20220930011209A

A CFI and student pilot were performing an off-field landing. As they were approaching the landing spot the CFI had the student practicing orbits. A high reconnaissance orbit was performed at 500 feet AGL and a low reconnaissance orbit at 300 feet AGL. They briefed approach and then circled around and set up for a power check and low pass. The CFI stated the first power check was done facing the wind (which was coming from the north around 350-010 magnetic at about 10-15KTS) and came to a stop at about 17-18” manifold pressure. He stated this was low considering they were in a hover. They descended to 300’AGL for a last low pass and circled around at 300’AGL to get aligned. They came into the off-airport landing area from south to north with a headwind. The CFI stated they did one last power check close to the ground. Last reported power check was 20” of manifold at approximately 10-15’ hover and 30-50’ south of the spot over a dirt road. The area was confined with Cedar trees and a rock pit in the middle. The student said he didn’t want to touch the skids with the slope so the CFI had him come to a 5-7’ hover. They reported 20.8” on the manifold gage. On departure there were trees at nose height in front of the aircraft. The student began to add power, the full throttle light came on at 22.5” of manifold pressure. The CFI said he immediately lowered the collective to extinguish the light. The aircraft was now in a 3- 5’ hover the CFI reported concern about the tail of the aircraft since there were trees and fence post behind them. The CFI asked the student to come back to a 5’ hover, taxi a bit forward to clear the tail for a pedal turn and to put the nose of the helicopter facing slightly more northeast for the departure. The carburetor heat was brought in approximately one quarter for the departure. As the cyclic was being pushed forward there was a jolt in the helicopter and a left yaw. The CFI immediately took the controls. The helicopter was gaining speed and altitude in the departure. The area was too confined to come to a stop. The CFI continued forward on the cyclic. The helicopter started to vibrate and they experienced another “major” left yaw. The engine RPM began to fall rapidly and the aircraft began to fall. The engine tachometer was falling more rapidly than the rotor tach. The CFI lowered collective and rolled in throttle the engine RPM still was falling rapidly. During the loss of engine RPM, the rotor RPM experienced a loss as well and the low rotor RPM horn came on. The engine RPM was reported at approximately 80%. The CFI knew at this point they were committed to landing. They experienced a left yaw each time they felt the aircraft jolt. The CFI reported using right pedal to counteract the yaw. The CFI began a flare and leveled off in an attempt to align it with the steeper slope. The helicopter made contact with the trees. The CFI reported he “came hard aft to stop the aircraft from moving anymore forward which would have caused us to roll. In the process, I cut the tail off with the main rotor blade.”

An ASI (maintenance) from the slc FSDO and a mechanic from suu inspected the aircraft after it was transported from the sight to a maintence hanger. They followed the manufactures check list and did not find any power loss indications.