Air Accidents Investigation Branch
Summary:
The pilot reported that the landing was normal, but the right main landing gear collapsed rearwards as the aircraft slowed during the rollout. The pilot was uninjured.
Investigation by the aircraft operators maintenance agency identified that the right main landing gear drag bolt had broken. Similar failures have occurred on other PA-23 type aircraft, and the manufacturer issued Service Bulletin 1299 in January 2017 to periodically check (and replace) the bolts. The FAA issued Special Airworthiness Information Bulletin (SAIB) CE-17-08 in February 2017 recommending that operators comply with the manufacturers bulletin. They did not consider the failure to be an unsafe condition, so an Airworthiness Directive was not issued.
The aircraft operator told the AAIB that they periodically checked the bolts in accordance with the manufacturers recommendations, but no anomalies had been found. After the accident, they said that they will replace the drag bolts on all their PA-23 aircraft.