Palisades residents are unhappy about noise generated by flights coming in and out of Reagan National Airport (DCA), and they’re speaking up about it. There are a few different ways for planes to fly into DCA, and when it comes to noise, the route they take makes all the difference.

The River Visual (red), LDA (yellow), and RNAV RNP (green) approaches into DCA. Base image from Google Earth.

At the request of nearby residents, DC delegate Eleanor Holmes Norton convened a meeting with the Metropolitan Washington Airports Authority (MWAA), Federal Aviation Administration (FAA) and local residents in Northwest Washington last Wednesday. They discussed ongoing issues with noise from jet traffic landing and departing at nearby DCA, which residents say have gotten worse in recent years.

Several residents recently told WAMU’s Martin DiCaro that the problem stems from the FAA’s new satellite-based “NextGen” procedures for bringing aircraft closer to their homes, particularly in the last two years. Others cited an American Airlines flight from DCA to Chicago O’Hare that takes off just after 5:00 am.

Area resident and GGW contributor Nick Keenan says that having to stop conversations with neighbors because an aircraft is passing overhead is so common that it has a name: the “Palisades Pause.”

Residents also say aircraft are flying lower to the ground and farther from the Potomac River (which puts them over the neighborhood) than they used to. Keenan says there is a huge difference in noise levels between aircraft flying over land versus over the river, despite the distance being just a few blocks on the ground. Rough distance and decibel calculations show that this difference accounts for a 50-60% decrease in noise for residents.

Finally, residents add that MWAA removed altitude information from a tracking system that was set up to catch noise violations when they complained about the change in altitudes.

The issue is where planes are flying

Passenger counts at DCA are at record highs, it has become the region’s most popular airport in recent years. Extra “slots” were added between 2000 and 2012, and Congress has made numerous exceptions to the 1,250 nautical mile limit for nonstop flights from DCA. However, since private aircraft now have onerous security procedures to land at DCA, overall aircraft counts have still not rebounded to pre-9/11 levels. In fact, more airplanes landed at DCA in 1959 than in 2014.

Aircraft have also gotten quieter over the years. An older 727 is 2.8 times louder than the 737-800 series that is used on the early morning Chicago flight. So it is unlikely that any changes in recent years are the cause of additional noise pollution on the ground.

Instead of more aircraft, it might be where the aircraft are flying that is causing the additional impact to residents. Landing aircraft now have a new approach course to choose from, which is detailed below.

One common flight path avoids neighborhoods, while another doesn’t

When the winds are out of the south, aircraft land and take off in a southbound direction (into the wind). Aircraft landing from the north have a choice of three approaches to land at DCA, which have seen only minor changes over the years. All three begin at about 3,000 feet above sea level, at a waypoint over the Congressional Golf Course, near the American Legion Bridge. (When aircraft take off to the north, departure courses are roughly the same, but higher, and in reverse.)

The best known approach for aircraft landing from the north at DCA is the River Visual approach which some pilots call the “Slam Dunk.” Pilots follow the river (they may cut the corner over CIA Headquarters), and descend to recommended altitudes of 1,800’ at Chain Bridge, 1,200’ at the Georgetown Reservoir, and 900’ at the Key Bridge.

Since this approach is never flown by autopilot, it does leave some leeway for aircraft to stray from the prescribed course, both vertically and horizontally. If an aircraft is slightly off course to the left, it increases the noise on the ground in the Palisades or Georgetown. Here is the view from the cockpit of the River Visual approach (begins at 4:14), which shows how fluid the directional changes can be. If the aircraft gets to the left bank of the river, residents of the Palisades will certainly hear it.

When the clouds are below 3,500’, and/or visibility is less than three miles (that is, if you cannot see the Washington Monument from Columbia Heights or RFK Stadium), and often at night, pilots fly the LDA approach, in a straight line from the starting point to the 14th Street Bridge, then visually to the runway.

This approach is easier to fly, and more closely resembles approaches at other airports, but it takes aircraft directly over the Palisades neighborhood. Aircraft descend to 1,700’ near the corner of Arizona Avenue and MacArthur Blvd, and to 1,100’ near the Canal Road entrance to Georgetown University. Residents may assume an aircraft on this approach is “off course” because it is not flying the more familiar path over the river, and thus creating more noise than they expect.

