Robinson R22 Beta II N926EL accident near Flagstaff, Arizona

Probable cause

The pilot's decision to attempt a takeoff in a high density altitude high gross weight condition that exceeded the takeoff performance capability of the helicopter. The pilot's failure to maintain adequate rotor rpm was also causal. Contributing factors were the high density altitude and the uneven high elevation terrain.

NTSB analysis

The pilot reported that due to the density altitude and the weight of the helicopter, he could not gain sufficient airspeed during the takeoff to climb. As the helicopter approached a tree line he initiated a left turn to avoid the trees after receiving a "low rotor" rpm warning. The pilot lowered collective and added throttle just before impacting rough, uneven terrain, which resulted in substantial damage to the helicopter. The pilot stated, "…it [the helicopter] was just too heavy and it was too hot, and the terrain was not level for a run on landing." The density altitude at the time of the accident was calculated to be 10,612 feet.

Text from the NTSB. Open the NTSB docket for SEA08CA208 for the full record.