This April 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 Family Cruiser. Injuries: None. Location: Anchorage, Alaska. Aircraft damage: Substantial.
What reportedly happened: The private pilot said that as he applied power his seat slid back and he was unable to reach the rudder pedals to maintain directional control. The airplane ground-looped and the right wing hit the ground.
An FAA inspector who examined the airplane said that the front seats had been modified with adjustable seat tracks with FAA field approval. The mechanical seat stop, which was supposed to be installed on the left track, had been installed on the right track. The stop was needed to keep the seat from being pulled too far forward. Because the stop was installed on the wrong track, the inspector said the pilot was able to pull the seat locking pin forward of the last locking hole. The locking pin fell between two screw heads, giving it the feeling of being secured. He said that during acceleration, the locking pin jumped over the screw head and the seat slid back.
Probable cause: The pilot’s inability to maintain directional control due to the seat sliding back during takeoff as a result of maintenance personnel’s incorrect installation of the seat’s forward track stop.
For more information: NTSB.gov