N36025

On June 1, 1994, at 0640 Pacific daylight time, a Piper PA-28R- 201T, N36025, collided with ground obstructions while attempting a forced landing at the Trinity Center, California, airport. The forced landing was precipitated by a total loss of engine power while in cruise flight. The aircraft was operated by Rainbow Air of Long Beach, California, and was rented by the pilot for a personal cross-country flight. Visual meteorological conditions prevailed at the time and an IFR flight plan was filed for the operation. The aircraft incurred substantial damage. The certificated private pilot incurred minor injuries and the passenger was not injured. The flight originated at the Medford, Oregon, airport on the morning of the accident at 0550 as an IFR cross-country flight to Long Beach, California.

The pilot said in his statement that while en route at 11,000 feet, he heard a "grinding noise" in the engine followed by a propeller overspeed. A few seconds later, the engine suddenly lost all power. The pilot said he informed Oakland ARTCC (ZOA) of his problem within 30 seconds of the event and they provided vector to nearest airport, which was Trinity Center. The pilot said he set up for a dead stick approach to the airport; however, he was unable to make the runway. The aircraft touched down gear-up in a ditch, bounced out and onto the parking lot, then crashed into a parked aircraft.

The engine was removed from the airframe for a detailed examination, which was conducted on June 9, 1994, at Hillside Aviation in Redding, California. The examination was conducted by a Federal Aviation Administration (FAA) airworthiness inspector from the Sacramento, California, Flight Standards District Office, with assistance provided by a technical representative from Teledyne Continental Motors. The reports from both the FAA inspector and the Teledyne Continental Motors representative are attached as an exhibit to this report.

Disassembly of the engine revealed fretting on the parting surfaces of the number 1 main bearing saddle. The crankshaft was found fractured across the number 1 crankpin at the interface with the number 2 long cheek.

The number 1 connecting rod remained on the number 1 crankpin. One rod end cap nut was found without a cotter pin installed in the castlenated nut. The second rod end cap nut was found with a shorter than normal cotter pin installed. The number 1 connecting rod bearing was found partially swaged out of the rod big end, with fretting observed on the bearing surfaces. The side faces of connecting rod number 1 were scored.

The fractured crankshaft was sent to the FAA Manufacturing Satellite Inspection Office in Mobile, Alabama, for analysis by the Teledyne Continental materials laboratory under FAA supervision. The metallurgical analysis report completed by Teledyne Continental is attached as an exhibit to this report. In pertinent part, the materials laboratory found that the crankshaft fractured at the number 1 crankpin due to a sub- surface initiated fatigue crack.

The engine maintenance records were examined in detail. The Continental TSIO-360-FB1 engine, serial No. 281066-R was remanufactured by the Continental factory on June 24, 1991, and installed in the accident aircraft on July 4, 1991. At the time of the accident, the engine had accrued 1,015 operating hours since remanufacture. Engine cylinders number 1 and 4 were replaced on May 9, 1994, 29 hours prior to the accident.