Accident Overview
On August 31, 2011, at approximately 1630 eastern daylight time, a Cessna 172N, registration N739RU, was substantially damaged during landing at Plymouth Municipal Airport (PYM) in Plymouth, Massachusetts. The private pilot was not injured. The aircraft was registered to a private owner and operated by Alpha One Flight Service under 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan had been filed for the local flight.
Pilot Report
The pilot reported that she intended to conduct takeoff and landing practice in the airport traffic pattern. During the takeoff roll, she observed that forward pressure on the control column was required to prevent the aircraft from pitching up before reaching rotation speed. She stated she was not concerned about controllability and chose not to abort the takeoff. During the climb, nose-down trim was applied, but forward pressure remained necessary to maintain the correct pitch attitude. However, she told an FAA inspector that once airborne, everything seemed normal. During the landing flare, the pilot reduced engine power but found she could not pull back on the control column. The airplane bounced several times, each time impacting the nose landing gear before the main landing gear.
Pre-Accident Flight
According to a written statement from a certificated flight instructor who flew the same aircraft prior to the accident flight, he "did not find any discrepancies with the aircraft during preflight and the flight was uneventful."
Discovery and Examination
The accident was not reported to the FAA or the NTSB. Approximately two weeks after the event, an FAA inspector discovered the damaged airplane at the airport. Before this discovery, one of the flight school's mechanics had removed the engine cowling and noticed the firewall was damaged. He observed that the elevator trim was in a slight nose-up setting. He moved the trim wheel and noted that the elevator trim tab operated. He then disconnected the elevator push/pull rod that connected to the bellcrank and was able to move the elevator freely. He also noted slack in the elevator secondary control cables, which he attributed to structural damage.
Post-Accident Examination
Examination by an FAA inspector and an aircraft mechanic revealed that the firewall was buckled and the floor beneath the pilot and co-pilot seats was damaged. The elevator push/pull rod, connecting to the bellcrank, was disconnected, and the elevator moved without obstruction. The primary flight control cables remained connected at the elevator and bellcrank. There was no evidence of damage to the elevator control "U." Inspection behind the instrument panel found nothing that would interfere with control column travel. No indication of preimpact binding or damage was present. The aluminum channels connected at the instrument panel and the firewall remained attached at both ends by rivets but were bent downward, causing binding to the aileron chain sprockets. The instrument panel had shifted aft of its normal position. The elevator control cables were devoid of tension, preventing accurate deflection measurement of the elevator. Bearings and pulleys were free and showed no signs of prior damage.
Flight School Statement
In a written statement, a representative of the flight school reported no mechanical malfunctions or failures that would have precluded normal operation of the airplane.