Wsk Pzl Mielec M-18A N81705 accident near Mountain Home, Idaho

Probable cause

The pilot's inadequate preflight inspection, and, his failure to properly secure the aircraft as he left the cockpit with the engine operating, which resulted in the unoccupied airplane inadvertently becoming airborne and colliding with a fence and terrain.

NTSB analysis

The pilot reported he was taxing the airplane to the active runway when he realized the airplane's tail wheel lock was engaged. With the engine still running, the pilot set the parking brake, installed the control lock and exited the airplane with the intention of manually unlocking the tail wheel. When the pilot exited the cockpit he inadvertently knocked/pushed the throttle forward, to a high power setting, and the airplane started to roll across the taxiway. The unoccupied airplane accelerated, momentarily became airborne, and collided with an airport perimeter fence and terrain. The airplane sustained substantial damage to the fuselage, empennage and both wings. No pre accident mechanical malfunctions or failures were reported.

Text from the NTSB. Open the NTSB docket for WPR09CA041 for the full record.