Cessna 172M N13105 accident near Toms River, New Jersey

Probable cause

The failure of the pilot's seat to engage or remain engaged due to the improper inspection of the worn seat tracks.

NTSB analysis

During a soft-field takeoff demonstrated by the student pilot, the certificated flight instructor's(CFI's) seat rolled backward, and he instinctively reached for the control yoke. The airplane yawed to the left, the left wing struck the ground, and the airplane flipped over. The CFI stated that he adjusted the seat forward prior to taxiing the airplane to the runway and recalled "shaking the seat" to assure it was in the locked position. Examination of the seat tracks for the CFI's seat revealed that all four roller housing tangs (feet) were spread and bent, and the corresponding locations on the seat tracks were gouged. Examination of the seat tracks for both seats revealed several seat pin adjustment holes exceeded the dimensions for acceptable wear as described in the Cessna Service Manual, and "excessive wear" was noted to the seat track cap widths and the roller housing tangs. An Airworthiness Directive (AD) which required inspection of the seat tracks was completed 90 hours prior to the accident. The AD did not require inspection for excessive wear to the seat track cap widths and the tangs of the seat housings.

Text from the NTSB. Open the NTSB docket for NYC08LA228 for the full record.