The helicopter was being used for dual flight instruction of several students. The instructor pilot (IP) stated that he held the controls while his second student exited and the third student got in and adjusted his seat and pedals. After performing the before takeoff checks, the student pilot began to bring the helicopter to a hover. As the student began to hover, the IP looked to the left in the direction that they intended to hover. He stated that before he completed the clearing glance, he felt the helicopter pitch forward and to the right. Subsequently, the forward part of the right skid hit the ground and the helicopter went out of control. The IP stated that he took control and felt extreme right/forward pressure on the cyclic, the right pedal felt stuck, and the collective had an extreme downward pressure. During the investigation, the 3 main hydraulic servos and tail rotor servo were found operational. No evidence of a preimpact structural failure was found.