Casualties unknown

1994-05-08: Schweizer G-164B (N3629E) — Williams AG Service, Inc. — Gridley, CA

Gridley, CA, US

On May 8, 1994, a Schweizer G-164B (registration N3629E) operated by Williams AG Service, Inc. was involved in an aviation accident near Gridley, CA. Investigators recorded the probable cause as: A crack in the number 8 cylinder head that extended between the spark plug holes, which caused the engine to fail during flight. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.

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

A pilot conducting aerial seeding operations experienced an unexpected engine failure over a farm field. The attempt to divert to a nearby landing area resulted in the aircraft colliding with a canal ditch.

What happened

The operator of the aircraft reported that the pilot was engaged in agricultural work, specifically spraying seeds across a farm field. During this operation, the engine experienced a sudden failure. In response to the loss of power, the pilot attempted to maneuver the aircraft toward a nearby field for an emergency landing. However, the aircraft collided with a canal ditch before a successful landing could be achieved.

The investigation

Following the accident, a postaccident examination of the engine was conducted to determine the mechanical cause of the failure. The inspection revealed significant damage to the internal components. Specifically, investigators found a crack in the number 8 cylinder head. This fracture extended from one spark plug hole directly to the other spark plug hole, indicating a structural failure within that specific cylinder.

Findings

The investigation identified the mechanical defect as the primary factor in the loss of engine power. The crack in the number 8 cylinder head compromised the integrity of the combustion chamber, leading to the cessation of engine operation while the aircraft was airborne over agricultural land.

Probable cause

A crack in the number 8 cylinder head that extended between the spark plug holes, which caused the engine to fail during flight.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001206X01320. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.