Grumman Acft Eng Cor-Schweizer G-164B N6726Q accident near Courtland, California

Probable cause

The pilot's failure to maintain clearance from terrain during low-altitude maneuvers.

NTSB analysis

The pilot reported that during an aerial application flight he was established and stable on an east-to-west spray pass. He recalls checking the pump pressure gauge for an indication of an empty load when he felt and heard a “significant slam” and felt a grinding sensation. The airplane had impacted level terrain and came to rest upside down. The airplane sustained substantial damage to both wings and the tail assembly. The pilot reported that there were no known mechanical malfunctions or failures with the aircraft prior to the accident.

Text from the NTSB. Open the NTSB docket for WPR10CA289 for the full record.