Low Overhead, High Impact: Airplane noise has Greater Boston up in arms

Wherever you travel around the world, chances are that pretty much every major city has a group of residents who have qualms with airplane noise. From London and the Cranford Agreement to the LaGuardia curfew in New York, airports, airlines, and pilots are forced to abide by certain rules in order to mitigate the inevitable noise that’s generated by aircraft.

Here in Boston, we’re not immune to these problems. As the 51st-largest airport in the world based on passenger traffic, Boston Logan International Airport sees a significant number of planes land and take off every day, many of which generate lots of noise. And while the implementation of RNAV (GPS) procedures from Runway 33L in 2013 as part of the FAA’s NextGen program has decreased the noise impact for a number of residents, it has conversely increased noise for others. As a result, there’s been palpable unrest in some of the impacted communities in the past few years.

The Basics

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A basic overview of Logan Airport.

As you can see from the graphic above, Logan has six runways:

  • Runway 15R/33L (10,083 feet)
  • Runway 4R/22L (10,006 feet)
  • Runway 4L/22R (7,864 feet)
  • Runway 9/27 (7,000 feet)
  • Runway 14/32 (5,000 feet)
  • Runway 15L/33R (2,557 feet)

Each runway is numbered by its magnetic heading. As you can tell, 4L/22R and 4R/22L run southwest to northeast, 9/27 runs east to west, and 14/32, 15L/33R, and 15R/33L run southeast to northwest.

Depending on which way the wind is blowing, the airport uses two (or more) runways at any given time. Each of the wind’s four intercardinal directions possesses its own configuration, each of which is illustrated below:

One minor qualm: the “Southeast configuration” doesn’t really exist as it is presented; it is extremely rare for arrivals to land 15R, as the ILS approach has an offset localizer. In that case, arrivals (interestingly enough) go to 4R.

What was it like before?

Prior to the implementation of 33L RNAV procedures, pilots used to simply fly generally along a given path. For example, a pilot who flew two 33L departures in a given month might make a left turn 30 seconds after rotation one time and a minute after rotation another time, which resulted in an extensive amount of variability in where the low-flying airplanes would be going. With RNAV, however, pilots are given a prescribed course of waypoints, often part of a SID (Standard Instrument Departure). These courses can even be flown by the plane’s autopilot, resulting in a route that’s much more precise than if it was simply “eyeballed.”

Generally speaking, a lot of communities west of Boston were forced to endure airplane noise, but such instances of noisy takeoffs were spread out. Below is an image that depicts the flight paths out of Logan before (green) and after (blue) RNAV implementation.

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As you can tell, flights have been much more specific in their routing since the implementation of 33L RNAV procedures.

Post-RNAV implementation has seen reductions in the number of communities impacted. However, the communities under RNAV patterns – particularly communities within the Route 128/I-95 belt – have seen a dramatic increase in overflights.

From Summer 2014 to Spring 2016, I lived in Somerville, quite close to waypoint TEKKK – the first GPS waypoint that planes departing from 33L must pass. As such, I got to watch an extensive number of aircraft from my bedroom window, flying a variety of routes, including the CELTK and LBSTA departures which are used by planes departing for Europe. And while I ultimately enjoyed seeing pretty much every heavy that went by, my favorite was undoubtedly the British Airways Boeing 747-400, which you’ll know if you read this blog regularly. Below, two pictures of that exact plane, taken from my living room:

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The Union Jack turning left at TEKKK after takeoff from 33L.
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Even caught a rare 15R arrival!

As you can tell from those pictures, those 747s were low – around 2,500 feet on departure and 1,500 feet on arrival. While I personally was thrilled to live in such an area, I know for a fact that many of my neighbors were not happy with the amount of air traffic coming over their heads. Even as an aviation enthusiast, I can understand why.

So who bears the brunt of the noise?

There is no foolproof way to know who in particular is impacted by airplane noise, or how much the total impact is (in terms of quality of life, decibels, etc.), so the best general metric I could devise was to aggregate the populations of all of the municipalities impacted by a given configuration.

As it is, the Northwest configuration – the one that uses 33L and 27 – has the largest impact on residents of the Greater Boston area. Due to the westerly direction of both runways, and the fact that Boston and most of its suburbs are located west of the airport, its SID patterns see aircraft of all sizes flying around or below 5,000 feet pass over a number of densely-populated communities, including Boston, Chelsea, Everett, Winchester, Medford, Somerville, Cambridge, Belmont, Watertown, Newton, Brookline, Quincy, and Milton. That’s not even including places like Waltham, which are further from the airport but where aircraft may well be below 5,000 feet depending on climb rates/etc. Even so, the total population of the area impacted by Northwest arrivals and departures is 1.503 million, or 22% of the Commonwealth’s population.

