Training Scenario
A flight instructor was providing instruction to a new-hire pilot preparing for a 14 CFR Part 135 check ride. A second new-hire pilot occupied the rear seat to observe the training session. The pilot trainee was practicing a hydraulics-off, run-on landing.
Incident Sequence
As the student approached the touchdown point, the instructor reminded him to maintain airspeed. The instructor reported that just before touchdown, the helicopter's controls became very stiff. The flight instructor then directed the trainee to re-engage the hydraulics isolation switch on the collective control. The student complied, but reported that the controls remained stiff and he experienced difficulty applying forward cyclic. When the instructor took over the controls, the helicopter initiated a slow left turn. Despite the instructor's attempts to counteract the turn, the rate of turn increased. The helicopter subsequently struck the ground while in a left turn with rear lateral movement. The impact caused the landing gear skids to collapse.