Amateur-built ROTORWAY EXEC 162F N162RB accident near Seadrift, Texas

Probable cause

A fault in the No. 1 engine control module, which disabled the ignition system and resulted in the engine losing power; during the subsequent autorotation, the main rotor rpm was further reduced just before touchdown, which resulted in a hard landing.

NTSB analysis

The pilot reported that the experimental, amateur-built helicopter was at 300 ft above ground level (agl) when the low rotor rpm horn sounded and the engine lost power. The pilot entered an autorotation and arrested the descent rate. When the helicopter was about 8 ft agl over tall grass, the main rotor speed further decelerated. The helicopter landed hard while it was still moving forward at high speed, which resulted in the landing gear separating.

The engine had been modified with a full authority digital electronic control (FADEC) system. Following the accident, the pilot tested the FADEC system and determined that the loss of engine power was caused by a fault in the No. 1 engine control module (ECM); every time the No. 1 ECM was turned on, the engine would quit; however, if the No. 1 ECM was turned off and the No. 2 ECM was turned on, the engine would operate. Although the helicopter was equipped with two ECMs, which should have provided redundant operation, it was determined that a single-point failure of the No. 1 ECM resulted in the engine failure.

Text from the NTSB. Open the NTSB docket for CEN15LA132 for the full record.