CEN18LA250

The airline transport pilot was conducting a personal flight when the airplane rolled left during the landing flare and then landed hard on the left main landing gear (MLG). The airplane bounced and landed hard and then bounced again on the left MLG. The left MLG spring separated from the fuselage on the third contact with the runway. The airplane subsequently ground looped to the left and came to rest heading about 180° from the original runway direction. The left main wing spar was substantially damaged when the left wingtip impacted the runway. Postaccident materials examination of the fractured left MLG spring revealed a multiple-origin fatigue crack where the landing gear fixation hardware contacted the landing gear spring. The maintenance logbooks were not complete; therefore, it could not be determined if the left MLG spring had been replaced or overhauled since new. The separation of the left MLG gear spring during landing was likely due to the fatigue crack that reduced the overall strength of the landing gear spring.

On July 1, 2018, about 2010 central daylight time, a Cessna 180 single-engine airplane, N2469C, was substantially damaged while landing at Rusty Allen Airport (RYW), Lago Vista, Texas. The airline transport pilot and passenger were not injured. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the personal flight that departed Childress Municipal Airport (CDS), Childress, Texas, about 1740 with RYW as the intended destination.According to the pilot, the surface wind was from 120° magnetic at 7 knots, gusting 17 knots, when he entered the traffic pattern for runway 15 at RYW. He noted that the wind direction became variable between 090° magnetic and 170° magnetic while the airplane was on the downwind leg. The pilot made a normal approach for three-point landing with a left crosswind correction; however, the airplane rolled left during the landing flare and landed hard on the left main landing gear. The pilot reported that the airplane bounced and that he was unable to regain roll control before the airplane landed hard again on the left main landing gear. The airplane bounced a second time and the left main landing gear spring separated from the fuselage on the third contact with the runway. The airplane subsequently ground-looped to the left and came to rest heading about 180° from the original runway direction. The left main wing spar was substantially damaged when the left wingtip impacted the runway. The fractured left main landing gear spring was examined by the National Transportation Safety Board Materials Laboratory to determine if preexisting damage had contributed to its separation during the accident. The laboratory examination revealed a fracture surface that exhibited a relatively flat surface with a distinct shear lip along the periphery. Further examination of the fracture surface revealed a chevron pattern indicating the direction of crack propagation from a thumbnail shaped initiation point. The location of the fatigue crack was adjacent to where the landing gear fixation hardware contacted the landing gear spring. The initiation point exhibited features consistent with a multiple-origin fatigue crack. The approximate dimension of the fatigue crack was 0.14 inch wide and 0.04 inch deep. The pilot stated that the airplane logbooks are not complete; however, there was no documented work on the left landing gear since the logbooks began in 1993. Based on the available information, the pilot estimated that the airplane had accumulated a total service time of about 4,101 hours. Based on a lack of complete maintenance documentation, it is unknown if the left main landing gear spring had been replaced or overhauled since new.