Accident Overview
On October 19, 2014, about 1805 eastern daylight time, a Cessna 172K airplane, registration N79534, was substantially damaged during a loss of control on takeoff at the Greene County-Lewis A. Jackson Regional Airport (I19), near Xenia, Ohio. The pilot, the sole occupant, received serious injuries. The aircraft was registered to and operated by MacAir Aviation LLC under 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed, and the flight was not on a flight plan. The local flight was originating at the time of the accident.
Sequence of Events
The pilot reported that during takeoff rotation, the seat unexpectedly slid rearward and the seat back tipped aft. This led to his inadvertent application of rearward yoke, inability to reach the rudder pedals, and subsequent loss of control. The airplane departed the left side of the runway and struck a ditch bank, resulting in substantial damage.
Maintenance History
Aircraft records indicated that on the day before the accident, a different pilot had entered a maintenance discrepancy noting that the left seat slid back three times during flight. The following day, before the accident flight, a mechanic repaired the hold-down spring and returned the airplane to service. After that repair, another pilot noted that the left front seat was in the reclined position and would not lock in the upright position. This discrepancy was not corrected before the accident. It was undetermined if the accident pilot was aware of these previous reports.
Postaccident Examination
Postaccident examination revealed a deformed metal tang adjacent to the forward outboard seat track roller. The tang was part of the seat base, and the formed lip retained the seat base to the T-shaped seat track. The deformation was consistent with lateral force. It could not be determined if the deformation existed during the required inspection under Airworthiness Directive (AD) 2011-10-09. The forward outboard position also retained the pin mechanism for fore-aft seat adjustment, which engaged holes in the track to lock position. Examination also showed the pilot's seat back structure could not be locked in any position; no determination was made as to why.
Airworthiness Directive Compliance
The seat mechanism was subject to AD 2011-10-09, issued by the FAA to prevent seat slippage or roller housing departure from the seat rail. The AD stated such failure could cause loss of control. It required repetitive inspections, including checking tang length. Review of the AD compliance sheet for the accident airplane confirmed that the inspections had been completed within the required time frame.