Regulations specifying what airports can and cannot do for noise abatement are contained in the F.A.R. Part 150 & F.A.R. Part 161. Airports wishing to institute noise new noise regulations are governed by the Airport Noise and Capacity Act of 1990 (ANCA).
In the years since the passage of ANCA and F.A.R. Part 161, very few airports have attempted the F.A.R. Part 161 study process to implement restrictions on aircraft. The city of Scottsdale evaluated this process and determined it was not feasible.
Federal Aviation Regulation Part 36 outlines how much noise aircraft can emit during different phases of flight. Since the 1960s when jet aircraft became more common, a cornerstone of the Federal noise policy is the reduction of aircraft noise through the development of quieter engines. Aircraft are classified in different noise categories called: Stage 1, 2 or 3. Stage 1 is considered the noisiest and Stage 4 the quietest. Most of the aircraft fleet operating at Scottsdale Airport are Stage 3. A common misconception is that a larger aircraft is noisier and that's not always the case. Commercial jets, even larger ones, produced currently are quieter now than in the past.
However while noise emissions have decreased, the volume of aircraft traffic has increased. This "trade off" often results in a public perception of increased noise impacts.
The FAA on November 3, 2017, adopted the Stage 5 Noise Standard for newly manufactured aircraft. The FAA’s Stage 5 Noise Standard is equivalent to the International Civil Aviation Organization (ICAO) Chapter 14 of Annex 16, Volume I. Stage 5 is an overall 7-dB noise reduction from the previous Stage 4 Noise Standard and requires at least a 1-dB noise reduction from Stage 3 Noise Standard at every aircraft noise certification point, which includes arrival, departure and sideline. Stage 5 standard applies to aircraft takeoff weights of 121,254 pounds or greater December 31, 2017, and to aircraft takeoff weights less than 121,254 pounds December 31, 2020.
Federal law has established the Day-Night Level (DNL) metric as the standard for measuring aircraft noise. The DNL metric was established by the Federal Interagency Committee on Aviation Noise (FICAN) and is the method used in the 14 CFR Part 150 Airport Noise and Land Use Compatibility Study process to measure aircraft noise impacts. The DNL metric measures average sound over a 24-hour period.
More information on the measurement of aircraft noise is contained in Technical Information Paper - "The Measurement & Analysis of Sound".
