ERA15LA268

The airline transport pilot was conducting a personal cross-country flight in the tailwheel-equipped airplane. The pilot reported that he performed a wheel landing, during which a light quartering tailwind existed. As the tailwheel touched down on the runway, the airplane began drifting right. The pilot unsuccessfully attempted to correct the drift by applying left rudder and then left brake. Shortly thereafter, the pilot heard a loud "bang," and the airplane then ground looped left, which resulted in substantial damage to the airframe. Postaccident examination of the airplane revealed that the left main landing gear wheel had separated from the landing gear leg. Further examination revealed that two of the four bolts that attached the left main landing gear wheel assembly to the landing gear axle had failed. Examination of the bolts' fracture surfaces revealed signatures consistent with an overload-induced failure due to bending. No evidence of any preexisting corrosion or fatigue of the bolts was observed.

On July 10, 2015, about 1350 eastern daylight time, a Cessna 170B, Canadian Registration C-FHER, was substantially damaged during a loss of control on landing at Buffalo Niagara International Airport (BUF), Buffalo, New York. The airline transport pilot was not injured. Visual meteorological conditions prevailed, and a visual flight rules flight plan was filed for the personal flight, which departed from Burlington Airpark (CZBA), Burlington, Ontario, Canada, and was operated under the provisions of Title 14 Code of Federal Regulations Part 91. According to the pilot, automated terminal information service was reporting light winds favoring runway 23, but air traffic control offered him runway 14 for landing. On the short final leg of his approach to the runway, the pilot reported that he looked at the wind sock and noticed it was "hanging straight down." The airplane touched down about 200 feet from the runway threshold on the main landing gear, and as the tail wheel settled onto the runway, the airplane drifted to the right. The pilot attempted to correct with left rudder and then left brake. The pilot stated that as he continued to apply the left brake, he heard a loud "bang" and the airplane ground looped, but he could not determine what the origin of the sound was, or what precipitated the ground loop. Post-accident examination of the airplane revealed substantial damage to the left wing, left elevator, and fuselage. The outboard portion of the left wing spar was damaged, the left elevator was crumpled, and the fuselage landing gear box where the left spring gear was attached was damaged. The left wheel and hub assembly detached from the landing gear post during the accident sequence and came to rest about 10 feet from the airplane. In addition, there was a 3-foot long gouge in the pavement where the gear post scraped the runway, near where the airplane came to rest. The weather reported at BUF, at 1354, included variable winds at 6 knots. In the two hours leading up to the accident, winds were from a 250 degrees true at 4 knots and 260 degrees true at 4 knots, respectively. The hour after the accident, winds were reported from 250 degrees true at 7 knots. The pilot held a Canadian airline transport pilot license with ratings for aeroplane single and multi-engine land. His most recent flight review was completed on March 25, 2015. He reported 12,400 total hours of flight experience, of which 750 hours were in the accident airplane make and model. His most recent Transport Canada Civil Aviation first-class medical certificate was issued July 26, 2014. A review of the airplane's maintenance records showed the most recent 100-hour inspection was completed on December 19, 2014 at 4,190 airframe hours. At the time of the inspection no anomalies were discovered. On January 12, 2015, the Fly Lite 3000 Mark III hydraulic wheel skis were removed. The airplane was operated for an additional 27 hours and 71 landings with no anomalies reported by thepilot or documented in the maintenance records. The left landing gear wheel and hub attachment bolts were retained for detailed examination. Two of the four bolts were fractured during the accident sequence. Detailed examination of the fracture faces of the bolts showed angular necking features of the bolt cross sections adjacent to the fracture. The remaining two bolts had not fractured. None of the bolts displayed any evidence of corrosion or fatigue-induced failure.