What was found
ARRIVED AT GATE WITH APU RUNNING, TRANSFER BLEED NOTICED APU DOOR INHIBIT CLOSED AND RPM AT 76 PERCENT, SHUTDOWN APU AND RECEIVED APU FIRE FAIL CAUTION MESSAGE AFTER OBSERVING SMOKE AND FLAMES FROM APU EXHAUST AREA. PUSHED APU FIRE PUSH BUTTON AND APU BOTTLE BUTTON, FIRE DISSIPATED. CHANGED APU AND APU FIRE BOTTLE. APU OPS AND LEAK CHECKED GOOD.