Helicopter Noise Information for Airports and Communities (2016) / Chapter Skim
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60 APPENDIX C HAI Fly Neighborly Guide
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produced by the Helicopter Association International n Fly Neighborly Committeei Preface This is the third edition of the Helicopter Association International (HAI) Fly Neighborly Guide.
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produced by the Helicopter Association International n Fly Neighborly Committeeii Preface .
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produced by the Helicopter Association International n Fly Neighborly Committeeiii Figure 1 High-Noise Flight Operations – Small/Light Helicopter .
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produced by the Helicopter Association International n Fly Neighborly Committeeiv Foreword In the late 1970s, concern was being expressed about helicopter noise by the general public and national authorities in a number of nations, including the USA. As a result, a number of Helicopter Association International (HAI)
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produced by the Helicopter Association International n Fly Neighborly Committee1 1 General Information 1.1 Background HAI's Heliports and Airways Committee (HAC) originally organized the Fly Neighborly Program through its Fly Neighborly Steering Committee.
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produced by the Helicopter Association International n Fly Neighborly Committee2 flight operations planning. Section Seven deals with community concerns and issues of public acceptance and Section Eight answers the question of what the Fly Neighborly Program can achieve.
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produced by the Helicopter Association International n Fly Neighborly Committee3 2 Helicopter Sound Generation 2.1 The Source of the Sound The external sound produced by a helicopter is made up of acoustical sources from the main rotor, the anti-torque system (tail rotor) , the engine(s)
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produced by the Helicopter Association International n Fly Neighborly Committee4 The Fenestron has some advantages over an open rotor at distance since it generates a higher frequency sound, which is more easily attenuated by the atmosphere. On many helicopters, the main source of noise heard at distance, particularly if a high tip-speed tail rotor is used, is associated with the tail rotor blade thickness.
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produced by the Helicopter Association International n Fly Neighborly Committee5 Figure 1 High-Noise Flight Operations – Small/ Light Helicopter Figure 2 High-Noise Flight Operations – Medium/ Heavy Helicopters Main rotor impulsive noise also occurs during maneuvers (i.e. in constant speed turns, if turn rates are too high.
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produced by the Helicopter Association International n Fly Neighborly Committee6 a two-bladed main rotor, main rotor impulsive noise occurs in turns that exceed 1.5g, with airspeeds between 50 and 90 knots in a left turn, and between 40 and 100 knots in a right turn. There is little difference in the intensity of the noise in right or left turns once the ‘critical g' is reached.
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produced by the Helicopter Association International n Fly Neighborly Committee7 3 General Guidelines for Noise Abatement Operations This section offers a number of noise abatement techniques for use in daily operations. A few general guidelines are given below.
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Figure 4 Fly Higher Chart Safety, Weather or ATC considerations may dictate the need to use alternative heights. 3.2 FAA Guidance - VFR Flight Near Noise Sensitive Areas The FAA has published guidance when flying near noise-sensitive areas for a number of years.
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produced by the Helicopter Association International n Fly Neighborly Committee9 It should be noted that FAA guidance recommends a height of 2,000 ft AGL be used for general over flight of noise-sensitive areas. This is somewhat different than the guidance developed by HAI's Fly Neighborly Committee, discussed previously and illustrated in Figure 4, which recommends 1,000 ft for small helicopters.
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produced by the Helicopter Association International n Fly Neighborly Committee10 4 How to Operate Helicopters Quietly In this section, general information is presented on how to fly a helicopter more quietly. Such information applies to the operation of all helicopters.
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produced by the Helicopter Association International n Fly Neighborly Committee11 n Select a route into the landing area over the least populated area. n Follow major thoroughfares or railway tracks.
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produced by the Helicopter Association International n Fly Neighborly Committee12 Figure 5 Noise Abatement Approach Techniques for Small/Light Helicopters 4.7.2 Medium and heavy helicopters. Follow the noise abatement flight technique given below and illustrated in Figure 6.
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produced by the Helicopter Association International n Fly Neighborly Committee13 Figure 6 Noise Abatement Approach Technique for Medium and Heavy Helicopters The noise abatement flight techniques discussed above for small/light and medium helicopters reduce the ground area exposed to a given noise level by as much as 80 percent. Figure 7 illustrates the potential noise benefits when compared to a normal approach.
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produced by the Helicopter Association International n Fly Neighborly Committee14 4.8 Other Factors to be Considered It is important to mention that the sound environment on the ground and weather have much to do with how offensive helicopter sound is judged. The background noise of residential areas reaches its lowest level between late evening and early morning.
