ANC19LA024

During landing on an unimproved runway, after the tailwheel contacted the ground, it’s mount failed, the rudder pedal jammed, and the airplane veered right. The pilot attempted to raise the tail to regain control with no effect. The airplane subsequently exited the intended landing area and came to rest in brush. A postaccident examination of the airplane revealed that the aft airframe tubing where the tailwheel was mounted to the airframe was corroded and fatigued, with cracks and discoloration from corrosion on the airframe. The airplane had flown 44.9 hours and 109 days had elapsed since its most recent annual inspection. Review of maintenance records revealed no discrepancies related to the area of the tailwheel mount. It is likely that the mechanic failed to conduct a detailed inspection in the aft fuselage area, which would have identified the corrosion.

On June 12, 2019, about 1930 Alaska daylight time, an Aeronca 7DC (Champ) airplane, N83391, sustained substantial damage, during an off-airport landing, following a loss of control after the tailwheel of the airplane separated from the fuselage near Nome Creek, Alaska. The private pilot and sole occupant sustained no injuries. The airplane was registered to the pilot and operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a visual flight rules personal flight. Day visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The flight originated from the Fairbanks International Airport (FAI), Fairbanks, Alaska, about 1830. The pilot reported that, after selecting a dry, unimproved dirt airstrip to land, he performed a wheel landing. When he lowered the tail during the landing roll, the rudder pedal jammed, and the airplane veered right. He attempted to raise the tail to regain rudder control, with no effect. The airplane exited the intended landing area and was headed toward trees, he pulled the throttle to idle, and applied aft pressure on the control stick while applying the brakes. Subsequently, the airplane stopped short of the tree line in the brush. The pilot further reported that during a postaccident inspection, the tailwheel had failed at the forward attach mount point, the tailwheel spring had dug into the ground, and the broken tailwheel had caught the rudder and had jammed it. The airplane was examined on June 18, 2019 by an NTSB senior aviation accident investigator in Fairbanks. The examination revealed the aft portion of the airframe was corroded, with the airframe tubes discolored and damaged from the corrosion. The location where the tailwheel mounted to the airframe had failed and showed positive signs of corrosion throughout the tubing. The last inspection on the airplane performed was an annual inspection dated February 23, 2019. Since the inspection, 109 days had elapsed, and the airplane had flown 44.9 hours. During the annual inspection, the mechanic noted that he shimmed the rudder up to prevent chaffing on the tail spring. He also noted that he shimmed the tailwheel spring to help with the geometry of the tailwheel.