As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING APU START A LOUD BANG WAS NOTED. SHORTLY AFTER THE APU SHUTDOWN SMOKE WAS NOTED COMING FROM THE INTAKE OF THE, AUXILIARY POWER UNIT. THE APU HAD CATASTROPHIC FAILURE TO THE HOT SECTION. TURBINE ASSY HAD DISINTEGRATED. SUBSTANTIAL TWISTING DAMAGE TO THE APU STRUCTURAL CASE WAS NOTED. REPAIR TEAR DOWN REPORTS HAVE BEEN REQUESTED, AFH 26440.23, AFC 21722.