Narrative:

Normal preflight; taxi and takeoff were accomplished. Climbing out of FL300; the APU fire handle illuminated with the appropriate master caution warning and bell. Knowing the APU had been shut down since 5 mins before takeoff; we were reasonably certain it was a false indication. However; we ran the qrc which directed us to land. The cabin was prepped by the cabin crew; who also assessed for us that there was no perceivable indication of an APU fire in the cabin. We returned to ZZZ with fire department standing by. Upon landing; the tower said that there were no signs of a problem and this was confirmed by the fire department after we cleared the runway. We taxied to a gate and deplaned. All but 3 passenger re-boarded another aircraft; confident that we would get them to destination.

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Original NASA ASRS Text

Title: A B737-300 CLBING OUT OF FL300 DECLARED AN EMER DUE TO THE APU FIRE HANDLE ILLUMINATED WITH THE MASTER CAUTION AND BELL. RETURNED TO DEP ARPT.

Narrative: NORMAL PREFLT; TAXI AND TKOF WERE ACCOMPLISHED. CLBING OUT OF FL300; THE APU FIRE HANDLE ILLUMINATED WITH THE APPROPRIATE MASTER CAUTION WARNING AND BELL. KNOWING THE APU HAD BEEN SHUT DOWN SINCE 5 MINS BEFORE TKOF; WE WERE REASONABLY CERTAIN IT WAS A FALSE INDICATION. HOWEVER; WE RAN THE QRC WHICH DIRECTED US TO LAND. THE CABIN WAS PREPPED BY THE CABIN CREW; WHO ALSO ASSESSED FOR US THAT THERE WAS NO PERCEIVABLE INDICATION OF AN APU FIRE IN THE CABIN. WE RETURNED TO ZZZ WITH FIRE DEPT STANDING BY. UPON LNDG; THE TWR SAID THAT THERE WERE NO SIGNS OF A PROB AND THIS WAS CONFIRMED BY THE FIRE DEPT AFTER WE CLRED THE RWY. WE TAXIED TO A GATE AND DEPLANED. ALL BUT 3 PAX RE-BOARDED ANOTHER ACFT; CONFIDENT THAT WE WOULD GET THEM TO DEST.

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.