At the October 2019 HFAC meeting, Bedford resident Patty Dahlgren brought to Commission members’ attention an airfield noise issue that came up during the series of meetings Massport held last June to present its latest Environmental Status and Planning Report for Hanscom Field to the public. Dahlgren said residents had been shocked to learn that Massport uses a model to predict the impact of aircraft noise on nearby neighborhoods that excludes all ground noise generated by aircraft operations.
After describing the “picture frame on the wall-shaking volume” from jets sitting on the runway that residents near her side of the airfield often hear and feel, Dahlgren went on: “So much of the noise that local residents experience is what happens when [the aircraft] are sitting on that runway. And it’s not always 30 seconds worth of time either. It’s a significant amount of time, far more significant, in fact, than the amount of time it takes to leave our neighborhood. We might be talking 10, 15 minutes out there.
“So I’m trying to understand the rationale of a model not incorporating what, at least to the local residents feels like, in many ways, the largest, strongest, most intimidating aspect of that sound,” Dahlgren continued. “I tell people that it’s not measured until the wheels leave Massport’s ground and everyone looks at me like I’m crazy.
“What about that process? How is that not part of operations,” she concluded.
Amber Goodspeed, Airport Administrative Manager, replied that the Massport noise model meets national standards. Thomas Hirsch, a Commission member and Hanscom Pilots Association representative, then explained the model has been around for a long time and is based purely on counts of take-offs and landings by aircraft type.
Conjecturing that the original goal of the creators may have been for the model to apply to every airport, HFAC Chair Christopher Eliot of Lincoln suggested, “Because airports are configured differently, all of that ground noise would not be something they could build a scientifically reproducible model for.”
“It’s still noise,” Dahlgren protested. “It’s still noise that we apparently have no metrics for.”
“It’s one of the limitations of attempting to build a scientific predictive tool,” Eliot noted, adding later, “What it is not, is customized for the airport. It’s a general-purpose model.”
When Eliot observed there is room for improvement in the model, Hirsch added that would mean additional data would have to be collected. Eliot agreed with him, pointing out that data collection is expensive. Hirsch summed the problem up, “Counts are easy, anything else is really difficult.”
Dahlgren persisted, “Collecting the data is expensive, but so is living next to an airport where the majority of the sound that we suffer from can’t be measured because of an antiquated model. I just want to state that for the record. And it sounds like there’s a tremendous opportunity here in this age of AI and metrics to address where the real sound is coming from, as opposed to the minute or the 30 seconds when the plane shoots over our heads.”
Hirsch asked, “What do you expect can be done? Even if you had different numbers? What would this lead to? What is the net effect? How do we fix anything just because we know these numbers?”
After further discussion, Eliot observed, “The lack of knowledge of the solution doesn’t mean that a solution couldn’t be found.” Noting that HFAC alone cannot provide a solution, he said, “I think these things end up being national issues,” adding that better information going to politicians might help raise their awareness of the situation.
Kati Winchell, a representative of Save Our Heritage (a Concord-based nonprofit organization devoted to protecting historic, cultural and environmental resources of Concord, Bedford, Lincoln and Lexington from degradation by pollution, noise, and development) reminded Commission members that HFAC has in the past often brought issues of concern to the attention of politicians.
Note: The noise model discussed here was used by Massport in its latest Environmental Status and Planning Report for Hanscom Field to predict there will be no noise impact on local residents from its large planned corporate hangar and T-hangar developments (with a combined footprint of up to 165,000 square feet) along Hartwell Road across from The Edge Sports Center. See: https://www.thebedfordcitizen.org/2019/07/topics-of-potential-concern-to-bedford-in-massports-recently-released-2017-environmental-status-and-planning-report-espr-for-hanscom-field/