Incident Overview
A flight instructor and a student pilot were conducting training maneuvers in a Schweizer 269C-1 helicopter. The student had just performed a maximum performance departure from a confined area, executing a left turnout and leveling off at 600 feet above ground level (AGL). The instructor then simulated a forced landing condition, prompting the student to enter a 180-degree autorotation to the left.
Autorotation and Descent
During the autorotation, the student maintained good rotor rpm control and a 60-knot airspeed attitude. As the helicopter descended between 150 and 200 feet AGL, the student pulled aft cyclic and raised the collective. This action caused the main rotor rpm to drop rapidly to approximately 380 rpm, and the forward airspeed decreased.
Instructor Intervention and Impact
The instructor responded immediately to the decaying rotor rpm and loss of airspeed. However, the lack of altitude prevented a complete recovery, though the instructor managed to reduce the force of impact. After leveling the aircraft and cushioning the touchdown, the main rotor blades struck a tree, forcing the helicopter onto its right side. One blade then contacted the tail boom.
Engine Shutdown and Evacuation
Following the blade strike, the instructor immediately cut the throttle to the idle position and instructed the student pilot to pull the fuel shutoff valve, shutting down the engine. Both occupants then exited the helicopter. The student pilot sustained minor injuries.
Conclusion
The training flight ended with damage to the helicopter and minor injuries to the student. No further details were provided regarding the cause of the initial low rotor rpm or the sequence of events leading to the tree strike.