Bell 206 N373SP accident near Gonzales, Louisiana

Probable cause

The student pilot’s failure to compensate for an unanticipated right yaw, which resulted in a loss of tail rotor effectiveness and helicopter control.

NTSB analysis

The student pilot entered the traffic pattern for landing at the end of a short cross-country flight in the helicopter. During the downwind leg, he completed the before landing checks and observed no abnormalities with the helicopter.

According to the student pilot, he was on final approach at 40 knots and 175 ft above ground level when the helicopter started to yaw to the right. The student pilot applied left pedal, but the helicopter continued to yaw to the right. The student pilot observed the trim indicator and confirmed that the helicopter was in trim. Shortly thereafter, the helicopter “aggressively” yawed to the right. The student pilot applied forward cyclic input, and the helicopter rolled to the left while it continued to rotate rapidly to the right. The student pilot attempted to regain control using cyclic input; however, he was unable due to the high rotation rate. The student pilot decreased the throttle to idle; the helicopter began to settle; and he applied collective input to cushion the landing. The helicopter landed hard about 200 ft short of the approach end of the runway.

The helicopter sustained substantial damage to the main rotor system, the fuselage, the tail boom, and the tail rotor system. A postaccident examination of the airframe and the engine revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation of the helicopter.

A review of meteorological data at the accident airport showed the wind speed was about 5 knots or less with the direction shifting from a right crosswind to a left crosswind on the landing runway around the time of the accident. It is likely that while on final approach with a low airspeed, the helicopter lost translational lift, which resulted in increased power demand and additional anti-torque requirements. The helicopter began a right yaw and the student pilot allowed a yaw rate to build, at which point he was unable to successfully arrest the yaw rate, and a loss of tail rotor effectiveness and helicopter control occurred.

Text from the NTSB. Open the NTSB docket for CEN22LA009 for the full record.