WELCOME TO NOISE COMPATIBILITY - WE ARE HERE TO SERVE YOU !!



WHERE WE ARE TODAY!

The Memphis - Shelby County Airport Authority is actively addressing environmental issues. We realize that aircraft noise can be a real concern. When considering the needs of our airport neighbors, we continually have been involved in the use of quieter aircraft engines and efforts to reduce incompatible land uses in the vicinity of the airport.

The Memphis-Shelby County Airport Authority's efforts to reduce noise exposure resulted in the 1987 Noise Compatibility Property Acquisition Program commonly called the Part150 Program.  This FAA approved program provided for the acquisition of approximately 1400 single-family residents located within the 75 Dnl noise contours. Spanning over a decade, this program is now complete and we do not anticipate any further property acquisition programs.

In 1989, twenty-seven residential property owners filed a lawsuit against the Airport Authority seeking monetary damages and injunctive relief. This case was later certified as a class action. In November 2000, a settlement was approved by the US District Court for the Western District of Tennessee. The Settlement was fully implemented and the Court discharged the Airport Authority.  Our Noise Compatibility Staff will continue to focus our efforts towards the concerns brought to us by our neighbors. We also will continue to work with the FAA, state and local governments to reduce any negative effects aircraft have on the entire community.

THE PART150 UPDATE

In 1981 the Federal Aviation Administration established the PART 150 Noise Compatibility Planning Process as a part of the Federal Aviation Regulations (FARs), The process is listed as Part 150 under Title 14 of the Code of Federal Regulations and is commonly referred to as “Part 150." Part 150 specifies the methodology and procedures governing the development and implementation of Noise Exposure Maps (NEMs) and Noise Compatibility Programs (NCPs).

The NEM is a graphic depiction of the noise exposure around an airport in existing and future (5-year) operational conditions. Under the Part 150 process, FAA determines whether the NEMs comply with federal requirements of the program. If so determined, a notice of compliance is published in the Federal Register. The Airport Authority recently updated the Noise Exposure Maps for the Memphis International Airport and the NEMs were approved by the FAA on July 29, 2005.

Since our previous update, several factors have occurred that might affect the aircraft noise in areas surrounding the airport. These factors include changes resulting from the previous NCP, an increasing percentage of quieter (Stage III) aircraft, changes in aircraft operations, and a refined FAA noise model. The recent study serves to assess the current (2004) and the future (2009) noise environments, identify compatible and noncompatible land uses within the noise contours by using the following information:

• Location and orientation of all runways and engine run-up areas.

• Flight tracks used by aircraft arriving and departing all runways.

• Airport activity levels which indicate on an annual average daily basis, the number of aircraft by type, utilization of each flight track, in both daytime (7 a.m. to 10 p.m.) and nighttime (10 p.m. to 7 a.m.) periods for landings and takeoffs

• Landing glideslope angles, glideslope intercept altitudes, and engine power settings for each aircraft type to fly that approach profile.

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• Takeoff profiles for each aircraft type, taking into consideration.engine power settings for each aircraft type, takeoff weight, stage length, and noise abatement flight procedures.

• Airport elevation, wind conditions, and average temperature.

All of this is done to determine the most efficient way to reduce aircraft noise.

DID YOU KNOW?

Each person has a different perception of the noise from an aircraft flight and has a different response to it! The aircraft noise a person hears and the person's perception and response to it depends on the characteristics of the noise source and the path the noise travels to reach that person.

	INTENSITY - related to loudness. The sound produced by a Boeing 727 aircraft has a greater intensity than the sound produced by a Boeing 757 aircraft; when flying over at the same altitude, the B-727 is louder.
	FREQUENCY - similar to pitch. Human ears are more sensitive to sounds of certain frequencies (for example, people cannot hear sounds of high frequency such as a dog whistle) Aircraft make sounds over a wide range of frequencies. The sounds from an aircraft takeoff cover a wide range of frequencies, but are generally heard as a low-frequency vibration and rumbling, dominated by the sound of the engine operating at full less than full power, and the sound is generally dominated by the high frequency output of the fan at the front of the engine. This "whine" from an aircraft landing may be more annoying to some people than the sound of an aircraft takeoff, even though the takeoff sound is louder.
	CHANGES IN NOISE LEVEL OVER TIME - A sound that is increasing in level generally sounds noisier than one decreasing in level. The individual noise levels used to calculate the Ldn values take into account both the increase in noise as an aircraft approaches and the decrease as the aircraft passes overhead and gets farther away. A sound that has change in level (such as the "chopping" sound made by a helicopter) generally sound noisier than a sound that does not change frequently.

THE PATH THE NOISE TRAVELS

Aircraft noise travels through air before it reaches a person on the ground. The noise a person hears depends on the certain characteristic of the noise "path":

	WIND - Wind can scatter or redirect noise to other areas.
	WEATHER - Rain, snow, fog, or haze have a very small effect on noise (but they can have a large effect on the number of flights flying over a particular area). Clouds also seem to increase the noise levels on the ground as sound waves are actually reflected off the clouds and back to the surface of the earth.
	TEMPERATURE AND HUMIDITY - As sound travels through the air, some of the sound is absorbed by the air. The amount of sound absorbed by the air depends on the frequency of the sound, the air temperature, and the relative humidity. Under some temperature and humidity conditions, the air can actually "bend" sound and redirect it to a different location.
	PRESENCE OF OBJECTS - When an aircraft is flying over someone's house, the walls and roof help to reduce the noise heard inside. When an aircraft is moving on the ground and there are walls or buildings in the path the noise travels, the noise a person hears may by reduced substantially. This information is intended to help explain the characteristics of noise. It is hoped that this will provide a better understanding for the variance in noise levels heard throughout the days and years and complexity of trying to determine which areas and residents are most affected by aircraft noise. After taking all the variables into account, the FAA has determined that the Ldn measure used in the Noise Compatibility Program is the best available measure to summarize noise effects.

Source: Aviation Noise Effects (Published by the FAA in March 1985).

CONTACT US

Noise Complaint Form

For additional information and concerns please direct correspondence to:
Noise Compatibility Planning Division @ (901) 922-8789.

Noise Complaint Hotline (901) 922-8044.