On June 16, 2007, a Piper PA-12 (registration N2343M) was involved in an aviation accident near Imnaha, OR. Investigators recorded the probable cause as: The pilot's failure to adjust tire pressure for the dirt strip surface conditions, which resulted in the left tire striking a rock and the airplane veering off the runway. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Aircraft veered off runway after tire struck rock during landing rollout at backcountry dirt strip; pilot had not adjusted tire pressure for surface conditions.
What happened
The pilot attempted to land the aircraft at a remote dirt airstrip situated alongside a river bank. During the landing roll, the left tire struck a rock, causing the airplane to veer off the runway to the left. The tires had been inflated to 25 pounds per square inch (psi) before the flight. On previous flights to the dirt strip, the pilot had deflated the tire pressure to 12-15 psi and landed without incident.
Findings
The airplane sustained substantial damage, including a bent wing strut. The discrepancy in tire pressure compared to previous successful landings on the same surface likely contributed to the loss of directional control after the tire impact.
Probable cause
The pilot's failure to adjust tire pressure for the dirt strip surface conditions, which resulted in the left tire striking a rock and the airplane veering off the runway.