Event Summary
On August 31, 2015, at 1852 eastern daylight time, a Cessna A185F, registration N186AZ, was substantially damaged during landing at Miami Executive Airport (TMB) in Miami, Florida. The private pilot and a pilot-rated passenger were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight, which had departed about 1600. The airplane was owned by IZ Air LLC and operated by the private pilot under Title 14 Code of Federal Regulations Part 91.
According to the pilot, after departure he flew west of the airport before returning to practice 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 rolling 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.
Examination Findings
An examination by a Federal Aviation Administration inspector revealed substantial damage to the left wing and aileron, as well as 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 exhibited a red/orange coloration, similar to rust corrosion.
Metallurgical Analysis
The landing gear axle assembly, wheel, and bolt remnants were sent to the NTSB Materials Laboratory in Washington, D.C., for further examination. Metallurgical examination of the left wheel axle assembly bolts showed a minor iron oxide (corrosion) film on the surface. However, all fracture features were consistent with overstress separation.