Accident Overview
On September 23, 2024, at approximately 1442 eastern daylight time, a Piper PA-28-161, registration N4298V, was substantially damaged in an accident near LaGrange, Georgia. The aircraft was conducting a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor and student pilot sustained minor injuries.
Events During Flight
The flight instructor reported that after completing maneuvers in the local area, the student pilot performed a touch-and-go landing on runway 31 at LaGrange-Calloway Airport (LGC). During the initial climb after the touch-and-go, at an altitude of about 200 to 300 feet above ground level, the engine began to run rough and the airplane stopped climbing. The instructor took control and turned right for a forced landing on runway 21. During the landing attempt, the engine power did not reduce to idle when the throttle lever was pulled fully aft. The airplane touched down long on the 5,000-foot runway, traveled off the end, and down an embankment, coming to rest upright.
Post-Accident Examination
Examination of the wreckage revealed that the landing gear collapsed and the left wing was substantially damaged. The wreckage was retained for further examination. An Avidyne IFD540 was recovered and forwarded to the National Transportation Safety Board (NTSB) Vehicle Recorders Laboratory for data download. The engine was examined at a recovery facility by a representative of the engine manufacturer under FAA supervision. No issues were identified with the throttle linkage. The examination revealed that the No. 3 cylinder exhaust valve was stuck in the open position; no other anomalies were noted with the airframe or engine. The No. 3 cylinder was then forwarded to the engine manufacturer for metallurgical examination under NTSB supervision.
Engine and Data Analysis
The metallurgical examination revealed rough residues and patches in the valve guide and valve guide material adhered to the exhaust valve stem. Caked residues were observed around the exhaust valve tip. Coked oil deposits appeared present in the rocker box around the exhaust valve guide, and cylinder head cooling fins around the exhaust port appeared white, consistent with heat tinting. Measurements of the exhaust valve guide bore’s inside diameter were all below specification for a new valve guide, and the diametral valve-to-guide clearances were also below specification at the middle and inboard ends. As of publication, the engine manufacturer was conducting an internal investigation to address the issue. Download of the Avidyne IFD540 data revealed no engine data had been stored. Review of maintenance records showed the No. 3 cylinder had operated about 1,072 hours since its installation new on December 22, 2021.