What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot reported left side engine cylinders seperated on a maintenance test flight for engine vibrations. Ditched. (.4)the pilot was conducting a maintenance test flight in the traffic pattern when the engine lost power and he made a forced landing. Two days before the accident test flight, a company pilot made an unscheduled landing due to a rough running engine with a vibration. A review of the aircraft inspection discrepancy logs and maintenance records revealed that maintenance personnel removed and cleaned the fuel injector nozzles, the servo unit screen was flushed, and a compression check was completed. Four engine ground runs were conducted with a rough running engine and vibrations noted in the first three runs. The fourth ground run did not note any anomalies. Review of the records found two operator's inspection discrepancy records for this aircraft. Examination of the documents disclosed that they are essentially the same, except for item number 3. On the first document the item 3 discrepancy stated that the no. 5 cylinder fuel injector nozzle needed replacement, with a further note that none were in stock. On the second docume nt item 3 said that the fuel injector nozzles were cleaned and reinstalled, and that a ground run-up was normal. The company dispatcher instructed the pilot to perform the test flight as the airplane scheduled to return to service the same day. The pilot performed the ground checklist, which included checking the magnetos and propeller. He did not note any discrepancies. After takeoff no engine performance malfunctions were noted; however, while on base leg, the aircraft engine banged three times and then parts flew through the engine colwing. The colwing separated and struck the empennage. The pilot subsequently ditched the aircraft in the ocean, where it sank and was not recovered. (-23)the aircrft sustained a catastrophic engine failure while performing a maintenance test flight. The aircraft was lost in water approxiamtely 200' deep and was not recovered. This investigation concluded that the cause of the accident was catastropic engine failure of unknown origin.
As the FAA filed it
PILOT REPORTED LEFT SIDE ENGINE CYLINDERS SEPERATED ON A MAINTENANCE TEST FLIGHT FOR ENGINE VIBRATIONS. DITCHED. (.4)THE PILOT WAS CONDUCTING A MAINTENANCE TEST FLIGHT IN THE TRAFFIC PATTERN WHEN THE ENGINE LOST POWER AND HE MADE A FORCED LANDING. TWO DAYS BEFORE THE ACCIDENT TEST FLIGHT, A COMPANY PILOT MADE AN UNSCHEDULED LANDING DUE TO A ROUGH RUNNING ENGINE WITH A VIBRATION. A REVIEW OF THE AIRCRAFT INSPECTION DISCREPANCY LOGS AND MAINTENANCE RECORDS REVEALED THAT MAINTENANCE PERSONNEL REMOVED AND CLEANED THE FUEL INJECTOR NOZZLES, THE SERVO UNIT SCREEN WAS FLUSHED, AND A COMPRESSION CHECK WAS COMPLETED. FOUR ENGINE GROUND RUNS WERE CONDUCTED WITH A ROUGH RUNNING ENGINE AND VIBRATIONS NOTED IN THE FIRST THREE RUNS. THE FOURTH GROUND RUN DID NOT NOTE ANY ANOMALIES. REVIEW OF THE RECORDS FOUND TWO OPERATOR'S INSPECTION DISCREPANCY RECORDS FOR THIS AIRCRAFT. EXAMINATION OF THE DOCUMENTS DISCLOSED THAT THEY ARE ESSENTIALLY THE SAME, EXCEPT FOR ITEM NUMBER 3. ON THE FIRST DOCUMENT THE ITEM 3 DISCREPANCY STATED THAT THE NO. 5 CYLINDER FUEL INJECTOR NOZZLE NEEDED REPLACEMENT, WITH A FURTHER NOTE THAT NONE WERE IN STOCK. ON THE SECOND DOCUME NT ITEM 3 SAID THAT THE FUEL INJECTOR NOZZLES WERE CLEANED AND REINSTALLED, AND THAT A GROUND RUN-UP WAS NORMAL. THE COMPANY DISPATCHER INSTRUCTED THE PILOT TO PERFORM THE TEST FLIGHT AS THE AIRPLANE SCHEDULED TO RETURN TO SERVICE THE SAME DAY. THE PILOT PERFORMED THE GROUND CHECKLIST, WHICH INCLUDED CHECKING THE MAGNETOS AND PROPELLER. HE DID NOT NOTE ANY DISCREPANCIES. AFTER TAKEOFF NO ENGINE PERFORMANCE MALFUNCTIONS WERE NOTED; HOWEVER, WHILE ON BASE LEG, THE AIRCRAFT ENGINE BANGED THREE TIMES AND THEN PARTS FLEW THROUGH THE ENGINE COLWING. THE COLWING SEPARATED AND STRUCK THE EMPENNAGE. THE PILOT SUBSEQUENTLY DITCHED THE AIRCRAFT IN THE OCEAN, WHERE IT SANK AND WAS NOT RECOVERED. (-23)THE AIRCRFT SUSTAINED A CATASTROPHIC ENGINE FAILURE WHILE PERFORMING A MAINTENANCE TEST FLIGHT. THE AIRCRAFT WAS LOST IN WATER APPROXIAMTELY 200' DEEP AND WAS NOT RECOVERED. THIS INVESTIGATION CONCLUDED THAT THE CAUSE OF THE ACCIDENT WAS CATASTROPIC ENGINE FAILURE OF UNKNOWN ORIGIN.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.
Other reports on N1256H · 1
Matched to the same aircraft by N-number and date.