Robinson Helicopter R22 BETA N112HE accident near Bulverde, Texas

Probable cause

The in-flight separation of the fuel cap, which impacted the helicopter’s tail rotor and resulted in the loss of tail rotor thrust. Contributing to the accident was the inadequate preflight inspection by both pilots, who did not ensure that the fuel cap was securely tightened before flight.

NTSB analysis

Prior to the flight, the flight instructor refueled the helicopter, and the student pilot performed a pre-flight inspection of the helicopter. The instructor and student then departed and were practicing autorotations when the helicopter yawed left and right. The instructor initiated an autorotation to an orchard. The helicopter impacted the ground and trees before coming to rest on its left side. Examination of the wreckage revealed that the left fuel tank’s gas cap was missing. A search in the direction of the helicopter’s flight path located a piece of tail rotor blade and the fuel cap, which had separated into two pieces. Additionally, the fuel cap’s gasket was missing. It could not be determined if the gasket was on the fuel cap before the cap separated from the helicopter. The impact marks on the fuel cap and tail rotor blade piece were consistent with the fuel cap coming into contact with the tail rotor blade.

Text from the NTSB. Open the NTSB docket for CEN11LA226 for the full record.