Piper Malibu Meridian PA-46-500TP, Parowan, Utah, Jan. 16, 2007–The NTSB determined that the runway overrun of the Malibu Meridian at Parowan Airport was due to the inadequate design of the engine mount, which caused an uncommanded left turn during the landing roll and loss of directional control. The Meridian hit a snow bank. No one was injured in the accident. Investigators found that the rear actuator bolt on the nosegear had failed and that the engine mount was bent near the nosegear actuator attach feet.
The ATP-rated pilot told investigators that on approach the red gear warning light came on for about four to six minutes, but then went off. He mentioned several previous instances of the warning light coming on in flight, and once after the landing gear was lowered. He also said that on two or three previous landings the airplane had pulled to the left on taxi, takeoff and landing.
Previous PA-46-500TP nosegear failures caused runway excursions with a high-speed shimmy and subsequent uncommanded left or right turn of the nosewheel during takeoff and/or landing. This resulted in Piper Service Bulletin (SB) 1154A, requiring a 100-hour inspection for cracks due to flexibility in the engine mount actuator attach structure. The operator had recently complied with the SB on the accident airplane, which had accumulated a total of 181 hours, with “no cracks or defects noted.”
On March 28, 2007 Piper issued SB 1154B, which shortened the repetitive inspection requirement for the engine mount from 100 hours to 50 hours. A redesign of the original engine mount feet structure substitutes a one-piece design at the actuator attach point, eliminating the two-piece design, which allowed relative motion between the two feet. Installing P/N 102460-036 prevents relative motion between the two feet in the original engine mount design and eliminates the inspection requirement. According to Piper, all original mounts will be removed and replaced with the new design by next month; as of March, 107 PA-46-500TPs needed the engine mount replaced. Piper said that it has contacted all PA-46-500TP customers regarding the replacement of the mount and developed a replacement schedule.