Casualties unknown

Fatal Water Impact of Experimental RV-4 After Partial Power Loss (N44AZ)

Yellowstonepark, WY, US

On July 4, 1991, a Jerrell RV-4 (registration N44AZ) operated by Donald A. Jerrell was involved in an aviation accident near Yellowstonepark, WY. Investigators recorded the probable cause as: The SCAT tubing from the air intake filter to the fuel injector body was routed in a manner that displaced its internal wire support, causing the tubing walls to collapse and reducing induction airflow to the engine. 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 2026-06-10Data APIEditorial standards

An experimental RV-4 aircraft sustained fatal injuries to the pilot when it impacted a lake during an attempted emergency landing following a partial power loss. Investigation found collapsed SCAT tubing restricting induction airflow.

Accident Occurrence

While operating an experimental RV-4 aircraft, the pilot suffered a partial loss of engine power. The pilot then initiated an emergency landing, aiming for a location near the shoreline of a lake. However, the aircraft struck the water during the landing attempt. The impact resulted in fatal injuries to the pilot.

Investigative Findings

After the accident, a thorough examination of the engine was performed. The inspection revealed that the SCAT tubing connecting the air intake filter to the fuel injector body had an improper routing. This routing caused the internal wire support within the tubing to be displaced. Consequently, the walls of the SCAT tubing collapsed. The collapse significantly reduced the amount of induction air reaching the engine, which was identified as the condition that led to the partial power loss.

Probable cause

The SCAT tubing from the air intake filter to the fuel injector body was routed in a manner that displaced its internal wire support, causing the tubing walls to collapse and reducing induction airflow to the engine.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X17699. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.