Accident Overview
On June 4, 2012, at approximately 1825 Pacific daylight time, a Piper PA46R-350T (registration N488EA) experienced a collapse of the nose landing gear during the landing roll at Cameron Airpark, Cameron Park, California. The private pilot, the sole occupant, was not injured. The airplane, owned and operated by the pilot, sustained substantial damage. The flight was conducted under 14 Code of Federal Regulations Part 91 as a personal flight, having departed Palo Alto Airport, Palo Alto, California, about 55 minutes earlier. Visual meteorological conditions prevailed, and no flight plan was filed.
Landing and Gear Collapse
According to the pilot, the landing was normal and uneventful until, during the landing roll, the nose landing gear collapsed. Following the collapse, the airplane temporarily departed the runway and encountered soft terrain. The pilot was able to maneuver the airplane back onto the runway surface before it came to a stop.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector responded to the scene and noted that a part of the gear actuation and support system had separated from its attachment point on the engine mount. This separation allowed the nose gear to partially retract, bringing a portion of the actuating system into contact with the firewall. The airplane was recovered to an on-field maintenance shop for further examination.
Under the supervision of an FAA inspector from the Sacramento Flight Standards District Office, an examination revealed that the right side gear actuator attach foot had fractured and separated from the engine mount. The actuator then moved upward and aft, causing the nose landing gear to partially retract. The forces from this partial retraction, combined with the airplane's departure from the runway, resulted in several engine mount braces being bent or broken, and substantial damage to the engine firewall.
A field examination of the fractured metal tube showed that a majority of the fracture face had 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, exhibited a smoother shiny surface with beach marks and an area of pre-failure oxidation, indicative of a propagating fatigue crack.
Service Bulletin Compliance
A review of the airframe logbook indicated that Piper Aircraft Service Bulletin 1103D (SB 1103D), issued on February 2, 2011, addresses repetitive 100-hour inspections of the engine mount assembly for cracks. This service bulletin was complied with during an Annual Inspection performed on March 15, 2011, when the airplane had accumulated 617.6 total hours; no defects were found. The next Annual Inspection occurred on March 9, 2012, at which time the airplane had 888.3 total hours. The logbook entry for this inspection did not reference any compliance actions associated with SB 1103D, and no subsequent entries indicated further compliance. At the time of the accident, the airplane had accumulated 930 total hours and 313 hours since the last SB 1103D compliance.
Investigation Findings
The investigation determined that while Piper Aircraft Company considers their service bulletins mandatory, the FAA does not require compliance for aircraft operated exclusively under FAR Part 91, as this airplane was. Therefore, neither the owner nor the maintenance shops performing annual inspections were obligated to ensure compliance with SB 1103D. However, the investigation noted that failure to comply with SB 1103D could allow fatigue cracks that would have been detected during such inspections to go undetected, potentially leading to the failure of a component of the engine mount and gear support assembly.