Amateur-built TEAM ACFT Z-MAX accident near Rigby, Idaho, August 9, 2023

The NTSB's narrative final · quoted from the NTSB record

Before takeoff for a local flight, the pilot emptied the wing tanks, cleaned the carburetors and fuel pump, and test ran the engine. The airplane had not flown in 8 years. A witness saw the airplane taxi up and down the taxiway multiple times both the day before and day of the accident, and then saw it depart on the accident flight. The witness heard the engine sputtering shortly after takeoff and stated that it was not operating at full power. The witness recalled the airplane made an abrupt left turn above the airport, and while in the turn, the left wing dropped sharply. The airplane then descended and impacted the ground with the left wing. Postaccident examination of the wreckage revealed that two wires from the starter solenoid to the voltage regulator were inadequately secured and worn on their outer sheath, revealing the internal copper wires. The wires were routed across the right forward side of the engine support structure. The copper wires were in contact with the support structure, which likely grounded the airplane’s electrical system and caused the engine to lose power. The sudden drop of the left wing during the turn was consistent with the pilot exceeding the airplane’s critical angle of attack during the turn, resulting in an aerodynamic stall at an altitude too low for recovery.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.