Freelance writer

Randy Padfield

Two “Fly Neighborly” proponents— Scott Burgess of Embry-Riddle Aeronautical University and David Bjellos, the  aviation manager at Agro Industrial Management—returned at Heli-Expo to reiterate the need for noise abatement and reveal new findings on noise avoidance.

 


Noise produced by helicopters flying overhead continues to become a greater irritant as communities expand and more helicopters take to the air. While noise reduction remains an important goal of rotorcraft manufacturers and there are many cooperative efforts regarding&nbsp;helicopter routing and altitudes, concerns and complaints about helicopter noise continue to increase.

 


Research over the last 12 years—particularly by NASA and the Department of Transportation’s Volpe Center—has revealed useful information about propagation of helicopter noise. In 2011, tests at Eglin AFB of a Bell 430 resulted in rules of thumb for noise abatement. Last year, more extensive tests of six different helicopter models, which collected more than 1,500 data points, put “scientific rigor behind these rules of thumb.”

 


Under the The Rules of Thumb for Flying Neighborly, safe operations remain the priority, and use of noise-reduction techniques should be done without compromising safety. "When noise and safety conflict, safety takes priority," it says.

 


For level flight, the rules of thumb state that accelerations are quieter than decelerations and straight flight is quieter than turns. When turning, Turn away from the advancing blade, especially when decelerating, and level turns are quieter than descending turns. In descending flight, straight-in is quieter than turns and flying the steepest angle practicable helps to reduce the noise footprint. When decelerating, level segment are quieter than approaches and turns. In general, "make smooth control inputs to reduce the noise footprint."

 


The Fly Neighborly/Environmental Committee will be back again at Hel-Expo 2019 with another Fly Neighborly Forum.

News about environmental issues relating to aircraft operations, including noise issues, emissisions, and regulations. See Fuel for biofuel.