What was found
AFTER DEPARTURE, AT ABOUT 1000 FEET AGL, THE PILOT REPORTED THAT THE LT ENGINE MANIFOLD PRESSURE DROPPED SUDDENLY, THE ENGINE SURGED AND THEN QUIT RUNNING. THE PILOT RETURNED TO DEPARTURE SAFELY. UPON EXAMINATION, IT WAS FOUND THAT THE EXHAUST FLANGE AT THE WASTE GATE HAD CRACKED AND BROKEN OFF. THE RESULTING BLAST OF HEAT FROM THE EXHAUST MELTED PART OF THE WASTE GATE CONTROLLER, SPILLING OIL AND CAUSING AN INFLIGHT FIRE. THE DAMAGE FROM THE FIRE WARPED THE SKINS ON THE BOTTOM OF THE WING, BURNED THE OUTER SKIN OFF THE LT MLG DOOR AND BURNED LARGE HOLES IN THE FLAP. IT IS HIGHLY RECOMMENDED TO PAY CLOSE ATTENTION TO THE FLANGES AND WELDS ON THESE PMA ASSEMBLIES, AS FAILURE OF THE EXHAUST PIPES COULD CAUSE CONSIDERABLE DAMAGE AS IT DID IN THIS CASE, AND COULD LEAD TO LOSS OF THE AIRCRAFT AND LIFE. IT MUST BE NOTED THAT THE MFG WELD PROCESS IN THIS AREA HAS RECENTLY CHANGED. (K)