What happened
On April 8, 2015, a Piper PA19 was conducting a training flight at the Saint-Gaudens Montréjeau aerodrome. The flight, involving an instructor and a student pilot, was intended to facilitate the student's solo endorsement on this aircraft type. The crew had completed two previous flights together, including a session the day prior involving full landings.
The flight plan for the day consisted of performing touch-and-go maneuvers. During the first attempt, the student successfully landed on the runway centerline without instructor intervention. However, as power was increased during the subsequent takeoff roll, the aircraft began to deviate to the right while in the three-point stance. The instructor intervened using the rudder pedals and reduced engine power to approximately 2,000 RPM to regain control.
Once a straight trajectory was briefly re-established, the instructor increased power again, intending to take advantage of increased control surface effectiveness at higher speeds. During this second acceleration, the taxiing became bumpy as the aircraft moved off the central part of the unpaved runway onto a more irregular surface. The instructor attempted to use the control column to realign the aircraft, but the plane failed to respond. The aircraft veered sharply to the right, struck a fence, and came to a stop in an adjacent field. The aircraft sustained damage.
The investigation
The investigation examined the aircraft's mechanical condition and the flight sequence. The instructor noted that the aircraft exhibited unstable yaw movements, which he attributed to a potential shimmy phenomenon. Meteorological conditions were reported as CAVOK with a 5-knot wind aligned with the runway.
Maintenance inspections conducted during repairs revealed some play in certain internal components of the tailwheel, which were subsequently replaced. However, the shock absorber blades and their attachments showed no defects.