ERA12LA293 · Prendergast John/Vans RV-7A
Prendergast John/Vans RV-7A · Accident: loss of engine power (total) while maneuvering
From Eastern WV Regional Airport/Shepherd Field (MRB) to Eastern WV Regional Airport/Shepherd Field (MRB)
Event
- NTSB case
- ERA12LA293
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Prendergast John/Vans RV-7A
- Aircraft type
- Prendergast John/vans RV-7
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N5025G
- Operator
- John Prendergast
- Onboard fatalities
- Unknown
- Route
- From Eastern WV Regional Airport/Shepherd Field (MRB), Martinsburg, WVTo Eastern WV Regional Airport/Shepherd Field (MRB), Martinsburg, WV
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (total)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
According to the pilot, after about 2 1/2 hours of local flight, while maneuvering at 3,000 feet, the airplane's rotary engine coolant temperature rose. As the pilot turned the airplane back toward the departure airport, the engine seized and would not turn over during an attempted restart. The pilot performed a forced landing in a field, and the airplane nosed over. The pilot, who was also the airplane's builder, subsequently disassembled the engine and found that the stationary gear/bearing was frozen to the eccentric shaft. The pilot also reported that he had recently attempted to fine tune the engine by having the side and intermediate housings undergo lap grinding. The pilot knew the grinding would require wider spacers, which he used, but which may have still been insufficient in width. The insufficient width resulted in bearing oil hole misalignment on the eccentric shaft, which blocked oil from reaching the rotating engine and reduction drive shaft parts.
Probable cause
The pilot/builder's misjudgment of the required spacer width needed after engine housing lap grinding, which resulted in bearing oil hole misalignment and insufficient internal engine lubrication.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA12LA293
- Event ID
- 20120420X35114
- Case number
- ERA12LA293
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: a7019c5af897dc6293d76d8950d39a33c1ccf23978b203dd2f49e6f5506ca847; retrieved 2026-09-15T17:50:28.714Z.