Frequently Asked Questions about PDK and Noise

Why do planes fly over my house?

There are several airports in the metropolitan area besides the DeKalb Peachtree Airport. These include Hartsfield Atlanta International, Briscoe Field in Gwinnett County, McCollum Field in Cobb County, Peachtree-Falcon Field in Peachtree City, and Charlie Brown in Fulton County. This does not even include the other smaller airports in Rome, Cartersville, Gainesville, Hampton, Newnan, Clayton County, Griffen-Spalding County, Covington, Monroe-Walton County, and Winder-Barrow County. The FAA designs airspace throughout the Atlanta metropolitan so air traffic will occur over all areas. However, overflights will occur more frequently the closer you are to the airport and its flight patterns.
 

Guide to PDK's Traffic Pattern and Touch & Go Operations for Non-Pilots

Planes seem to be flying over my house on purpose.  Why?

When a plane or helicopter is over your house, it is on its way to or from somewhere very specific. Pilots do not have the time in this busy flying area to single out one house or yard from another and are usually too high and far away to see details.

 

Why don’t airplane owners get rid of those noisier jets?

Aircraft owners like everyone else manage their transportation budgets very much like automobile owners - they trade in their vehicles for a newer model when it is economically advantageous to do so. For the commercial service airlines, the FAA mandated a phase-out program designed to provide noise relief without undue economic burden on aircraft operators. This was done during most of the 1990's, so it was not done overnight. However, there is currently no legislation in Congress requiring “hushkits” or newer, quieter engines on jets that weigh less than 75,000 pounds. The vast majority of the jets using the airport weigh much less than 75,000 pounds, and the ones that weigh more must be Stage III noise compliant, just like the commercial airliners. Stage III aircraft are the quietest aircraft available using today’s technology.

 

Why are planes taking off to the south when there is no wind blowing?

To enhance the performance of the aircraft and the safety of the operation, the pilot must takeoff and land into the prevailing wind if possible. Often, due to the wide open spaces of the airport, the winds at the airport will be different than in the local neighborhoods. Buildings, fences, trees, etc., will diminish the wind effect in the neighborhood.

 

Second, the airport’s precision instrument approach brings airplanes in for landing to the south. When this approach is being used, this requires that aircraft take off to the south to maintain a uni-directional traffic flow.

Why can’t airplanes taking off to the south climb higher and fly farther south before turning so they don’t fly over my neighborhood?

Planes generally follow a traffic pattern that is set into place by the FAA. Jets cannot fly farther south before turning, because they would run into the large amount of airspace that is used and controlled by Hartsfield-Jackson Atlanta International Airport (ATL). It is important to remember that airspace has a vertical as well as a horizontal dimension, and ATL imposes many restrictions on the use of airspace by the outlying airports like PDK. Additionally, the approaches into other airports, such as Fulton County's Charlie Brown Field, also take place to the south of PDK.
 
Ensuring clearance of physical obstructions, such as the group of tall radio/TV towers to the south of PDK, also require the dispersement of aircraft to the east or west after takeoff.
 

Guide to PDK's Traffic Pattern and Touch & Go Operations for Non-Pilots

 

Who can do something about low-flying planes & helicopters?

The FAA’s Flight Standards District Office or “FSDO” investigates low-flying aircraft or aircraft that are reported to be flying in an unsafe manner. Call 404/305-7200 to report such activities. The airport has no jurisdiction over aircraft in flight or their altitudes.

 

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Has the airport changed its flight patterns?  Is that why I notice increases or decreases in the number of airplanes over my house?

The Federal Aviation Administration (FAA) through the Air Traffic Control Tower located on the airport controls the movement of all aircraft on the ground and in the airspace over and around the airport. The FAA has NOT changed or attempted to change without airport knowledge any flight patterns into or out of the airport, except in an effort to work with the airport to direct aircraft over the busiest roads, the Interstates, and the MARTA and railroad tracks. As was discussed above, the flight patterns change due to bad weather and/or wind conditions, and these patterns are generally used only temporarily until the wind or weather condition subsides.

 

Why is PDK's nighttime curfew voluntary?

The Federal government has designated PDK as being essential to the nation's air transportation system. Therefore, PDK cannot deny access to the airport to any specific user; this would be considered a "discriminatory practice". Also, because PDK is a public-use airport, it cannot limit its hours of operation to only specific periods of the day or night. Consequently, PDK has set up a voluntary curfew program, and this particular program is heavily promoted in as many venues as possible.

