NTSB Identification: ANC12TA035
14 CFR Public Use
Accident occurred Friday, April 27, 2012 in Paxon, AK
Probable Cause Approval Date: 02/27/2013
Aircraft: PIPER PA-18-150, registration: N7059
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this public aircraft accident report.

The pilot said he was landing a ski-equipped airplane on a remote, frozen and snow-covered lake. He said that as the skis contacted the flat and smooth snow-covered ice, the airplane pitched forward violently, then to the right, and then back to the left. A postaccident examination revealed that the right main landing gear had collapsed and subsequently folded under the airplane. An examination of the right main landing gear revealed a fractured suspension strut that had fractured laterally across a bored and threaded area of the suspension tube. The fractured tube was examined under magnification and there was no evidence of external corrosion. The tube had a long radius bend adjacent to the internal threads. The fracture had a clean, evenly colored fracture surface, and no evidence of repeated fracturing (beach marking). The fracture appearance is consistent with an overstress fracture. The pilot noted that, other than the fractured main landing suspension strut, there were no preaccident mechanical anomalies with the airplane.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A separation of the right main landing gear suspension strut assembly due to overstress, which resulted in the collapse of the main landing gear while landing.

Full narrative available

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