As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PUSHBACK FROM THE GATE, CREW REPORTED THE APU GENERATOR DROPPED OFF LINE. GORUND CREW ALERTED PILOT THAT THERE WAS AN APU TAILPIPE FIRE. NO APU FIRE DETECTION WAS NOTED BUT CREW ARMED AND DISCHARGED THE APU FIRE BOTTLE. THE MSY FIRE DEPARTMENT WAS CALLED AS A PRECAUTION. FLIGHT RETURNED TO THE GATE. (M)