Roles & Responsibilities and Terms & Resources
Roles & Responsibilities
Raleigh-Durham International Airport (RDU)
The Raleigh-Durham Airport Authority (Authority), like all other airport operators in the United States, has no role or authority over any airspace and therefore does not have control over the flight paths or altitudes that aircraft fly. The role of the Authority is to administer and control the operations and facilities at RDU.
The Authority has a Noise Office to address aircraft noise concerns and to assist with providing the facts, science and regulations associated with aircraft noise. The Noise Office responds to questions and complaints, monitors aircraft operations and noise levels in the community, and meets with individuals, groups, elected officials, airline representatives and the FAA to discuss airport operations.
The Authority also maintains a Flight Tracking System from which it can communicate information about flight movements and noise in real time, analyze flight impacts on neighborhoods, handle complaints and monitor aircraft noise. Click here for RDU’s Flight Tracking System.
Federal Aviation Administration (FAA)
The federal government has exclusive sovereignty over U.S. airspace. The Federal Aviation Administration (FAA) is responsible for managing the National Airspace System including all aircraft flight paths and altitudes. The Airport Noise and Capacity Act of 1990 limits U.S. airports from imposing new noise-based operational restrictions on all aircraft, including limits on airport hours of operation, number of aircraft operations, or aircraft noise levels. For more information about FAA responsibilities, visit their website by clicking here. The FAA also has a noise page available you can access by clicking here.
The FAA also periodically evaluates arrival and departure procedures for RDU and in 2021 will institute new Performance Based Navigation procedures. As part of a public information initiative, FAA produced a presentation and video which describes these new procedures. View here.
Local governments have responsibilities associated with minimizing aircraft noise impacts on their residents. Local government jurisdictions are responsible for all land-use zoning around airports and can implement land use plans that avoid residential areas near airports. The Authority actively maintains communication with surrounding communities regarding aircraft noise patterns in order to help these communities avoid incompatible land uses.
Terms & Resources
dB: The Decibel (dB) is the unit used to measure the magnitude or intensity of sound. The decibel uses a logarithmic scale to cover the very large range of sound pressures that can be heard by the human ear. Under the decibel unit of measure, a 10 dB increase will be perceived by most people to be a doubling in loudness, i.e., 80 dB seems twice as loud as 70 dB.
dBA: The A-weighted Decibel (dBA) is the most common unit used for measuring environmental sound levels. It adjusts, or weighs, the frequency components of sound to conform to the normal response of the human ear at conversational levels.
DNL: Day-Night Average Sound Level. To describe the effects of environmental noise in a simple, uniform and appropriate way, the Federal Aviation Administration established the day-night average sound level (DNL) noise metric. DNL is a metric that reflects a person’s cumulative exposure to sound over a 24-hour period, expressed as the noise level for the average day of the year based on annual aircraft operations. To account for a higher sensitivity to noise exposure at night (occurring between 10 p.m. and 7 a.m.), DNL calculations add a ten times weighting for each nighttime flight, equivalent to each nighttime event being measured as if ten daytime events had occurred: because of the logarithmic scale, this is equivalent to each nighttime event receiving a 10 dBA “penalty” added. This noise metric (i.e., standard) is in use at every commercial airport in the US.
Flight Track: Flight Track is the path an aircraft travels through the air.
Flight Path: Flight path is a term used to show the areas in which aircraft will be flying over. It is important to distinguish flight paths from noise contours. Noise contours are based on yearly averages and extend from the runway ends (e.g., the55 DNL contour extends roughly seven miles from the end of the runway). Flight paths cover a much longer distance. For example, most commercial jet aircraft “line-up” for approach roughly 15 miles from the end of the runway.
IFR: Instrument Flight Rules (IFR) govern flight procedures during limited visibility or other operational constraints. Under IFR, pilots must file a flight plan and fly under the guidance of radar.
Noise: Noise is unwanted sound or any sound not occurring in the natural environment, such as sounds emanating from a leaf blower, outdoor concerts, city and highway traffic, and aircraft. While noise can be measured objectively, each person perceives sound differently. Thus, noise is subjective.
Noise Contour: Like topographical maps showing terrain in an area, Noise Contours are a continuous line on a map that represents equal levels of noise exposure using DNL as a metric and are important to understanding the noise around RDU. These contours do not delineate where aircraft will be heard and not heard, but rather an represent an FAA approved calculation of average annual aircraft noise levels determined using FAA standard methodology
Noise Event: A Noise Event is the measured sound produced by a single source of noise over a particular duration of time. An aircraft noise event begins when the sound level of a flight operation exceeds a noise threshold and ends when the level drops down below that threshold.
Noise Monitors: These monitors collect and present data to the Noise and Operations Monitoring System. The Authority has six noise monitors placed strategically in the community surrounding RDU.
VFR: Visual Flight Rules (VFR) are air traffic rules allowing pilots to land by sight without relying solely on instruments. VFR conditions require good weather and visibility.