Burlington, VT, USA
N8025M
CESSNA 310I
The pilot reported that he landed the multiengine airplane without incident and while taxiing, the left main landing gear collapsed, which resulted in substantial damage to the left wing and left horizontal stabilizer. Subsequent examination of the airplane revealed that the left main gear bellcrank pin separated from its bushing. The pin was not located; however, metallurgical examination of the left main gear bellcrank and retraction link revealed significant deformation and fracturing of the bellcrank bushing consistent with a very large force applied along the axis of the link. The deformations on the link bore suggested the pin fractured inside the hole and exited the bore as two separated pieces. While overstress conditions seem probable, other failure modes, such as a significant fatigue crack cannot be ruled out since the pin fragments were not located. The airplane was manufactured about 38 years prior to the accident. It had been operated for about 3,675 total hours and 25 hours since its most recent annual inspection, which was performed about 2 months earlier.
On October 2, 2012, about 0900 eastern daylight time, a Cessna 310I, N8025M, operated by a private individual, was substantially damaged while taxiing after landing at the Burlington International Airport (BTV), Burlington, Vermont. The private pilot and a passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the local personal flight that was conducted under the provisions of 14 Code of Federal Regulations Part 91. According to the pilot, the airplane landed on runway 15, an 8,320-foot-long, asphalt and concrete runway without incident. He taxied toward the end of the runway and was making a right turn onto taxiway "C" when the left landing gear began to collapse. The left side of the airplane struck the ground, which resulted in substantial damage to the left wing and left horizontal stabilizer. Subsequent examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed that the left main gear bellcrank pin separated from its bushing. The pin was not located; however, the left main gear bellcrank and retraction link were removed and forwarded to the NTSB Materials Laboratory, Washington, D.C., for examination. The airplane was manufactured in 1964. According to an FAA inspector, at the time of the accident, the airplane had been operated for about 3,675 total hours and 25 hours since its most recent annual inspection, which was performed on August 8, 2012. Metallurgical examination revealed that the bellcrank and retraction link were connected by a pin inserted through a clevis on the long arm of the bellcrank and a pivot hole on the retraction link. One of the clevis tangs was bent outward and contained a small crack. Both flange bushings were fractured in similar manners on the inside of the clevis and the liberated halves of the bushings displayed features consistent with overstress, with no evidence of progressive cracking. The edges of the inner bore of the pivot hole in the retraction link were locally deformed radially outward in one direction on each side of the link, consistent with pin contact. [Additional information can be found in the Materials Laboratory Factual Report located in the public docket.] According to a representative from Cessna Aircraft Company, Cessna was not aware of any previous failures or separations involving only the main landing gear bellcrank pin on Cessna 310 series airplanes.
The collapse of the left main landing gear due to a failure of the left main gear bellcrank pin for reasons that could not be determined because the pieces of the fractured bellcrank pin were not located.
Source: NTSB Aviation Accident Database
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