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produced by the Helicopter Association International n Fly Neighborly Committee15 5 Pilot Training The basic scope of the recommended pilot training program and an outline of the requirements for such a program are outlined in this section. The information embodied in other sections of the Guide is also relevant.
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produced by the Helicopter Association International n Fly Neighborly Committee16 6 Operator Program When operating a helicopter in a new area, a new spectrum of sound is added to the usual noise environment. If that area is a municipality, thousands of people will hear the new sounds and know a helicopter is operating.
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produced by the Helicopter Association International n Fly Neighborly Committee17 lines should be used when consistent with prudent and necessary mission requirements. The safe conduct of flight and ground operations remains the primary responsibility.
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produced by the Helicopter Association International n Fly Neighborly Committee18 7 Managing Public Acceptance 7.1 Scope The scope of the public acceptance program includes: n engendering media support n promoting positive public relations n enacting a program to prevent or resolve complaints from the public 7.2 Media Support The purposes of engendering media support are to: n develop favorable and active helicopter-related media coverage n provide valid information concerning helicopter operations as necessary Media sometimes concerned with news of helicopter-related activities include general circulation newspapers, television and radio news, trade journals, and the magazines or newsletters of international, national, state, and regional helicopter associations. To engender awareness and support in these media, a number of actions can be taken: n Provide press releases to trade journals and local newspaper, radio, and television news editors concerning any Fly Neighborly seminars that may be sponsored by the local helicopter operator association.
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produced by the Helicopter Association International n Fly Neighborly Committee19 n local civic and professional organizations such as Rotary or Kiwanis Clubs, the National Association of Aviation Officials, the Airport Operators Council International, or the National Fire Protection Association. Provide speakers for their local meetings.
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produced by the Helicopter Association International n Fly Neighborly Committee20 Figure 8 Relationship between Noise Exposure and Annoyance 7.4.1 Complaint Prevention A significant number of noise-related complaints can be prevented in the first place, given a certain degree of sensitivity, foresight, and commitment. Prevent complaints by assessing the environmental compatibility of potential landing facilities.
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produced by the Helicopter Association International n Fly Neighborly Committee21 or type, it is likely that he or she will be told the aircraft was not in violation of any regulation, and that, therefore, nothing can be done. The result can be an angry, frustrated member of the community who will probably not be particularly supportive of any current or future helicopter or heliport related issue.
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produced by the Helicopter Association International n Fly Neighborly Committee22 8 Fly Neighborly Program– What Can be Achieved? The Fly Neighborly Program outlined in this guide, together with the information on HAI's Noise Abatement Training CD for Pilots, and use of the noise abatement procedures which are available on HAI's Web site, provide the basis for lowering the noise generated by helicopters in day-to-day operations.
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produced by the Helicopter Association International n Fly Neighborly Committee23 Appendix 1 Sound Comparisons The general relationship between sound level and helicopter weight is shown in Figure A1 reproduced from the HAI Helicopter Noise Prediction Method. Smaller helicopters are generally quieter than larger ones and sound levels tend to increase approximately three decibels per doubling of helicopter weight.
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produced by the Helicopter Association International n Fly Neighborly Committee24 What do these sound levels mean? Table A1 provides sound levels for illustrative noise sources heard both outdoors and indoors.
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produced by the Helicopter Association International n Fly Neighborly Committee25 Figure A2 provides some basis for comparing helicopter sound levels to other familiar sounds. Comparisons are made at representative distances from each sound source.
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produced by the Helicopter Association International n Fly Neighborly Committee26 FAA Advisory Circular AC 91.36D Date: September 17, 2004 AC No: 91-36D Subject: VISUAL FLIGHT RULES (VFR) FLIGHT NEAR NOISE-SENSITIVE AREAS Initiated by: ATO-R 1.
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produced by the Helicopter Association International n Fly Neighborly Committee27 Appendix 3 The Portland Public Heliport Noise Abatement Program In 1989, the city of Portland, Oregon and the Northwest Rotorcraft Association decided to build a heliport to provide direct air access to downtown Portland. During hearings to approve the facility, concern was expressed about the resulting noise increase in the area surrounding the heliport.
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produced by the Helicopter Association International n Fly Neighborly Committee28 The acronyms used in this Guide are defined below. AGL Above Ground Level BVI Blade-Vortex Interaction dB Decibels, the basic unit for measuring the level of sounds.
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Fly Neighborly Guide Produced by the Helicopter Association International Fly Neighborly Committee Helicopter Association International 1635 Prince Street Alexandria, VA 22314 USA Phone: (703)
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