What was found
RECEIVED APU FIRE WARNING AND APU FIRE DET FAIL AT 12,000 FEET, FIRED APU EXTINGUISHER BOTTLE, POST INSPECTION FOUND NO EVIDENCE OF FIRE. ISSUED AMERICAN EAGLE MEL 26-01, 26-05 AND 49-01. REPLACED FIRE BOTTLE IAW AMERICAN EAGLE WORK CARD 26-200-01. RESTORED MEL, RETURNED AIRCRAFT TO SERVICE.