGHTS CAME ON INTERMITTENTLY, SO WE WENT THROUGH THE IMMEDIATE PROCS, SHUTTING THE HIGH PRESSURE BLEED OFF AND MAKING SURE THE PNEUMATIC XFEEDS WERE CLOSED AND THE ANTI-ICE WAS OFF. THE LIGHT WENT OUT FOR GOOD AND WE CHKED OUR QRH. IT SAID THE FLT COULD CONTINUE AT THE CAPT'S DISCRETION. WE HAD A 4 HR FLT WITH A POSSIBLE FRONT TO CROSS, WHICH MIGHT NEED ANTI-ICE. SINCE THE LIGHT WAS NEVER ON STEADY AND THE APU WAS LATE BEING SHUT DOWN, I WAS PRETTY SURE THE APU WAS THE PROB. I ELECTED TO TURN THE ANTI-ICE AND HP BLEED ON TO VERIFY THAT IT WAS THE APU. AFTER 2 MINS THE LIGHT CAME ON AND WE SHUT EVERYTHING BACK OFF AND MADE AN OVERWT LNDG. IN RETROSPECT I NEVER THOUGHT I WAS DOING ANYTHING UNSAFE, BECAUSE I THOUGHT I KNEW WHAT WAS WRONG. HOWEVER, I PROBABLY SHOULD NOT HAVE CONSIDERED THE NOTE IN THE QRH ABOUT CONTINUING THE FLT AND JUST RETURNED AFTER I GOT THE LIGHT OUT THE FIRST TIME.

Data retrieved from NASA's ASRS site as of July 2007 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.