Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 130; Flight Crew Total 389; Flight Crew Type 121
Situational Awareness; Training / Qualification
Ground Event / Encounter Loss Of Aircraft Control; Ground Excursion Runway
Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Human Factors
After a stabilized approach to land on runway XXL; we touched down in a normal attitude. Immediately afterwards; the airplane suddenly started to veer to the right. I called for the flight controls; but it appeared the student had locked his legs and was pressing hard on the right rudder. I called for the controls again while applying left rudder in an attempt to stay on the runway; but was unable to overcome the student's rudder pressure. To get the student to release the rudder pressure; I slapped the student's leg and yelled 'move your feet off the pedals; my controls'; but by that time; we went into the grass near the taxiway[s]. We did not hit any runway lights or other signage; and were carried onto the pavement of [taxiway] by our momentum. Only then did we manage to stop the airplane. Tower called FBO1 and a car with Maintenance personnel came out to assist us; and we shut down the aircraft. Upon inspection; we did not find any apparent evidence of damage to the airframe. We decided to taxi back to [FBO2]. Our mechanics were notified; and the airplane was immediately grounded. We spoke to ZZZ Tower upon their request; and all they wanted was a description of what happened; and to make sure that everyone was okay. I gave them my information and statement; and they did not request any further action. The only thing I might have done differently is have FBO1 tow the airplane back to our ramp; just in case of internal damage to the plane. This was out of my control because the student did not let go of the rudder. Whenever I debriefed with the student; I asked why did he not let the control go and the student replied that he just froze and blacked out and that is what caused him to lock his foot down on the rudder.
Instructor pilot reported student locked up the rudder with his legs causing the aircraft to leave the runway after landing.