Milton Select Board calls for FAA to institute new noise metric; defer pending additional Logan RNAV

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Milton Select Board calls for FAA to institute new noise metric; defer pending additional Logan RNAV

The Milton Select board submitted comments as follows regarding the FAA’s Noise Research Portfolio and Neighborhood Environmental Survey.

To Whom It May Concern:

The Federal Aviation Administration (“FAA”) has invited public comment on the scope and applicability of the research initiatives it sponsors to address civil aircraft noise, which include the Noise Research Portfolio and Neighborhood Environmental Survey (“NES”).

The Town of Milton, Massachusetts, through its Select Board, hereby submits the following comments.


The FAA should use the NES as a basis for policy change because it confirms that DNL is inadequate for overflight noise annoyance measurement. Without policy change, the NES is a moot exercise, and residents under flight paths will continue to suffer. A new noise metric can support flight path reassessment.

The FAA stated its rationale for the NES as follows:

“Aviation noise results in higher annoyance than other modes of transportation. Recent international social surveys have also generally shown higher annoyance than the Schultz Curve. These analyses and survey data indicate that the Schultz Curve may not reflect the current U.S. public perception of aviation noise.” (FAA NES Webinar Announcement).

As the NES shows, it is now inarguable that DNL fails to measure noise annoyance of residents subjected to concentrated RNAV path overflights. Noise annoyance is temporal and spacial, yet DNL mis-measures both aspects because it dilutes measurement of noise annoyance during in-use runway days by inclusion of days not in-use, and it fails to take into account the noise disturbance contribution of peak-time continual short-interval overflight aircraft separation.

No one would measure congestion on a public ski slope by including all days of the year and taking an average of both days in-use and days not in-use. Nor would anyone measure peak-hour highway traffic congestion by ignoring the concentration of vehicles on the roadway and the closer spacing between them at that time and on that narrow set of lanes.

Yet, DNL ignores both of those aspects as applied to RNAV flight paths. It ignores the temporal nature of overflight annoyance and it ignores the increased concentration and compressed repetitiveness of noise disturbance due to sky-rail narrowed paths and reduced 50-second intervals between overflights of the same residents for hours on end. DNL captures none of those specifics. Yet, other metrics have been developed that do so. FAA’s noise measurement policy needs to change now.

DNL should be replaced as the measure of noise annoyance significance by the Nabove 25 flights, 60 dB(day), 50 dB(night) Lmax (peak-day) metric, which is the tool that MIT deemed best for measuring RNAV overflight impacts in its Study. (Data-Driven Flight Procedure Simulation and Noise Analysis in a Large-Scale Air Transportation System, Jensen and Hansman, June 2018 at page 59).


The NES provides further reason that the pending Environmental Assessment of the FAA’s proposed Logan Airport Runway 4L RNAV procedure should be deferred until Order 1050.1f is revised to remove 65 DNL as a noise annoyance significance threshold.

Thank you for your consideration of these comments.

Respectfully submitted:


  • Melinda A. Collins, Chair
  • Kathleen M. Conlon, Vice Chair
  • Arthur Doyle, Secretary
  • Richard G. Wells, Jr.
  • Michael F. Zullas

U.S. Senator Edward J. Markey
U.S. Senator Elizabeth Warren
Representative Stephen F. Lynch
Representative Ayanna Pressley
Attorney General Maura Healey
State Senator Walter F. Timilty
State Representative William Driscoll, Jr.
State Representative Brandi Fluker-Oakley
Milton Community Advisory Committee Representative
Milton Town Counsel

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