NTSB Identification: LAX02LA147.
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Accident occurred Wednesday, May 01, 2002 in Kingman, AZ
Probable Cause Approval Date: 04/25/2006
Aircraft: Air Tractor AT-802A, registration: N90802
Injuries: 1 Uninjured.

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

The airplane ground looped during landing and the left main landing gear strut fractured and separated. The pilot told a Federal Aviation Administration (FAA) inspector that the landing gear strut collapsed unexpectedly, and without warning, during the landing roll, and the airplane ground looped to the right. It was not subjected to an abnormal load during landing and the airplane was relatively light with no chemical load aboard and about 1,300 pounds of fuel. The inspector examined the airplane and said the left landing gear leaf broke inside the saddle. There was rust and beach marks in the fracture face indicative of a pre-existing crack. The FAA inspector said the left landing gear strut, a single spring steel leaf, separated in the shoulder area where the strut enters the saddle at the fuselage skin line. The left landing gear wheel was broken in the outboard flange area and the tire was deflated. The tire exhibited deep radial scratch marks on the outboard side wall. The aileron hinge bracket at the left wing tip was bent inboard and striations on the left wing lower surface were oriented spanwise. The left wing outer half-span was bent upward accompanied by compression wrinkling of the upper wing skin. Examination of the fracture by a metallurgical laboratory revealed that the strut met the manufacturer's chemical, hardness, and materials specifications for the component. The fracture through the strut was characterized by two distinct modes. The first was 0.08 inches in depth and 0.37 inches in width and exhibited features consistent with fatigue. The fatigue crack had multiple initiation sites along the top surface in an area that had fretting damage. The remainder of the fracture face displayed gross overload features. According to the laboratory report, the transverse failure of the strut resulted from an overload condition, with high side and drag loads, well in excess of the design ultimate load for the component.

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

The failure of the pilot to maintain directional control during landing.

Full narrative available

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