N4837ZPiper PA-22-108 · 1961

On March 16, 2020, about 1720 mountain daylight time, a Piper PA-22-108, N4837Z, was substantially damaged when it was involved in an accident near Pinedale, Wyoming. The student pilot had minor injuries and the flight instructor was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.

The student pilot reported that the flight instructor took control of the airplane on final approach to runway 29 because the airplane was drifting to the right. The flight instructor later reported that after he took control of the airplane, he applied rudder control inputs. He reported that during a 6-to-7-second time period, the rudder pedals would not move. The airplane did not align with the runway and soon after impacted terrain near the runway.

Examination of the recovered airframe by an airframe and powerplant mechanic revealed substantial impact damage to both wings, fuselage and engine mount. The left wing, from the side strut to the tip was partially separated due to the impact with the ground during the accident sequence. The left aileron inboard attachment bracket separated from the left aileron bellcrank. Corrosion was noted between the aileron bracket and aileron bellcrank mounting surfaces. The remaining rivet material left in the aileron and bellcrank bracket exhibited overload necking signatures. The airplane's flight control cables were intact. The rudder control cable rear pulleys were unable to be rotated freely by hand. During the flight control cable continuity check, the cables moved past the pulleys with little resistance. Nothing was impeding the rudder pedals from their normal movement. In another follow-up examination, the pulleys were stiff when rotated by hand and the cables were undamaged.

The flight instructor reported that he thought that the glareshield mounted tachometer timing box could have been trapped behind the rudder pedals. The tachometer timing box was located at the accident site and had been thrown from the wreckage. A portion of the instrument panel mounted tachometer housing was found behind the rudder pedals. Further examination of the tachometer gauge revealed damage consisted with impact damage as a result of the accident.

An NTSB Form 6120.1 Pilot/Operator Aircraft Accident/Incident Report was not summited by the student pilot or the flight instructor.