For perspective, the next closest operational configuration in terms of population impacted is the Southeast configuration, which sees aircraft take off and land over towns with a total population of 929,200, with the Northeast configuration affecting 886,000 people and the Southwest configuration impacting 884,900. Of course, all of those numbers factor in Boston’s 645,900 people, as each configuration has an impact on Boston proper, but the Northwest configuration sends by far the largest number of planes over Boston – particularly departures from 27. Moreover, even if we were to take out Boston’s population from each of those figures, the Northwest configuration would still have the largest number of residents impacted by a considerable amount.

If we want to consider solely departures as having a significant impact on residents by subtracting the municipalities over which solely see arrivals in a given configuration from the total, then the Northwest configuration still affects 1.475 million people. The remaining three, meanwhile, affect less than 50% of that number: the Southwest 737,100, the Northeast 718,400, and the Southeast 673,500. The reason that the latter three numbers are so low is because their departure procedures by and large send aircraft over water upon takeoff: even the southwest departures make an immediate left turn out to sea after takeoff from 22L or 22R, and 27 departures are virtually never used in the Southwest configuration. Northwest departures, meanwhile, are almost entirely over land for the first 5,000 feet.

Even so, it hasn’t just been the towns impacted by 33L departures who have felt aggrieved. Milton, which finds itself situated under the 4L visual and 4R ILS approaches, sees a number of aircraft, including 33L departures, albeit at a higher altitude than places like Belmont, Cambridge, Medford, and Somerville. And though – all things equal – the noise of a landing plane isn’t the same as one that’s taking off, Milton residents do have legitimate reasons to be concerned, as Milton selectmen have requested a study to evaluate the health impact of having so many planes flying low.

If RNAV increases concentration over certain neighborhoods, why implement it?

It’s the best solution for the majority of parties involved: pilots, passengers, and people on the ground.

Quite frankly, you can’t please everybody. Certainly, those living directly under these flight paths are much more heavily impacted than those who do not. However, as this Boston Globe article explains, RNAV procedures are designed to – among other things – increase safety and improve operational efficiency.

RNAV isn’t just beneficial for planes taking off; it also provides pilots with the ability to make smoother, more efficient descents. And while RNAV also has an impact on places over which planes are landing, logic suggests that, at least as far as sound is concerned, departures have a greater impact on residents than arrivals. This is because aircraft need significantly more power – which generates noise – to take off than they do to land. When a plane is taking off, it’s much heavier than it is when it’s landing, as it’s full of fuel. Moreover, the plane is forced to accelerate from a standstill to its takeoff speed, which can be up to 160 mph in the case of a 747. The principles behind landing, meanwhile, are just the opposite: a plane sheds speed – using minimal power – and comes in for a landing at a lighter weight and slower speed than it took off at. All other things equal, landings generate much less noise than takeoffs.

While this is an aviation blog, I certainly do sympathize with those who have to live in a location where airplane noise is consistent. However, until planes have the capability to fly without generating any engine noise, this will ultimately be an issue we’ll have to deal with.

The Numbers

It’s not all doom and gloom, however. According to this Massport table, numbers have shown that the distribution of flow configuration utilization is fairly equitable.

As far as jet departures are concerned, the 2016 YTD (January to September) numbers look like this:

  • Northwest configuration – 25.9%
  • Northeast configuration – 20.7%
  • Southwest configuration – 30.9%
  • Southeast configuration – 22.4%

Since Runway 9 is part of both the Northeast and Southeast configurations, its total number of departures have been split 50-50 between the total for each configuration for the purposes of this analysis. Of course, such a distribution is extremely unlikely, but I don’t have the resources to go back and analyze which Runway 9 departures were operations as part of which configuration, so I figured that was the most equitable way to do it.

Moreover, Northwest winds tend to increase in the late fall and winter, so perhaps the numbers don’t yet tell the full story. With that in mind, here’s the 2015 data:

  • Northwest configuration – 27.5%
  • Northeast configuration – 18.8%
  • Southwest configuration – 34.7%
  • Southeast configuration – 19.0%

Even the most-used runway – Runway 9 – which is part of both the Northeast and Southeast configurations has been used less than 1/3 of the time, at 32.5%. I’m certainly not trying to minimize the impact that Winthrop residents feel when planes take off or land on 9/27, as they are generally very low in both instances, but I don’t have the power to provide an immediate fix.

Moving Forward

As you can see, Logan already has relatively equitable distribution among the use of its runways. Each configuration has at least two, if not three, runways, and they are decided impartially. Moreover, the Massport Community Advisory Committe is conducting testing that will perhaps result in the developing runway usage plans, which would allow for more equitable sharing of noise, much like the runway alternation program at London Heathrow.

While a solution isn’t on the horizon at the moment, progress has been made. Ultimately, the goal is to ensure equitable distribution of noise while allowing aircraft to operate in a more safe and efficient pattern. Regardless of where you live, we should continue to strive for those ideals.