Robinson Helicopter R22 Beta II N588LE accident near Encinitas, California

Probable cause

A partial loss of engine power for an undetermined reason. Contributing to the accident was the soft terrain.

NTSB analysis

The pilot, who also operated the flight school that owned the helicopter, reported that he was giving a prospective flight instructor a pre-employment check ride. The flight instructor entered a practice autorotation from approximately 700 to 800 feet mean sea level to the beach at the ocean shoreline with the plan to perform a power recovery. When the flight instructor attempted to increase power, the power recovered to only approximately 70 percent. The pilot took the flight controls and performed an emergency autorotation to the sandy beach. The helicopter's forward motion was between 3 to 5 knots when it touched down. The pilot said the helicopter stopped suddenly due to the wet sand, causing the aircraft to rock forward and back. The backward motion permitted a main rotor blade to slice through and separate the tail boom. A post accident engine run was performed with no operational difficulties noted.

Text from the NTSB. Open the NTSB docket for WPR09CA118 for the full record.