Casualties unknown

Fatigue Failure of Exhaust Valve Leads to Forced Landing (N3064Z)

Bagdad, AZ, US

On February 11, 1991, a Piper PA22-160 (registration N3064Z) operated by Robert L. Boyd was involved in an aviation accident near Bagdad, AZ. Investigators recorded the probable cause as: The fatigue failure of a sodium-filled exhaust valve, which caused the engine to run rough and lose power, leading to a forced landing where the pilot misjudged altitude and two rear passengers were ejected through the door on touchdown after releasing their… 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

A pilot executed a forced landing in the desert after an engine lost power due to a fatigue failure of a sodium-filled exhaust valve.

What happened

The aircraft was operating at normal cruise altitude when the engine began to run roughly and lose power. The pilot declared an emergency and executed a forced landing in a sparsely populated desert area. During the landing flare, the pilot misjudged the altitude and landed hard. The two rear passengers, believing there was a fire onboard, released their seat belts before touchdown and were ejected through the door upon impact.

The investigation

Examination of the engine disclosed that the sodium-filled exhaust valve had failed in fatigue.

Findings

The pilot misjudged altitude during the landing flare. Fuel exhaustion was not cited; rather, the mechanical failure was the primary cause. The two rear passengers were ejected through the door on touchdown after releasing their seat belts prematurely due to a perceived fire hazard.

Probable cause

The fatigue failure of a sodium-filled exhaust valve, which caused the engine to run rough and lose power, leading to a forced landing where the pilot misjudged altitude and two rear passengers were ejected through the door on touchdown after releasing their seat belts prematurely due to a perceived fire hazard.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X16470. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.