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The Homebuyer's/Broker's Guide to
Compatible
Land Use Around
Washington Dulles International Airport
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Frequently
Asked Questions
- Is aircraft noise a major problem in the Washington area?
Out of a total Washington population of 4.5 million,
less than 300 people complained about the noise of flight operations
from Washington Dulles International or Washington Reagan National
Airports last year. A number of those complaints came from citizens
living well away from the airports. Cooperation between the Airports
Authority and its neighbors and wise land use planning by Fairfax
and Loudoun Counties have so far avoided a noise problem. Our
- and their - goal is to sustain that happy situation.
- Is there a phone number I can call to notify someone if
I feel that an airplane has flown abnormally close to my home?
You can call Washington Dulles International Airport Operations
at 703-572-8215. The Operations office will ask you a series of
questions in an attempt to identify the flight operation to which
you are referring. The person speaking with you may be able to
explain the circumstance for the unusual noise or intrusion during
that call, or it may very well require further research. The record
of your inquiry is sent to the Airports Authority's Noise Abatement
Office where they can determine the precise relationship of an
individual flight to your home and offer you guidance. As part
of its efforts to reduce airport noise and to provide information
to help guide the public policy of local governments, the Airports
Authority maintains a system of sound monitors strategically located
throughout the region. They also obtain radar plots of the precise
flight path of every aircraft using Dulles and National. By putting
the two sets of information together, they can determine whether
the noise you heard was made by an aircraft (and if so, which
one) or by some other source.
- If there is nothing in the sales literature to indicate
the presence of Dulles airport, does that mean the home would
not be affected by aircraft flight operations? No, if
the home is close to Dulles it may well mean that the development
was given an exclusion from Loudoun County's disclosure policy,
or the developer was unaware of the requirement. For most of us,
a home is our biggest financial commitment, so it is best to play
it safe and check.
- How can I tell if the house I'm considering buying is
in a noise impact overlay district? The maps on this guide
will give you a rough indication. A visit to the county planning
office would enable you to review precise maps. Also, if you're
buying a new home, there should be maps in the showroom accurately
locating the plot to the overlay districts.
- Is it possible that I could buy a home today that is relatively
free from aircraft noise and then later find aircraft flying over
my new home? If you only visit a home on a day when wind
conditions are keeping aircraft away from that home, it could
appear totally tranquil. However, under a different weather pattern,
aircraft could be flying over or near that home with great regularity.
Your question is a fine example of why anyone contemplating the
purchase of a home should investigate carefully. That's the best
way to avoid later surprises.
- What time of day is the busiest and noisiest for aircraft
flying in and out of Dulles? As Dulles is an international
and transcontinental gateway, flight activity is greatly influenced
by time zone changes. Consequently, the busiest period tends to
be from around 3:00 p.m. to the middle of the evening. That is
also when most of the larger wide-bodied trans-ocean aircraft,
which make more noise, will operate. Other busy times are first
thing in the morning and around mid-day.
- If I complain about aircraft noise near my home, can't
the airport just make the airplanes fly over a different area?
For safety, economic and operational reasons, aircraft leaving
Dulles are free to take up their desired heading as soon as the
aircraft has gained a safe altitude. On landing, aircraft fly
what is known as "a three degree glide slope" (click
here to see chart). That means they line up with the end of
the runway many miles from the airport and then gradually descend
in a straight line along a three-degree slope, which will bring
them safely to the end of the runway for touchdown.
The Federal Aviation Administration, not the airport, that controls
the aircraft while it's airborne. At some airports where houses
have been built in noise impacted areas, or where physical constraints
like a mountain, or security concerns restrict airspace, the FAA
will set up specific flight corridors. Reagan National Airport
is an example. However, such restrictions can reduce the capacity
of runways and thus an airport's ability to serve regional demand.
For Washington Dulles, good public policy has encouraged commercial
uses in most noise impacted areas and placed restrictions on housing
in noise impacted areas whose construction could not by law be
prevented. Housing in this category as well as in other areas
that will be conscious of flight operations, requires full disclosure
of the airport's presence and the potential for aircraft noise.
The primary purpose of this web site is to prevent potential homeowners
from getting into a situation in which they would feel a need
to complain.
- What is an Ldn - also called a DNL? The federal
government uses a unit of noise awareness known as an "Ldn or
DNL." This is an abstract measure that is the best unit offered
to-date to assess the cumulative "rainfall" of noise from repeated
flight operations. The unit is abstract in that it is not a physical
measure like a height on a contour map. Ldn's are calculated from
a number of factors, some measured, many assumed based on forecasts
of aviation activity many years in the future. The unit gives
more weight to operations at nighttime than during the day.
