page_title: Aircraft noise pollution
section_title: Regulation
hierarchical_section_title: Aircraft noise pollution / Mitigation programs / Regulation
caption_attribution_description: English: FAA noise stage 2 for helicopters: approach (p. 357)
context_page_description: Aircraft noise pollution is a harmful noise effect produced by aircraft in flight. Sound production is divided into three categories:
  Mechanical noise—rotation of the engine parts, most noticeable when fan blades reach supersonic speeds.
  Aerodynamic noise—from the airflow around the surfaces of the aircraft, especially when flying low at high speeds.
  Noise from aircraft systems—cockpit and cabin pressurization and conditioning systems, and Auxiliary Power units.
  Health consequences include sleep disturbance, hearing impairment and heart disease, as well as workplace accidents caused by stress. Memory and recall can also be affected. Governments have enacted extensive controls that apply to aircraft designers, manufacturers, and operators, resulting in improved procedures and cuts in pollution.
context_section_description: Stages are defined in the US Code of Federal Regulations (CFR) Title 14 Part 36.
  For civil jet aircraft, the US FAA Stage 1 is the loudest and Stage 4 is quieter.
  Stage 3 was required for all large jet and turboprop aircraft at US civilian airports from the year 2000,
  and at least Stage 2 for under 75,000 lb (34 t) MTOW jets until December 31, 2015.
  The current is Stage 4 for large airplanes, equivalent to the ICAO Annex 16, Volume 1 Chapter 4 standards, while the more stringent Chapter 14 became effective July 14, 2014, and is adopted by the FAA as Stage 5 from January 14, 2016, effective for new type certificates from December 31, 2017 or December 31, 2020 depending on weight.
  The US allows both the louder Stage 1 and quiet Stage 2 helicopters.
  The quietest Stage 3 helicopter noise standard became effective on May 5, 2014, and are consistent with ICAO Chapter 8 and Chapter 11.
caption: Helicopters stage 2 Noise standard: approach
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