 

The voluntary curfew is listed in as many pilot reference materials as we can find. In fact, the airport has published its own noise abatement pamphlet to get this information out to as many users as possible. Unfortunately, many of the operators who fly at night are not able to alter their hours of operation due to the nature of their business. Such operations include aeromedical operations, bank check and newspaper deliveries, pubic safety (police), etc. But, PDK actively identifies and then solicits operators at night to reschedule their operating hours and has been successful in many instances.

Why wasn't I informed that I lived next to an airport when I moved in?

There is no DeKalb County requirement that sellers or realtors disclose to a buyer that they are nearby an airport. The responsibility ultimately lies with the buyer to research the area and satisfy his/her concerns.
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What is “aircraft noise”?

Aircraft noise is most apparent during jet takeoffs and landings. Takeoffs generally produce the most noise, and the noise comes from when the high pressure jet exhaust mixes with the cooler air outside the engine.

 

How can jet engine noise be minimized?

While many factors determine how aircraft noise affects us, the jet engine is the most significant producer of what we would normally consider “aircraft noise”. Consequently, the jet engine is the single most point at which noise can be minimized. This is why the FAA adopted regulations requiring commercial jets to meet noise standards. Unfortunately, these regulations only apply to aircraft weighing more than 75,000 pounds.

 

The large fan-jet engines in modern Stage 3 aircraft muffle the noise by reducing the speed of the engine’s exhaust. In landing, these Stage 3 engines emit a hissing or humming sound when pilots reduce power to slow down to landing speed. As technology continues to progress, the newer Stage 3 engines are even better than the older engines. The sound has been diminished by lowering the speed of the fans and installing sound-absorbing material within the engine itself.

What are the other factors that contribute to aircraft noise?

Weather – in bad weather, engine noise may reflect off thermal layers in the atmosphere, making jets sound louder than on clear days.

Storms – air traffic controllers will direct pilots around storms, or pilots may request to deviate around a storm based on weather radar returns presented to the pilots in the cockpit. These deviations for regular flight patterns may take planes over areas not normally affected by aircraft noise.

Routes/airspace – much of the airspace around the PDK Airport is affected by the surrounding airports of Hartsfield International, Fulton County, and Dobbins Air Reserve Base.

Emergencies – an emergency may prevent an airplane from landing, requiring the pilot to make an additional approach to the airport or to use an irregular, non-standard route to and/or around the airport.

Weight – a more heavily loaded aircraft may affect the aircraft’s rate of ascent keeping the noise closer to the ground for a longer period of time.

Isn’t it true that big aircraft means BIG NOISE?

It used to be true that the bigger the aircraft the more noise it produced. However, all aircraft weighing more than 75,000 pounds must be Stage 3 compliant. When the FAA enacted rules that stated all aircraft weighing more than 75,000 must comply with Stage 3 requirements, the greatest effect was on the commercial service aircraft. However, if ANY aircraft weighs more than 75,000 pounds, the aircraft must be Stage 3 compliant whether it is used in commercial passenger service or whether it is a modern business jet. Consequently, the bigger, newer aircraft will be the most quiet in takeoffs and landings. Nowadays, the smaller, lighter, older aircraft are usually the most noisy. From the chart below, you can see that the newer aircraft which include the latest in technology including new engines are the most quiet.
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Model (Stage) Maximum Takeoff Weight Takeoff decibels
Learjet
23 (2) 12,500# 88.0
25 (2) 16,000# 93.5
28/29 (2) 15,000#  87.0
31 (3) 16,000# 81.0
35/36 (3) 18,000# 84.5
55 (3) 21,500# 86.3
60 (3)   23,100# 70.8
Canadair
CRJ 53,000#   78.7
Gulfstream
II (2) 65,500#   92.5
IIB/III (2) 58,500#    91.1
IV (3) 73,200# 75.8
V (3) 90,500# 83.3
Boeing
727/200 208,000# 102.4
737/400 139,000# 82.4
747/200 820,000# 102.1
757/200 255,500 86.8
767/200 282,000# 87.7
(from FAA Advisory Circular (A/C) 36-1-Noise Levels of US & Foreign Certificated Aircraft Measured in Effective Perceived Noise Levels)