Aircraft: Cessna 150. Injuries: None. Location: Juneau, Alaska. Aircraft damage: Substantial.
What reportedly happened: The flight instructor was demonstrating a short field, three-point landing. The touchdown was normal, but during the landing roll a gust of wind pushed the airplane, and it began to turn to the right. When the instructor applied left brake in an attempt to correct for the right turn, the left main landing gear broke.
As the broken gear leg dug into the runway, the airplane pivoted 180° to the left, and the left wing hit the runway.
The airplane sustained substantial damage to the left wing and fuselage.
The flight instructor stated that during the last annual inspection, about four months before the accident, he noticed corrosion on the main landing gear legs and ground it off using a hand-held grinder.
The service manual specified to carefully remove any rust by light sanding and the sanding must blend the damage into the adjacent area in an approximate 20:1 ratio.
Examination of the landing gear revealed evidence of the improper maintenance and corrosion damage, which weakened the gear and led to fatigue cracking and an overstress fracture.
Probable cause: The collapse of the left main landing gear during the landing roll, as a result of fatigue cracking. Contributing to the accident was the improper maintenance of the landing gear.
NTSB Identification: ANC13LA016
This December 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
