Date: 201305
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Landing
ATC / advisory: CTAF ZZZ
Reporter organization: Personal
Reporter function: Pilot Not Flying; Trainee
Reporter qualification: Flight Crew Instrument; Flight Crew Commercial
Human factors: Human-Machine Interface
Second reporter function: Instructor; Pilot Flying
Anomaly: Ground Excursion Runway; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged; Flight Crew Regained Aircraft Control
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: During initial tailwheel instruction in Stinson 108; we were on our third and final landing of the day. My instructor instructed me to land the aircraft. On the rollout the tail began to swerve; so the instructor said; 'my airplane' and took the controls. I immediately said; 'your airplane' and gave control to the instructor. He initially corrected and started to slow the airplane; but then there was a hard swerve to the right; the tail came around and the plane traveled towards the runway edge. The right landing gear left the runway; and as the instructor turned the plane back onto the asphalt; I heard the prop strike and said 'I think we had a prop strike'; he replied 'yes; I think so.' he later said his foot had slipped off the rudder pedal; causing the hard swerve to the right. He got the plane stopped and we taxied back to the hangar. The engine sounded fine; and we confirmed upon shutdown that the propeller edges had been bent. The only damage to the plane appears to be the prop strike. The instructor later said he thought the problem was very avoidable and that he felt responsible due to the foot slip. I believe the problem was caused primarily by instructor's unfamiliarity with the aircraft; as he said the rudder pedals are in a different place in his airplane; so that when he corrected with the rudder his foot slipped. He also remarked how the rudder handled differently than in his aircraft. Also; I am not signed off in the plane which is why I was getting the instruction. Continued training; and/or sticking with tricycle gear aircraft can prevent a recurrence of this event.


Second narrative: Flying a 1946 Stinson; new to both student and instructor.  Practice takeoffs and landings.  Students landing had a directional control problem.  I took the controls; in doing so the aircraft ground looped.  The prop struck the ground; no other damage to the aircraft.  As an instructor I have several hundred hours in Citabrias.  I think the position of the rudder pedals in the Stinson; very close together with structural members next to them might have been a factor.  The Citabrias are spaced much farther apart.  I feel the position of my feet was slightly off; perhaps the half second it took to reposition them was a factor in the incident.  Being new to the Stinson I should have taken note of the unique nature of the Stinson cockpit.


Synopsis: Stinson 108 student pilot reports swerving during his third landing and having the instructor take control. The instructor initially corrects then ground loops the aircraft causing a runway excursion and propeller damage.