SEA96LA190

The pilot reported that as the airplane touched down on the turf runway, the right main landing gear collapsed. The airplane then veered to the right and nosed over. A postaccident examination revealed that the right main landing gear had separated at the axle. A metallurgical examination of the break revealed that the fracture was due to overload that started on the bottom of the tube and progressed upwards. The specialist conducting the test stated that the fracture progression was consistent with a large upward load on the end of the axle such as would be experienced with a hard landing. However, the time of the overload was not determined.

On August 13, 1996, at 1150 mountain daylight time, an Aviat Inc. A-1, N56LG, registered to Scott Erickson Aviation and operated by the pilot as a 14 CFR Part 91 personal flight, nosed over during the landing roll on a dirt airstrip near Worland, Wyoming. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the commercial pilot and his passenger were not injured. The flight had departed from Fairburn, South Dakota, approximately two hours prior to the accident.

The pilot reported in a written statement, that he landed the airplane into the wind. As the airplane touched down, the right main landing gear collapsed. The airplane veered to the right and nosed over. After the accident, the right main landing gear tire was found approximately 100 feet from the airplane, to the left of the runway.

A metallurgical inspection of the right side wheel axle was performed by AADFW, Inc. Euless, Texas. The results of the tests revealed that the chemical and physical properties of the tube were acceptable and no defects in the material quality were noted. The specialist performing the test reported that "the fracture was an overload fracture that started on the bottom of the tube and progressed upwards. This fracture progression is consistent with a large upward load on the end of the axle such as would be experienced in a hard landing." The fracture passed through a toe weld, however, the specialist determined that the weld had nothing to do with the initiation of the fracture. The timing of the overload failure was not determined.