Accident Overview
On April 16, 2010, at approximately 1520 eastern daylight time, a Piper PA-46-350P, registration N779MA, operated by P & C Aviation LLC, was substantially damaged when the nose landing gear collapsed during landing at Parkersburg, West Virginia (PKB). The commercial pilot and one passenger were not injured. Visual meteorological conditions prevailed, and an instrument flight rules flight plan had been filed. The flight was conducted under Part 91 as a business flight.
Pilot Report
The pilot stated that the main landing gear touched down normally on runway 21. When the nose gear was lowered to the runway, the airplane veered sharply to the right. The pilot applied full left rudder to maintain directional control, but as the airplane slowed and rudder effectiveness decreased, the airplane departed the right side of the runway into the grass.
Examination of the Wreckage
A Federal Aviation Administration inspector examined the aircraft at the accident site. The structure around the nose gear and engine mount sustained substantial damage. A preliminary inspection of the nose landing gear showed fractured attachment components between the nose landing gear actuator and the engine mount. The affected parts were photographed, and the engine mount was removed for detailed examination at the NTSB Materials Laboratory.
NTSB Materials Laboratory Findings
The engine mount was a welded tubular construction with attachment feet at the aft end. Each foot was made by welding a tube to a disk, an older design; newer designs use a single machined piece. The right attachment foot had completely separated from its support tubes. The left attachment foot had separated from two of its three support tubes, and the remaining tube was bent.
On the right attachment foot, the fracture surface showed smooth, curving crack arrest markings consistent with fatigue cracking that originated at multiple points along the weld toe between the foot and the support tube. The fatigue crack propagated through the base metal of the foot over an arc length of about 0.75 inch and penetrated at least 0.04 inch through the estimated 0.06-inch wall thickness. Significant oxidation was present on this fracture surface.
On the left attachment foot, similar fatigue cracking was found along the lower inner edge where the foot was welded to the center support tube. The crack originated at multiple points along the weld and extended through the base metal of the center support tube and into the weld metal between the center and bottom tubes. The crack area was about 0.35 inch long and up to 0.03 inch deep. Little oxidation was present. No welding deficiencies were observed in the welds of either attachment foot.
Service Bulletin Compliance
Starting in April 2002, Piper Aircraft issued mandatory Service Bulletin (SB) 1103 and its revisions (A, B, C) for PA-46-350P models. These bulletins required repetitive inspections for cracks in the engine mount at the nose landing gear actuator attachment feet. Inspections were to be performed at each 100-hour or annual inspection, whichever came first. Replacement of the engine mount with a newer design featuring one-piece attachment feet would eliminate the repetitive inspection requirement. The accident aircraft retained the older welded two-piece feet, so it remained subject to the inspection requirements.
Maintenance Records
Review of the aircraft maintenance logbooks showed that SB 1103B was completed during an annual inspection on May 4, 2007. However, the subsequent annual inspections on May 1, 2008, and June 5, 2009, did not include the required SB 1103 inspections. The operator did not provide an explanation for the omission.