Robinson R44 N728CB accident near Newton, North Carolina

Probable cause

The pilot's failure to maintain an adequate airspeed during out-of-ground-effect maneuvering at a low airspeed with a tailwind, which resulted in a loss of helicopter control due to a loss of tail rotor effectiveness.

NTSB analysis

The commercial helicopter pilot and a crewmember were conducting a pipeline patrol when they noticed a right-of-way infraction (construction work) that they wanted to photograph. The pilot then entered a left circuit at 500 ft above ground level. The pilot reported that he subsequently felt a shudder in the controls and that the helicopter began to yaw right and spin. Although the pilot reported that he maintained an airspeed of 70 knots while maneuvering, GPS data revealed that the loss of yaw control occurred at the completion of the first left circuit and the beginning of the second left circuit as the helicopter slowed to a groundspeed of about 1 mph. Weather data indicated that, at this point, the helicopter was experiencing an 8-knot tailwind. The pilot lowered the helicopter's nose but was unable to correct the spin. He entered an autorotation and maneuvered to avoid residences and utility poles, and the helicopter then impacted the ground.

Examination of the helicopter did not reveal any evidence of preimpact mechanical malfunctions that would have precluded normal operation. It is likely that the low-airspeed condition combined with a tailwind during out-of-ground-effect maneuvering resulted in a loss of helicopter control due to a loss of tail rotor effectiveness.

Text from the NTSB. Open the NTSB docket for ERA17LA168 for the full record.