CEN18LA230

The private pilot was practicing takeoffs and landings in the airport traffic pattern when the left main landing gear (MLG) failed to extend. He cycled the gear, but the left MLG still would not extend. He then attempted to manually extend the gear without success. The pilot subsequently executed an emergency landing on the turf runway. During recovery of the airplane, one of the left brake caliper's back plate bolts was found backed out. Scrape marks were present on the fuselage skin, consistent with contact from the extended back plate bolt. The MLG extension/retraction system and the emergency extension system both performed normally during postaccident examination. An annual inspection had been completed 6 days before the accident, and the airplane had accumulated a total of 3.2 hours since then. The mechanic that performed the inspection reported that the brake calipers were removed at that time and that the bolts had not been secured with safety wire after they were re-installed. Given the evidence, it is likely that the mechanic did not properly torque the left brake caliper back plate bolt after he re-installed it during the annual inspection, which allowed it to back out and led to the subsequent failure of the left MLG to extend. Although safety wire would have prevented the bolt from backing out, the airframe manufacturer's service manual was not consistent about whether to use safety wire. Regardless, the bolt would not have backed out if it had been tightened within the specified torque.

On June 18, 2018, about 1230 central daylight time, a Cessna TR182 airplane, N756SW, was substantially damaged during an emergency landing on runway 22 (2,381 ft by 110 ft, turf) at the Moritz Memorial Airport (K61), Beloit, Kansas. The pilot was not injured. The airplane was registered to and operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed. The flight was not operated on a flight plan. The local flight originated from K61 about 1140.The pilot reported that he was conducting takeoffs and landings in the traffic pattern when the left main landing gear failed to extend. He had not experienced any problems with the landing gear prior to that point during the flight. He remained in the traffic pattern and cycled the landing gear but the left main landing gear would not extend. He also attempted to use the manual gear extension without success. He decided to execute an emergency landing on the turf runway. The left horizontal stabilizer and elevator contacted the ground during the emergency landing resulting in substantial damage to the airplane. The airplane was recovered from the accident site by the owner/pilot and a local mechanic. The mechanic had recently completed an annual inspection on the airplane. During recovery, they noted that one of the brake caliper attachment bolts had backed out about 3 or 4 turns, which caused the bolt to protrude about 1/4-inch. It appeared that the protruding bolt had caught on the fuselage skin at the perimeter of the wheel well causing the left main landing gear to remain retracted. The left brake caliper and wheel assembly was removed to facilitate recovery. A postaccident examination conducted by a Federal Aviation Administration inspector did not reveal any anomalies with respect to the normal landing gear extension/retraction system, or with the emergency extension system. The inspector noted that about 1/2-inch of clearance existed between the wheel well opening and the brake caliper back plate bolts when the landing gear was retracted. The fuselage skin exhibited scrape marks in the vicinity of the back plate bolt when the landing gear was retracted. The inspector noted that the bolts on the right brake caliper back plate were not safety wired at the time of the examination. The airplane maintenance records noted that an annual inspection was completed on June 12, 2018; 6 days before the accident. A total of 3.2 hours had accumulated since the inspection. The entry indicated testing of the landing gear extension/retraction and emergency extension systems were completed. The mechanic informed the inspector that the brake calipers were removed during the annual inspection and that the bolts had not been secured with safety wire after they were re-installed. The Cessna TR182 service manual noted, in figure 5.10, that the brake caliper back plate bolts should be torqued to 100 – 110 in-lbs and safety wired. In section5-169, Brake Installation, the service manual stated that the back plate bolts should be torqued to 110 – 120 in-lbs. The use of safety wire was not mentioned in section 5-169.