What was found
EVIDENCE OF FLAME & SMOKE COMING FROM APU TAILPIPE. SUSPECT APU TURBINE SEALS BLOWN & WILL REQUIRE APU REPLACEMENT. IAW DF151, APU FIRE SYS DEACTIVATED. DO NOT OPERATE APU UNTIL FIRE SYS RESTORED. APU SMOKE, FLT CREW ELECTED TO DISCHARGE APU FIRE BOTTLE PRECAUTIONARY. NO EVIDENCE OF DAMAGE TO APU COMPARTMENT NOTED. CHECKED APU EXHAUST AREA & APU COMPARTMENT, NO DEFECTS & OR HEAT DAMAGE NOTED. APU NOT TO BE OPERATED UNTIL FIRE EXTINGUISHING SYS IS REPAIRED & MADE SERVICEABLE. REPLACED APU FIRE BOTTLE & DISCHARGE IAW MM.