Smith Valley, NV, USA
N1875N
CESSNA 120
The pilot reported that the airplane bounced during the landing, and when it touched down again, it veered to the left. The pilot applied power to abort the landing, but the airplane continued off the left side of the runway surface into sagebrush. Postaccident examination revealed that the right main landing gear strut was transversely fractured through the upper attachment hole for the step bracket. Subsequent metallurgical examination revealed that the fracture surface was indicative of fatigue and originated in an area of corrosion.
On June 8, 2012, about 1015 Pacific daylight time, a Cessna 120, N1875N, experienced a runway excursion during landing at Farias Wheel Airport (NV33), Smith Valley, Nevada. Valley View Flyers LLC was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot was not injured; the airplane sustained substantial damage. The cross-country personal flight departed Yerington, Nevada, about 0955, with a planned destination of NV33. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that during landing the airplane bounced; when it touched down again, it suddenly veered to the left. He applied power to abort the landing, but the airplane continued left, and departed the runway surface into sagebrush. The right main landing gear collapsed, and the right wing and the propeller contacted the ground. The pilot turned off the master switch, shut off the fuel, and exited the airplane. A Federal Aviation Administration (FAA) inspector examined the wreckage on site. He noted that the fracture surface of the right main landing gear was flat with beach marks. The part was submitted to the National Transportation Safety Board (NTSB) Materials Laboratory for examination. An NTSB metallurgist observed that the main landing gear strut was transversely fractured through the upper attachment hole for the step bracket. The upper fracture face was mechanically damaged, while the lower face was mostly undamaged. Optical examinations of the fractured face revealed chevron markings indicative of fracture initiation on both sides of the hole at the corners formed by the hole’s bore and the upper surface of the strut. Closer magnified examinations uncovered small fatigue cracks at both corners of the hole. The fatigue on the forward side of the hole initiated at three locations in a corrosion pitted area of the bore surface. The aft fatigue region initiated at a single origin at the corner in a corroded area. Corrosion was visible in unpainted areas. Removing the remnant paint from the bore revealed corrosion and corrosion pitting over the entire bore surface. The airplane was built in 1946, and had a total airframe time of 8,934 hours.
The failure of the right main landing gear strut due to corrosion-induced fatigue, which resulted in a runway excursion.
Source: NTSB Aviation Accident Database
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