Accident Details
On June 25, 2008, at 1346 eastern daylight time, a Cessna 172M, registration N13105, was substantially damaged during takeoff from Robert J. Miller Airpark (MJX), Toms River, New Jersey. The certificated flight instructor (CFI) and student pilot received minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight destined for Lakehurst Naval Air Station/Maxwell Field (NEL), Lakehurst, New Jersey. The flight was conducted under Title 14 Code of Federal Regulations Part 91 and operated by a Flying Club for flight training.
Narrative
According to the CFI, the student pilot was at the controls during the takeoff, demonstrating a soft-field takeoff. As the airplane's nose lifted off the runway, the CFI's seat rolled backward, and he instinctively reached for the control yoke. The airplane then yawed to the left, and the left wing struck the ground. Upon impact, the airplane spun around, the nose wheel impacted a rut in the grass, and the airplane flipped over.
The CFI stated he "distinctly remembered adjusting the seat forward" prior to taxiing, as it had been moved backwards to exit the airplane after landing. The CFI reported "shaking the seat" to assure it was in the locked position.
The student pilot stated he observed the CFI "rocking his seat to ensure it was secure" during the preflight. During the takeoff, the student pilot heard a noise which he thought was the tail scraping the runway, followed by the CFI stating his "seat was rolling back."
After the airplane came to rest inverted, the student pilot remained strapped into his seat by the seatbelt and shoulder harness; however, his seat was separated from the floor during the accident sequence. The student pilot noted the CFI was secured by his seatbelt and shoulder harness, and that the CFI's seat remained attached to the floor. The student pilot removed his seat from the airplane during egress.
Aircraft Examination
Examination by a Federal Aviation Administration (FAA) inspector and a Cessna Aircraft representative revealed the forward portion of the seat tracks for seat No. 1 (student pilot's seat) were cracked and slightly deformed upwards at the fifth adjustment hole. The aft portion of both tracks displayed impact damage consistent with the shape of the aft roller housings. The cap on the outboard track had wear grooves. The guide holes for the adjustment pin displayed oblong wear, and the bottom of the track holes exhibited wear spots. The adjustment pins were not bent, the roll pins were installed, and the spring was intact.
The forward portion of the seat tracks for seat No. 2 (CFI's seat) were also cracked and slightly deformed upwards at the fifth adjustment hole. All four roller housing tangs (feet) were spread and bent. The front feet were off the track, while the two rear feet remained partially attached. The tracks were gouged where in contact with the rear seat legs. The guide holes for the adjustment pins displayed oblong wear, and the bottom of the track holes had wear spots. The adjustment pins were not bent, the spring was intact with strong tension.
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. "Excessive wear" was noted to the seat track cap widths and the roller housing tangs.
The airplane sustained substantial damage to the vertical stabilizer, rudder, and left wing.
Maintenance Records
The airplane's maintenance records showed it had accumulated 8,631 hours of total time. The seat tracks were replaced on July 23, 1993 at 6,019 hours total time. The Seat Track Inspection Airworthiness Directive (AD) 87-20-03R2 was complied with during the most recent annual inspection on June 16, 2007 at 8,541 hours total flight time. The AD required inspection of the seat tracks; specifically the holes in each track for excessive wear, dirt or debris, and limited vertical play. The AD did not require inspection for excessive wear to the seat track cap widths and the tangs of the seat housings. Inspection time and date criteria outlined in the AD required that aircraft operated under Part 91 regulations (not for hire) only required the inspection after accumulation of 1,000 hours, at the next annual inspection, and each subsequent annual inspection.
Pilot Information
The CFI held a commercial pilot certificate with ratings for single-engine and multiengine land and instrument airplane. He also held a flight instructor certificate with a rating for airplane single-engine land. The CFI reported approximately 6,153 hours of total flight experience, 1,018 of which were in the Cessna 172. The CFI's most recent second-class medical certificate was issued on June 29, 2007, at which time he reported a weight of 235 pounds.
The student pilot reported 92 hours of total flight experience, 91 of which were in the Cessna 172. His most recent third-class medical certificate was issued on July 15, 2006, at which time he reported a weight of 250 pounds.
Weather
The winds reported at the airport at 1335 were from 280 degrees at 9 knots, gusting to 14 knots.