Beech 58 N4626A accident near Cahokia, Illinois

Probable cause

Maintenance personnel's improper replacement of the landing gear leg brace assembly which subsequently failed to keep the landing gear in the locked position.

NTSB analysis

The pilot reported that while landing, during the post maintenance test flight, he felt "a falling motion to the back right." He aborted the landing and flew by the control tower for a landing gear check. He was informed the landing gear appeared down. He then returned to his departure airport and while landing there he felt the right wing drop closer to the ground than normal. He aborted the landing again and began to troubleshoot the landing gear system. The pilot flew by the air traffic control tower two more times and performed the Emergency Gear Extension checklist. The pilot then used the Gear-Up Landing emergency checklist and landed the airplane. During the landing roll the right main gear collapsed and the right wing contacted the runway. As a result, the right wing and aileron were substantially damaged. The pilot reported that he had received a gear down and locked indication every time he extended the landing gear during the flight. The post accident inspection of the landing gear revealed that it could be released from the down and locked position by pushing on it with hand pressure. The leg brace portion of the landing gear retract brace assembly was replaced during the annual inspection. The leg brace that was installed was not purchased from Beechcraft. According to Beechcraft they do not sell the leg brace as a separate item from the upper brace assembly because of the close tolerance required between the two braces in order for the gear to properly lock in the extended position. There is no information in the BE-58 maintenance manual which indicating that the upper brace assembly and the leg brace must be replaced as a unit for the main landing gear.

Text from the NTSB. Open the NTSB docket for CHI08LA070 for the full record.