N186AZCessna A185F · 1976

On August 31, 2015, at 1852 eastern daylight time, a Cessna A185F, N186AZ, was substantially damaged during landing at Miami Executive Airport (TMB), Miami, Florida. The private pilot and pilot-rated passenger were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight that departed about 1600. The airplane was owned by IZ Air LLC and operated by the private pilot under the provisions of Title 14 Code of Federal Regulations Part 91.The pilot reported that after departure he flew west of the airport, before returning with the intent of practicing an instrument landing system approach. The approach and landing were normal; however, during the rollout, at a speed of about 25 knots, the airplane "turned sharply to the left." The pilot attempted to "correct the turn to the right," but then observed the left main landing gear wheel assembly as it rolled ahead of the airplane, detached from the landing gear. He then noticed a "strong repeating blow" accompanied by a yawing moment, and the left wingtip contacted the ground.

The airplane was examined by a Federal Aviation Administration inspector who reported substantial damage to the left wing and aileron, and buckling of the left side forward fuselage aft of the main landing gear attach point. Two of the four bolts that attached the left wheel axle assembly to the landing gear spring strut were fractured. Portions of the fracture surfaces of both bolts were red/orange in color, similar to rust corrosion.

The landing gear axle assembly, wheel, and bolt remnants were retained and sent to the NTSB Materials Laboratory in Washington D.C., for further examination. Metallurgical examination of the left wheel axle assembly bolts revealed that they exhibited minor iron oxide (corrosion) film on the surface; however, all fracture features were consistent with overstress separation.