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Short answer: Aircraft noise is the sound produced by aircraft engines, airframes and propellers or rotors during takeoff, flight and landing. It is managed in two separate ways: ICAO certifies each aircraft type against noise limits at design stage (Annex 16, Volume I), and airport-area exposure is assessed with a yearly day-night average sound level (DNL), which US land-use guidance under 14 CFR Part 150 compares against a 65 dB line.
Definition and scope
Aircraft noise covers sound from jet and large propeller aeroplanes, light propeller aeroplanes, helicopters, tiltrotors and supersonic aircraft. ICAO describes noise as controlled through Standards and Recommended Practices (SARPs) since the 1970s, collected in Annex 16, Volume I, and says certification ensures the latest noise-reduction technology is incorporated into aircraft design. Reduction of noise at source is, in ICAO’s words, an important pillar of the Balanced Approach to Aircraft Noise Management.
Two questions are easy to confuse. How loud is this aircraft type when certified? is answered by certification. How much noise do people near an airport receive over a year? is answered by cumulative exposure metrics such as DNL. They use different measurements for different purposes.
How noise is certified: ICAO Annex 16, Volume I
Chapter 2, the first standard for jet and large propeller aeroplanes, applied from 1972. It set three reference measurement points and limits that scale with maximum take-off mass. Later chapters tightened the limits as technology changed.
| Annex 16 Vol. I chapter | Adopted or applicable | What changed |
|---|---|---|
| Chapter 2 | Applicable from 1972 | First jet and large propeller standards; three reference points; limits by maximum take-off mass |
| Chapter 3 | 1977 | More stringent than Chapter 2, after high-bypass engines |
| Chapter 4 | After Chapter 3 | Further tightening |
| Chapter 14 | Adopted 2014 (CAEP/9 recommendation, February 2013) | 7 EPNdB cumulative more stringent than Chapter 4; new types from 31 December 2017, and from 31 December 2020 for aircraft under 55 tonnes |
| Chapter 16 | Adopted 27 March 2026 | 6 dB more stringent for large aircraft and 2 dB for smaller ones; new type designs from 2029 |
Other aircraft classes have their own chapters: light propeller aeroplanes (Chapter 10, from 1974, up to 8,618 kg, measured at one point 2,500 m from the start of the take-off roll), helicopters (from 1981, with a simplified Chapter 11 procedure up to 3,175 kg), and tiltrotors (Chapter 13, 2014). For supersonic aircraft, limits adopted in March 2026 and applicable from 2029 must be as stringent as Chapter 14, replacing Chapter 12. ICAO expects Chapter 16 to remove more than one million people from DNL 55 dB affected areas over 2032-2048.
How community exposure is measured: DNL and 14 CFR Part 150
Appendix A of 14 CFR Part 150 requires the yearly day-night average sound level (YDNL) for cumulative noise exposure around airports, with contours developed for 65, 70 and 75 dB. It states that all land uses are considered compatible with noise levels below Ldn 65 dB.
Land-use compatibility at a glance
| Land use (Part 150, Appendix A, Table 1) | At 65-70 dB DNL |
|---|---|
| Residential and schools | Generally not compatible, unless the community determines such uses must be allowed |
| Hospitals and nursing homes | Generally compatible if noise level reduction of 25, 30 or 35 dB is incorporated into the building |
For labs and clinics near an airport, this is the sourced reference point: the compatibility table treats hospitals as acceptable at 65-70 dB only with building noise reduction, while schools and homes are generally not compatible at that level. Part 150 does not itself set rules for vibration-sensitive instruments; any such requirement comes from the equipment maker or the facility design brief. See laboratory construction for facility planning context.
Common misunderstandings
- A certification level is not a neighbourhood noise level. Certification is measured at defined reference points for an aircraft type; DNL is a yearly average over all operations at a location.
- Newer chapters apply to new type designs. Chapter 14 and Chapter 16 apply by type-design date, as stated in the table above, not retroactively to every aircraft in service.
- 65 dB is a planning threshold, not a health limit. In Part 150 it is the line below which all land uses are considered compatible.
- Hearing protection ratings are a different system. Occupational ratings such as those in noise reduction rating (NRR) for earplugs describe protector attenuation, not aircraft exposure.
FAQ
What is aircraft noise?
Sound generated by aircraft in operation, regulated at the aircraft level through ICAO Annex 16, Volume I certification and assessed around airports with cumulative metrics such as DNL.
Who sets aircraft noise certification limits?
ICAO sets the international standards in Annex 16, Volume I; the most recent, Chapter 16, was adopted on 27 March 2026.
What does 65 dB DNL mean?
In 14 CFR Part 150 Appendix A, it is the level below which all land uses are considered compatible, and the lowest contour that must be developed.
Where can I learn about related measurement and facilities topics?
See audiometric booths for controlled-noise test environments and environmental health for the wider field.
Sources
- ICAO, Reduction of Noise at Source: icao.int/environmental-protection/Pages/Reduction-of-Noise-at-Source.aspx (read 2026-11-08).
- 14 CFR Part 150, Appendix A (eCFR): ecfr.gov/current/title-14/part-150 (read 2026-11-08).
