Robinson Helicopter Company R44 II N921JM accident near Golden, Colorado

Probable cause

The pilot’s decision to operate the helicopter at a high density altitude near terrain, which resulted in a settling with power condition.

NTSB analysis

The helicopter was following participants in a downhill skateboard race in mountainous terrain. The pilot had just performed a left-pedal turn and the helicopter was facing upslope to the mountain. The low rotor warning sounded and the pilot lowered the collective and increased throttle. The pilot stated that the engine did not respond so he continued to lower the collective and looked for a place to land. During the forced landing on the downsloping terrain the helicopter came to rest on its nose, resulting in substantial damage to the main rotor, skid tubes, and tail boom. Postaccident examination of the helicopter, engine, and systems, revealed no anomalies. The density altitude was calculated to be 10,600 feet. The pilot calculated the in-ground-effect hover to be 8,500 feet pressure altitude, the out-of-ground-effect hover to be 5,000 feet pressure altitude, and estimated the gross weight to be 2,320 pounds.

Text from the NTSB. Open the NTSB docket for CEN11CA325 for the full record.