EUROCOPTER DEUTSCHLAND GMBH EC135 P1 crash near Chicago, Illinois, United States

The pilot's inadvertent disabling of the No. 1 and No. 2 engines' electronic engine control systems, which resulted in engine and rotor overspeed conditions, a subsequent autorotation, and a hard landing. Contributing to the accident were the pilot's inexperience with the helicopter variant and the operator’s lack of a more robust helicopter differences training program.