NTSB Factual Report

On June 4, 2012, about 1825 Pacific daylight time, a Piper PA46R-350T, N488EA, experienced a collapse of the nose landing gear at Cameron Airpark, Cameron Park, California. The private pilot, who was the sole occupant, was not injured, but the airplane, which was owned and operated by the pilot, sustained substantial damage. The 14 Code of Federal Regulations Part 91 personal flight, which departed Palo Alto Airport, Palo Alto, California, about 55 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed.

According to the pilot, he made a normal uneventful landing, but during the landing roll the airplane's nose landing gear collapsed. After the collapse of the nose gear, the airplane temporarily departed the runway and encountered soft terrain, but the pilot was then able to bring it back onto the runway surface before it came to a stop. According to the Federal Aviation Inspector who responded to the scene, a part of the gear actuation and support system had separated from the location where it was attached to the engine mount, allowing the nose gear to partially retract, and resulting in a portion of the actuating system coming in contact with the firewall. The airplane was recovered to an on-field maintenance shop, where it underwent further examination. The examination of the airplane, which was under the direct supervision of a Federal Aviation Administration (FAA) Inspector assigned to the Sacramento Flight Standards District Office, revealed that the right side gear actuator attach foot had fractured and separated from the engine mount. The actuator then moved upward and aft, which allowed the nose landing gear to partially retract. As a result of the forces generated by the partial retraction of the nose landing gear, and the departure of the airplane from the runway, several engine mount braces were found either bent or broken. During this sequence of events, the engine firewall was substantially damaged. A field examination of the fractured metal tube revealed that a majority of the fracture face around its circumference showed a rough granular surface with a 45 degree fracture angle consistent with overload failure. A short section of the fracture, approximately 3/8 inch long, revealed the smoother shiny surface with beach marks and an area of pre-failure oxidation consistent with the propagation of a fatigue crack.

A review of the airframe log book indicated that Piper Aircraft Service Bulletin 1103D (SB 1103D), issued on February 2, 2011, concerning the repetitive 100-hour inspection of the engine mount assembly for cracks, was complied with during an Annual Inspection performed on March 15, 2011. At the time of that inspection the airplane had accumulated 617.6 total hours. According to the inspection log entry no defects were found. The aircraft received its next Annual Inspection on March 9, 2012, and according to the log book, at that time the airplane had accumulated 888.3 total hours. The log book entry from that Annual Inspection did not reference any compliance actions associated with SB 1103D, and there were no other subsequent entries referencing compliance with SB 1103D in the airplane’s log book. At the time of the accident, the airplane had accumulated 930 hours total time, and 313 hours since the last time SB 1103D was complied with.

The investigation determined that although Piper Aircraft Company considers their Service Bulletins to be mandatory actions, the FAA does not require that they be complied with for aircraft that are used exclusively for FAR Part 91 operations, as this airplane was. Therefore, neither the owner of the airplane or the maintenance shops performing the annual inspections were required to make sure the actions called for by SB 1103D were complied with. However, failure to comply with SB 1103D could create the situation where fatigue cracks that would have been detected during SB 1103D compliance actions might go undetected, and eventually lead to the failure of a component of the engine mount/gear support assembly.

NTSB Probable Cause

The fatigue failure of the nose landing gear actuator attach foot during the landing roll. Contributing to the accident was the non-compliance with the manufacturer’s service bulletin.