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Casualties unknown

Agricultural Aircraft Noses Over After Engine Failure (N45116)

Tule Lake, CA, US

On August 4, 1990, an Air Tractor AT-401 (registration N45116) operated by Macys Flying Service Inc. was involved in an aviation accident near Tule Lake, CA. Investigators recorded the probable cause as: The loss of engine power due to the right magneto distributor gear having approximately 50 percent of its teeth missing. 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 2026-06-22Data APIEditorial standards

The pilot landed in a field after the engine quit during a spray run, colliding with a water line and causing the gear to collapse.

What happened

The aircraft was engaged in an agricultural operation when the engine stopped operating. The pilot initiated a pull-up maneuver to begin another spray pass, but power was lost. Unable to maintain altitude, the pilot executed an emergency landing in an adjacent field. During the touchdown, the aircraft struck a 12-inch water line buried in the ground. The impact caused the landing gear to collapse, and the nose of the aircraft pitched forward over.

The investigation

Following the accident, investigators examined the engine components to determine the cause of the power loss. The inspection revealed significant damage to the ignition system. Specifically, the right magneto was found to be missing approximately 50 percent of the teeth from its distributor gear. This mechanical failure prevented the ignition system from functioning correctly, leading to the sudden stoppage of the engine.

Probable cause

The loss of engine power due to the right magneto distributor gear having approximately 50 percent of its teeth missing.
Engine failure

Frequently asked questions

What happened in the 4 Aug 1990 Air Tractor AT-401 accident near Tule Lake, CA?

The pilot landed in a field after the engine quit during a spray run, colliding with a water line and causing the gear to collapse.

What aircraft was involved and where did it happen?

The accident on 4 Aug 1990 involved an Air Tractor AT-401, registration N45116, operated by Macys Flying Service Inc., at Tule Lake, CA.

What was the probable cause of the accident?

The loss of engine power due to the right magneto distributor gear having approximately 50 percent of its teeth missing.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X24034. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.