page_title: Aircraft noise pollution
section_title: Mechanisms of sound production
hierarchical_section_title: Aircraft noise pollution / Mechanisms of sound production
caption_attribution_description: English: A Grumman American AA-5B Tiger (C-GUDR) lands at La Chute Airport, Quebec, 2004
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: Aircraft noise is noise pollution produced by an aircraft or its components, whether on the ground while parked such as auxiliary power units, while taxiing, on run-up from propeller and jet exhaust, during take off, underneath and lateral to departure and arrival paths, over-flying while en route, or during landing. A moving aircraft including the jet engine or propeller causes compression and rarefaction of the air, producing motion of air molecules. This movement propagates through the air as pressure waves. If these pressure waves are strong enough and within the audible frequency spectrum, a sensation of hearing is produced. Different aircraft types have different noise levels and frequencies. The noise originates from three main sources:
  Engine and other mechanical noise
  Aerodynamic noise
  Noise from aircraft systems
caption: Small general aviation aircraft produce localized aircraft noise.
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