CircumFlightN6269H accident
NTSB CEN21LA359 · 2021-08-06 · Gosport, IN
Docket — crew, injuries and powerplant
Summary
The pilot stated that, during cruise flight, the airplane experienced “significant” vibration, which was followed by a total loss of engine power. The pilot performed a forced landing to a field, during which the airplane nosed over and impacted terrain. Postaccident examination of the airplane engine revealed that the No. 4 cylinder exhaust valve stem was broken at its base and the seat was turned sideways. Pieces of the stem were found in the cylinder. The failure of the exhaust valve resulted in reduced engine compression leading to the total loss of engine power.
Full narrative
On August 5, 2021, about 2030 eastern daylight time, a Piper J3C-65, N6269H, was substantially damaged when it was involved in an accident near Gosport, Indiana. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot stated that, during cruise flight, the airplane experienced “significant” vibration, which was followed by a total loss of engine power. The pilot performed a forced landing to a field that caused the airplane to nose over and impact terrain, resulting in substantial damage to the rudder and cowling.
Postaccident examination of the airplane engine revealed that the No. 4 cylinder exhaust valve stem was broken at its base. The valve seat was turned sideways, and pieces of broken metal were found in the cylinder. The cylinder’s rockers and springs did not exhibit any failure.
Probable cause
A total loss of engine power during cruise flight due to the failure of a cylinder exhaust valve stem, which led to a forced landing during which the airplane impacted terrain. The National Transportation Safety Board determined the probable cause of this accident.
Circumstances
- Event type
- Accident
- Highest injury
- None
- Weather conditions
- Visual Meteorological Cond
- Light condition
- Day
- Sky condition
- NONE
- Ceiling (ft)
- 0
- Visibility (sm)
- 10
- Wind direction
- 0
- Temperature (F)
- 77
- Distance from field
- 0.0
Aircraft
| Registration | Make | Model | Damage | FAR part |
|---|---|---|---|---|
| N6269H | — | — | SUBS | 091 |
Sequence of events
| # | Occurrence | Phase |
|---|---|---|
| 1 | Enroute Loss of engine power (total) | Climb |
| 2 | Landing Off-field or emergency landing | Cruise |
| 3 | Landing Collision during takeoff/land | Cruise |
| 4 | Enroute Powerplant sys/comp malf/fail defining | Climb |
Findings
| Finding | |
|---|---|
| Aircraft-Aircraft power plant-Engine (reciprocating)-(general)-Failure | cause |