Prendergast John/Vans RV-7A N5025G

Summary

On 16 April 2012 at about 19:00 local time, a Prendergast John/Vans RV-7A registered N5025G, operated by John Prendergast, was involved in an accident near Gerrardstown, West Virginia, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

16 April 2012 at 19:00

Classification

Accident

Location

Gerrardstown, West Virginia, United States

Coordinates

39.3517, -78.0997

Aircraft

Prendergast John/Vans RV-7A

Registration

N5025G

Category

Airplane

Engines

1

Operator

John Prendergast

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Martinsburg → Martinsburg

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

ERA12LA293

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.