This means planes may be flying as low as 1,000 feet above ground level in the Palisades. Unlike the visual approach, the altitudes here are mandatory minimums (aircraft must be at or above them), not recommendations. If Air Traffic Control identifies a pilot that flies below these, or “busts minimums”, they can receive a violation. Because of its direct route across the neighborhood, and slightly lower altitude, this straight-line approach undoubtedly creates the most noise on the ground.

It’s possible to have the best of both worlds

The newest approach, implemented in 2007, is the GPS-based RNAV RNP approach, which mostly follows the river, is flown almost entirely by autopilot, and can be flown in all weather. The approach follows a more precise GPS course that follows the twists and turns of the river. The only catch is that aircraft and crews must be certified to fly this type of approach.

Aircraft descend at a constant rate through 1,500’ just upstream from the Reservoir, to 955’ at Rosslyn. While the RNP approach keeps aircraft at about the same altitude, it reduces noise because aircraft stay over the river, on a constant descent, with fewer noisy changes in power to the jet engines.

While residents say that new procedures have made noise worse, this approach should have helped matters.

Photo by Photo Phiend on Flickr.

Eleanor Holmes-Norton has proposed cutting the number of DCA-based flights

The classic response to anyone complaining about noise pollution is to ask whether the person was aware of the source when they purchased (or moved into) their property. Section 20 of the Montgomery County Real Estate Contract has a specific reminder of nearby airports and heliports. And while buying property in the District doesn’t bring with it a similar warning, it’s reasonable to expect future residents to anticipate some ambient aircraft noise.

However, this disclosure does nothing for residents if there has been a significant change in noise levels.

Holmes-Norton suggested reducing the number of flights into the airport in response to the increased noise, and tightening the distance limit on nonstop flights. But this would be a loss to the regional economy: cutting four flights per day would cost the District about $10 million per year in economic benefits derived from DCA, based on the MWAA estimate of $2 billion of annual direct and indirect revenue to the District from the 847 daily flights to and from DCA.

Also, cutting the number of flights would likely have no impact on noise. As one resident told me, one flight per minute is just as disruptive as one flight every twenty seconds. Airlines would use the same aircraft to fly, whether it be to Chicago or Seattle, so the distance limit has no effect on noise levels.

Keeping more flights over the river would make the Palisades quieter

The flight paths are in place for a reason, and safety is always the top priority, so the procedures themselves are unlikely to be changed. But pilots and controllers do have a say in which one gets flown on any given flight. MWAA has noise sensors throughout the corridor to quantify decibel levels on the ground, which means everyone can work off of the same data rather than anecdotal evidence or complaints from one side or the other.

MWAA recently turned off real time reporting on these sensors (which work fine at LAX and other airports), but turned it back on this week. This is a good first step to regain the confidence of neighbors.

As noted earlier, different aircraft have very different noise profiles, and there is a lot of demand to fly in and out of DCA. MWAA could tie future gate allocation (or fees) to a record of lower readings on the noise sensors, which may mean a louder aircraft making a point of requesting the RNAV RNP or the River Visual, rather than the straight-line LDA approach, and the use of quieter aircraft. (Note that this does not necessarily mean reducing capacity. Some new airliners are quieter than a four-seat Cessna.)

In addition, encouraging all aircraft to be certified to fly the RNAV RNP approach, so that they can fly all of their approaches over the river, could double the distance between the jet engine noise and residents on the ground along much of the river. That’d decrease ambient noise significantly.

As with all major infrastructure, there are tradeoffs to living in a region where everything is so accessible to so many people. An honest and ongoing dialogue based on empirical data instead of anecdotal complaints, coupled with creative solutions, can assure that everyone can peacefully coexist.

Joe Fox has been a local resident for over 30 years, and currently lives and works in Silver Spring. He tries to travel around the area via as many modes as possible, including car, metrorail, bus, bicycle, kayak, and light aircraft. He works as an IT Program Manager, has worked as a traffic reporter in Washington and Baltimore since 2007, and is an active flight instructor in fixed wing aircraft.