This July 2009 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Piper Malibu. Injuries: None. Location: Westley, Calif. Aircraft damage: .Substantial
What reportedly happened: The pilots encountered smoke in the cockpit originating from the area of the copilot’s rudder pedals. The pilots performed the emergency procedures for an electrical fire, which included shutting down the electrical systems. The smoke seemed to initially subside, but then gradually intensified before the engine lost power. The pilots were unable to restart the engine and decided to concentrate on making an off-airport landing. While landing in a plowed field, the nosewheel collapsed.
A post-accident examination revealed extensive fire damage to the rear of the engine and to the firewall. The nose gear hydraulic actuator flexible hose assembly also sustained extensive fire damage consistent with being near the source of the fire.
Further inspection found that the nose gear hydraulic down line remained attached at both attachment fittings. The flexible hose assembly installed on the nose gear actuator uses an AN-style B-nut fitting. The internally threaded hose socket is screwed onto the end of the hose, and the B-nut is secured to the actuator fitting by an externally threaded nipple. Closer examination of the hydraulic line fitting where it attaches to the actuator revealed a crack running along the entire length of the socket. The hose remained inserted into the socket, but because of the crack, the socket fitting could be turned by hand on the hose. The nose gear actuator hydraulic line was then removed. The hose end was easily pulled out and separated from the socket.
The manufacturer’s identification band indicated that the hose assembly was manufactured in the third quarter of 1991. A review of the scheduled maintenance section of the PA-46-310P maintenance manual in the landing gear group section states, in part, to “Replace flexible hoses as required, but no later than 1,000 hours of operation or eight years and at engine overhaul.” Although the identification band on the hose assembly indicated that it was manufactured in 1991, no log book entry was located indicating that the hose assembly had ever been replaced.
Probable cause: The failure of the landing gear hydraulic line socket, which resulted in a hydraulic leak and in-flight fire. Contributing to the accident was the failure of the owner and/or maintenance facility to comply with the maintenance manual hose replacement schedule.
For more information: NTSB.gov NTSB Identification: WPR09LA341
