Accident Details
On July 2, 2014, at approximately 0842 central daylight time, a Piper PA-28-140, registration N9898W, sustained substantial damage during a forced landing after a loss of engine power during takeoff at Granbury Regional Airport (GDJ), Granbury, Texas. The flight instructor and passenger were not injured. The aircraft was operated by Iron Compass Aviation under 14 Code of Federal Regulations Part 91 as an instructional flight, and visual meteorological conditions prevailed at the time. The aircraft was departing GDJ en route to Waco Regional Airport (ACT), Waco, Texas.
The flight instructor reported that the airplane was about 500 feet above ground level when the engine began to run rough and lost power. The engine rpm decreased to approximately 1,100 rpm as the instructor attempted a 180-degree turn back to the airport. Unable to land on the runway, he performed a forced landing to a field short of the runway. The right wing struck a tree during the landing roll, causing substantial damage.
Examination Findings
On-site examination by Federal Aviation Administration inspectors found no visible damage to the engine and no obvious reason for the power loss. The wreckage was transported to an aircraft storage facility for further examination and an engine run.
An engine run was conducted using an external fuel supply. After priming the fuel system with the electric fuel pump, the engine started but ran roughly, emitting black smoke from the exhaust. After a brief warm-up, the engine would not exceed approximately 1,600 rpm at full throttle. The test was stopped and a compression check performed, revealing no compression in the No. 3 cylinder.
Inspection of the No. 3 cylinder showed the exhaust valve was broken into several pieces, with fragments remaining in the cylinder. The broken valve, spring, exhaust valve keepers, and rotator cap all exhibited carbon buildup. The piston and cylinder head showed gouging and scraping consistent with secondary damage from fragments. The exhaust valve rotator cap had a wear pattern on top matching rocker arm wear and no rotational signatures along the edge where heavy carbon had accumulated.
The engine was a 150-horsepower Lycoming O-320-E2A. The last annual maintenance inspection was performed on June 2, 2014, with a total aircraft time of 3,464 hours. At the time of the accident, the engine had approximately 2,040 hours since its last overhaul, exceeding the recommended time between overhauls (TBO) of 2,000 hours (though not mandatory under Part 91). The aircraft had flown about 46 hours since the last annual/100-hour inspection.
Maintenance History
The engine had accumulated 2,040 hours since overhaul, surpassing the TBO of 2,000 hours. The recommended overhaul interval is advisory under Part 91 operations. The last annual inspection was on June 2, 2014, with no noted discrepancies.