Accident
An agricultural airplane experienced a runway excursion during the landing roll. The aircraft departed the right side of the runway, entered soft terrain, and subsequently nosed over to an inverted position.
Pilot Report
The pilot reported that during the landing roll, his seat became dislodged from the seat track. He further stated that because his left leg is shorter than his right leg, when the seat slid all the way back, his left foot lost contact with the rudder pedal.
Examination
An FAA inspector examined the seat and found that the forward left seat roller housing assembly had spread open to nearly the width of the seat rail. This condition allowed the seat to dislodge from its locked position.
Maintenance Records
According to the inspector, the airplane's maintenance records indicated compliance with Airworthiness Directive (AD) 87-20-03 R2 at the last annual inspection. AD 87-20-03 R2 is intended to ensure proper engagement of the seat locking mechanism and to prevent inadvertent seat slippage. However, the inspector determined that the AD had not been properly accomplished, as the seat did not meet the locking pin engagement requirements specified in the AD. The time since the last annual inspection was 249.4 hours.