Radio frequency interference from nearby high-powered transmission broadcast towers resulted in what the pilot described as an uncommanded decrease in engine power and contributed to the June 24, 2014, hard landing of a Robinson R44 II, the U.S. National Transportation Safety Board (NTSB) says.1
Robinson Helicopter had warned of the problem in a 1999 safety notice,2 issued after several accidents that also occurred in close proximity to high-intensity broadcast towers, the NTSB said.
In its final report on the accident, released in mid-August, the NTSB said that the probable cause was “the pilot’s failure to maintain rotor rpm during an autorotation after a perceived partial loss of power, which resulted in a hard landing.” Radio frequency interference with the helicopter’s governor controller was a contributing factor, the agency said, noting that the interference “resulted in an uncommanded decrease in throttle and the perceived loss of engine powe…
