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Grumman G-164A Accident Involving Ground Impact and Fire (N7926)

Rosalia, WA, US

On May 6, 1997, a Grumman G-164A (registration N7926) operated by Joseph F. Dion was involved in an aviation accident near Rosalia, WA. Investigators recorded the probable cause as: The pilot-in-command's failure to maintain clearance with terrain. Factors contributing to the accident were, hilly terrain conditions and impairment due to recent use of marihuana. 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

A Grumman G-164A spray plane impacted hilly terrain with its tail wheel and main gear, nosed over on a paved road, and burned. Toxicological tests detected recent marijuana use in the pilot.

Accident Narrative

The pilot-in-command departed the airport in a Grumman G-164A spray plane. While en route to the destination field and overflying hilly terrain, the aircraft's tail wheel impacted the ground, followed by the main gear. The aircraft continued over an embankment, nosing over while crossing a paved road, before coming to rest and burning.

Aircraft and Load

The aircraft was a Grumman G-164A. There was no evidence that the pilot jettisoned the 2,040-pound herbicide load. Propeller slash marks early in the ground track indicated high engine RPM at the initial ground impact.

Toxicological Analysis

Toxicological evaluation of samples from the pilot-in-command revealed 0.002 ug/ml of Tetrahydrocannabinol detected in blood, 0.08 ug/ml of Tetrahydrocannabinol Carboxylic Acid detected in blood, and 0.035 ug/ml of Tetrahydrocannabinol Carboxylic Acid detected in urine. These levels indicate fairly recent (within several hours) use of Marihuana.

Frequently asked questions

What happened in the 6 May 1997 Grumman G-164A accident near Rosalia, WA?

A Grumman G-164A spray plane impacted hilly terrain with its tail wheel and main gear, nosed over on a paved road, and burned. Toxicological tests detected recent marijuana use in the pilot.

What aircraft was involved and where did it happen?

The accident on 6 May 1997 involved a Grumman G-164A, registration N7926, operated by Joseph F. Dion, at Rosalia, WA.

What was the probable cause of the accident?

The pilot-in-command's failure to maintain clearance with terrain. Factors contributing to the accident were, hilly terrain conditions and impairment due to recent use of marihuana.

More accident analyses

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001208X08016. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.