Narrative:

After pushback during #1 engine start we got APU detection inoperative light on. Shut down APU -- checked irregular procedure. Notified psp operations told them to contact maintenance. I had flown into psp before and I knew I couldn't reach maintenance through commercial radio on ground. I told operations we'd contact maintenance airborne. We started #2 engine through xbleed. Taxied out, completed checklist. On takeoff roll, approximately 80 KTS we got an APU fire warning (fire bell and light in handle). Captain aborted takeoff. First officer pulled APU fire handle and shot fire bottle. Notified tower of abort and called for fire trucks. Both tower and fire crews reported no smoke or visible fire. Return aircraft to gate -- deplaned people, notified maintenance, dispatch through operations telephone. Mechanic found APU detection wire pinched -- giving false warning. Cleared aircraft through maintenance to continue to den with APU inoperative. On reviewing incident, I should have waited on ground to get maintenance clearance with APU inoperative. Problem is crews normally shut down APU after engine start, as a habit. However, with APU detection inoperative, we needed maintenance clearance. I knew I could not reach maintenance through commercial radio but I should have used other methods. (Ie, waited for operations to relay.) trying to keep on schedule was also a factor.

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Original NASA ASRS Text

Title: B737-300 HAD A FALSE APU FIRE WARNING AT THE GATE. APU WAS SHUT DOWN AND ACFT DEPARTED WITH APU SHUT DOWN. DEFERRAL WAS NOT OBTAINED FROM MAINT. LATER, DURING TKOF, ANOTHER FALSE WARNING WAS RECEIVED. TKOF ABORTED AND RETURNED TO THE GATE. A PINCHED WIRE WAS FOUND IN THE FIRE WARNING CIRCUIT.

Narrative: AFTER PUSHBACK DURING #1 ENG START WE GOT APU DETECTION INOP LIGHT ON. SHUT DOWN APU -- CHKED IRREGULAR PROC. NOTIFIED PSP OPS TOLD THEM TO CONTACT MAINT. I HAD FLOWN INTO PSP BEFORE AND I KNEW I COULDN'T REACH MAINT THROUGH COMMERCIAL RADIO ON GND. I TOLD OPS WE'D CONTACT MAINT AIRBORNE. WE STARTED #2 ENG THROUGH XBLEED. TAXIED OUT, COMPLETED CHKLIST. ON TKOF ROLL, APPROX 80 KTS WE GOT AN APU FIRE WARNING (FIRE BELL AND LIGHT IN HANDLE). CAPT ABORTED TKOF. FO PULLED APU FIRE HANDLE AND SHOT FIRE BOTTLE. NOTIFIED TWR OF ABORT AND CALLED FOR FIRE TRUCKS. BOTH TWR AND FIRE CREWS RPTED NO SMOKE OR VISIBLE FIRE. RETURN ACFT TO GATE -- DEPLANED PEOPLE, NOTIFIED MAINT, DISPATCH THROUGH OPS TELEPHONE. MECH FOUND APU DETECTION WIRE PINCHED -- GIVING FALSE WARNING. CLRED ACFT THROUGH MAINT TO CONTINUE TO DEN WITH APU INOP. ON REVIEWING INCIDENT, I SHOULD HAVE WAITED ON GND TO GET MAINT CLRNC WITH APU INOP. PROB IS CREWS NORMALLY SHUT DOWN APU AFTER ENG START, AS A HABIT. HOWEVER, WITH APU DETECTION INOP, WE NEEDED MAINT CLRNC. I KNEW I COULD NOT REACH MAINT THROUGH COMMERCIAL RADIO BUT I SHOULD HAVE USED OTHER METHODS. (IE, WAITED FOR OPS TO RELAY.) TRYING TO KEEP ON SCHEDULE WAS ALSO A FACTOR.

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.