Amateur-built PA-18 REPLICA N368G accident near Willow, Alaska

Probable cause

The pilot's exceedance of the airplane’s critical angle of attack while maneuvering for landing, which resulted in an aerodynamic stall and loss of control.

NTSB analysis

The pilot was landing his experimental, amateur-built airplane at a private airport when the airplane impacted terrain in a nose-down, near-vertical attitude short of the runway.

A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. No significant tree impacts were observed on the airframe. Based on the available information, it is likely that the pilot exceeded the airplane’s critical angle of attack while maneuvering for landing, which resulted in an aerodynamic stall and loss of control.

At the pilot’s request, numerous design changes were incorporated into the wings, ailerons, and flaps of the accident airplane. The manufacturer of the kit and the designer of the flaps stated that they told the pilot and builder that the design changes were not recommended; however, the kit was built to the pilot’s specifications. It is likely that the design changes affected the stall characteristic of the airplane; however, the role those changes played in the accident sequence could not be determined.

Text from the NTSB. Open the NTSB docket for ANC22LA004 for the full record.