- I am told aircraft are getting quieter, so isn't it "OK"
to buy homes built closer to airports? It is true that
engine advances have enabled the noise from individual aircraft
to be reduced. But it is the cumulative "rainfall" of noise from
frequent flight operations that is disturbing to most people,
rather than the noise from a single flight. That is why Fairfax
and Loudoun counties have created Aircraft Noise Impact Overlay
Districts around Dulles. The volume of flight operations and the
size of aircraft are expected to increase steadily over the years.
Both add to the intrusive effect on homes near airports.
- Will the aircraft manufacturers continue to make airplanes
even quieter? Yes, for the majority of commercial aircraft,
but the gains are likely to be exceedingly small. The Federal
Airworthiness Requirements (FAR) mandate that commercial aircraft
must meet the lowest noise levels that are "technically feasible
and economically reasonable." The latest jet engines are remarkably
quiet for the power they produce. While the current trend is toward
smaller aircraft operating with greater frequency, it is highly
possible that as the years go by the average size of aircraft
will increase and this will tend to increase the current rainfall
of noise.
- Why do Fairfax and Loudoun Counties have different noise
policies with respect to the airport? The two counties
faced different situations in the early 1990's when they created
their current Airport Noise Impact Overlay Districts. The Fairfax
County side of the airport was largely developed and largely in
a compatible manner. Conversely, the Loudoun side of the airport
was mostly undeveloped. Both counties, however, have the same
intent. They wish to ensure that people do not find themselves
buying homes where the noise impact would be unacceptable to them.
- If homes can be constructed outside the 65 Ldn common
line but not inside it, does that mean that the 65 Ldn line is
a cutoff point for unacceptable noise levels? The noise
does not stop at the 65 Ldn line, which is why Loudoun and Fairfax
Counties have created their airport compatibility policies. Noise
heard on any given day is a function of weather conditions. A
United States Department of Defense study, for example, showed
that noise heard at a given point on the ground from any given
set of aircraft operations can vary from one to three miles with
changes in weather conditions. That is why Loudoun County bases
its policy on a lower measure of noise "rainfall" - 60 Ldn - and
extends its Aircraft Noise Impact Overlay District a mile beyond
that line.
- What is falling airplane syndrome? Many of the
complaints registered as a "noise complaint" with an airport,
in fact relate not to the noise the aircraft makes, but to the
caller's concern that the airplane might crash on them. In some
instances, complaints which referred to the aircraft "above my
house" may relate to an aircraft whose radar track passed a quarter
of a mile or more to the side of the house in question. It is
the complainant's perception of the large mass in the airspace
adjacent to the property which stimulates the concern. Consequently,
no matter how quiet aircraft become in the future, if the airframes
get larger, the level of "flyover nuisance" will increase. The
Ldn noise contours do not allow for this development. It is good
public policy to alert people to the potential presence of aircraft
near a particular home as we all have different attitudes and
concerns.
- Have the planning contours been changed in the past?
In the early 1990's, Congress enacted legislation requiring the
retirement of the noisiest subsonic commercial aircraft. A Maryland-owned
bank then argued that one of their subsidiaries should be allowed
to build houses closer to the airport, as the retirement of the
noisier aircraft would cause the planning contours to shrink toward
the airport. Previous court decisions had upheld the right of
counties to prevent construction of housing inside the 65 LDN
line, but permitted it outside. So the authorities reluctantly
plotted a new 65 LDN planning line and at the request of the counties
a 60 LDN line. Both counties then developed their current noise
policies.
- Does the weather and wind direction have anything to do
with the amount of noise I will hear? Weather has a significant
effect on the noise you will hear. First, the wind dictates the
pattern of operation at the airport on any given day, as aircraft
land and take off into wind. Of equal importance, temperature,
temperature inversions, cloud layers, and humidity affect the
transmission of noise. As these factors change, so the atmosphere's
ability to "carry" noise changes, as will the noise you hear at
any given point on the ground. The planning contours are calculated
against a stated set of weather conditions defined as the "international
standard atmosphere." Under wind and weather conditions, which
vary greatly from that standard atmosphere, the rainfall of noise
represented by the planning contour could in reality be heard
a mile or more outside that contour under certain weather conditions.
The counties have sought to allow for this real world variation
with their noise overlay districts.
- What is the projected growth in passengers and flight
operations at Washington Dulles over the next few years?
Will the growth impact the value of my home?
Click
here to view a chart which shows the airport's capacity and
the level of activity through June 2004. While precise annual
growth will reflect economic conditions, expect substantial growth
in flight operations and aircraft size as the years go by. Residents
in this region are heavy users of air travel. A recent Washington
Post study shows that as a region, we make two and one-half times
as many trips by air as the average American. Some people who
fly a lot find a location convenient to the airport beneficial.
- When I sell my house do I have a responsibility to disclose
the presence of the airport to potential buyers? Yes,
the disclosure rules apply to re-sale as well as to new home sales.
Introduction
County Policies
Maps
Survey
Growth of Dulles
Noise Factors
WATF Recommendation
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