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Casualties unknown

Engine Cylinder Head Fracture Leads to Forced Landing and Nose-Over (N7220)

Nyssa, OR, US

On July 23, 2004, a Grumman G-164A (registration N7220) operated by Donald L. Taylor was involved in an aviation accident near Nyssa, OR. Investigators recorded the probable cause as: The number four cylinder head fractured near where the cylinder head was screwed into the cylinder barrel, and the fracture was of such a nature that it kept the cylinder from developing the compression necessary for detonation of the fuel/air mixture. 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 2026-07-04Data APIEditorial standards

During an aerial application flight, a loud bang preceded engine power loss, forcing a landing in a field where the main gear collapsed in soft terrain, resulting in a nose-over. Investigation found a fractured number four cylinder head.

Incident Overview

An aerial application aircraft experienced a sudden loss of engine power during a spraying run. The pilot reported hearing a loud bang, after which the engine significantly reduced power output. Unable to maintain altitude, the pilot initiated a forced landing in a nearby agricultural field.

Landing and Subsequent Events

The initial touchdown was uneventful; however, the main landing gear contacted soft terrain and dug in. The gear subsequently collapsed, causing the aircraft to nose over.

Investigation Findings

Following the incident, examination determined that the number four cylinder head had fractured in flight. The fracture occurred near the point where the cylinder head is screwed into the cylinder barrel. The nature of the fracture prevented the cylinder from achieving the compression necessary for detonation of the fuel/air mixture, leading to the power loss.

Probable cause

The number four cylinder head fractured near where the cylinder head was screwed into the cylinder barrel, and the fracture was of such a nature that it kept the cylinder from developing the compression necessary for detonation of the fuel/air mixture.
Engine failure

Frequently asked questions

What happened in the 23 Jul 2004 Grumman G-164A accident near Nyssa, OR?

During an aerial application flight, a loud bang preceded engine power loss, forcing a landing in a field where the main gear collapsed in soft terrain, resulting in a nose-over. Investigation found a fractured number four cylinder head.

What aircraft was involved and where did it happen?

The accident on 23 Jul 2004 involved a Grumman G-164A, registration N7220, operated by Donald L. Taylor, at Nyssa, OR.

What was the probable cause of the accident?

The number four cylinder head fractured near where the cylinder head was screwed into the cylinder barrel, and the fracture was of such a nature that it kept the cylinder from developing the compression necessary for detonation of the fuel/air mixture.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20040803X01132. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.