Casualties unknown

2007-06-29: Evenson Roger J VANS RV-9A (N394RS) — Tucson, AZ

Tucson, AZ, US

On June 29, 2007, an Evenson Roger J VANS RV-9A (registration N394RS) was involved in an aviation accident near Tucson, AZ. Investigators recorded the probable cause as: The pilot's adjustment of the waste gate valve allowed it to go over center and stick, causing failure of the servo motor, which prevented the waste gate valve from opening. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

During the initial climb, the pilot noted high manifold pressure and engaged the supercharger override, but power still dropped. The pilot attempted an emergency landing; the main gear hit brush and soft dirt, the nose gear dug in, and the airplane nosed over.

Takeoff and Power Loss

During the takeoff initial climb, the pilot observed a high manifold pressure reading and engaged the supercharger pressure override, but the manifold pressure remained unchanged. Subsequently, the engine began to lose power, and the airplane could no longer sustain a climb.

Emergency Landing

The pilot attempted an emergency landing. During the landing sequence, the main landing gear contacted brush and soft dirt, causing the nose gear to dig into the ground. The airplane then nosed over and came to rest inverted.

Aircraft Engine

The airplane was equipped with an Eggenfellner EJ-25 engine, a water-cooled, four-cylinder, supercharged Subaru automobile engine converted for aircraft use.

Post-Accident Examination

Examination of the engine after the accident revealed that a failed waste gate servo motor had prevented the waste gate valve from opening. Prior to the accident, the pilot had adjusted the waste gate valve such that it was allowed to go over center and stick, which caused the failure of the servo motor.

Probable cause

The pilot's adjustment of the waste gate valve allowed it to go over center and stick, causing failure of the servo motor, which prevented the waste gate valve from opening.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20070711X00904. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.