No fatalities

11 Dec 2012: PIPER PA-18-150 — Okaton, SD

Okaton, SD, United States

On 11 Dec 2012, a PIPER PA-18-150 was involved in an aviation accident near Okaton, SD. No fatalities were reported. Investigators recorded the probable cause as: The pilot's failure to perform an adequate preflight inspection of the airplane and obstruction of the aileron control system by snow and ice, which led to a loss of control during flight. This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

A pilot reported that snow which had accumulated on the wings two days prior may have melted and refrozen at the aileron gaps. After a cursory snow removal and incomplete preflight, the airplane entered an uncontrolled left turn and descended into trees.

Incident Overview

A pilot reported that two days before the accident, snow had accumulated on the wings of the airplane while it was parked in an open-front hangar. The following day, temperatures rose, and the pilot believed the snow melted and ran rearward to the aileron gap and hinge locations, where it refroze overnight.

On the day of the accident, the pilot was in a hurry to use the airplane to check his pastures. He brushed the snow off the wings but did not perform a thorough preflight inspection. Specifically, he did not check the freedom of movement of the ailerons.

Sequence of Events

After takeoff, the airplane began turning to the left. The pilot attempted to correct the turn but reported no response from the controls. Looking out at the wings, he observed that the ailerons were not responding to control inputs as they should. During his attempts to regain control, the airplane descended into trees.

Postaccident Examination

A postaccident examination of the airplane revealed no defects that were determined to have existed prior to the accident. The airplane sustained substantial damage to both wings, the fuselage, and the tail surfaces.

Contributing factors

PilotInadequate inspectionContributed to outcome