The Federal Aviation Administration (FAA) is the sole organization in the United States that is responsible for the movement of aircraft. Air traffic controllers direct aircraft into and out of controlled airports such as MSN, with the main consideration being safe separation of aircraft and safe operations. The airport cannot require that certain procedures be used, but does work closely with the FAA to develop voluntary procedures to mitigate noise impacts such as the Preferential Runway Use Program.
Dane County Regional Airport submitted a Federal Aviation Regulation Part 150 Noise and Land Use Compatibility Study in 1991. This study was used to determine the aircraft noise levels around the airport and develop recommendations to abate the noise impact as much as possible. The Noise Exposure Maps were approved by the FAA in 1992, and the Noise Compatibility Plan was approved by the FAA in 1993. Most of the recommendations from the study have been successfully implemented by the airport. These include the Preferential Runway Use Program, the Home Sales Assistance Program, construction of a new runway which replaced two existing runways, encouraging aircraft operators to use noise abatement departure procedures, construction of a hush-house for military F-16 aircraft maintenance, establishment of visual approach and departure corridors for helicopters, defining an “airport affected area” to limit incompatible development in noise sensitive areas, purchasing of property surrounding the airport to prevent incompatible land uses, and monitoring and responding to noise complaints.
This program encourages aircraft to arrive from north of the airport and depart to the north. In doing so, the high density residential areas south of the airport are less impacted by aircraft noise. In addition, aircraft operators are asked to abide by certain departure procedures. An example of this is asking aircraft departing Runway 31 to climb to a predetermined altitude before turning left to avoid over-flying surrounding residential developments.
Due to the constraints of aviation safety, wind, visibility, runway conditions, cloud heights, traffic saturation, and other factors will affect the ability of the preferential runway use program to be utilized.
Before runways at any airport are built, a 10-year wind study is performed to determine the direction of prevailing winds in the area. Runways are then designed to take advantage of the prevailing winds. Aircraft need to land and depart into the wind in order to provide lift and maintain safe operations. Runways are numbered according to the direction of the compass degree heading with which they are aligned. The ends of each runway are 180 degrees apart. For example, Runway 36 at Dane County Regional Airport faces north at 360 degrees. The opposite end of Runway 36 is Runway 18, and this faces south at 180 degrees.
The current useable runway lengths at Dane County Regional Airport are as follows:
- Runway 18/36 - 9,005 feet
- Runway 3/21 - 7,200 feet
- Runway 13/31 - 5,846 feet
When a runway is closed, it is not available for use by aircraft arriving or departing, and flights must use the remaining available runways. Runways may need to be closed due to storms or unusual weather. During winter snow storms, every effort is made to keep the runways open and free of snow and ice. Depending on the severity of the storm, it may become necessary to close one or more runways in the interest of safety. Runways may also need to be closed for maintenance purposes. To maintain a safe and efficient airport, runway surfaces and their associated systems need to be maintained in top condition. Another factor that affects runway use is the type of aircraft being used. A very large aircraft can not operate safely if it were to use a runway that was designed for much smaller aircraft.
Different weather conditions can affect the ability of noise to travel. Also, during the summer months, hot, humid weather conditions affect the performance of aircraft and their engines. Colder winter weather, with drier, denser air, increases the efficiency of aircraft and their engines. Weather conditions can have a huge effect on aircraft operating characteristics. Just as you may find it harder to breathe in hot, humid weather, so does an aircraft engine. Because of these differences, aircraft need more runway length to take off and will be slightly lower over surrounding communities. Another weather condition that can affect noise transmission is a condition known as an inversion. This occurs when the air above is warmer than the air at the ground. This condition is opposite the norm, where the air gets colder as altitude increases. During an inversion, the noise that is directed up from the aircraft will ‘bounce’ off the warmer layer of air above and be re-directed back toward the ground.
To safely operate in and out of airports, aircraft must be directed by air traffic controllers. To safely transport passengers, these aircraft must fly into the airport at a shallow angle. When bad weather or low visibility conditions exist, pilots must fly using ONLY instruments that tell them how to get to the airport. Because the pilot cannot see the airport, these instruments will guide the aircraft into a position where the aircraft can be safely landed once the pilot is close enough to view the airport and runway. The approach path for this type of instrument arrival guides the aircraft towards the runway while descending at an angle of about 3 degrees towards the runway end. If the pilot does not view the airport by a certain point, a decision must be made to abort the landing and perform a missed approach procedure. To perform this procedure, the pilot re-applies engine power and gains altitude while under the direction of air traffic controllers. The pilot must then decide whether to attempt another landing or divert to another airport that does not have bad weather or low visibility.
When aircraft are departing, they are also directed by air traffic controllers. The controllers must keep all of the aircraft that are in the air separated by a minimum distance in altitude and also laterally. Aircraft departing the airport generally climb as quickly as possible to minimize the noise impact to surrounding communities. There may be certain instances where a departing aircraft is prevented from climbing quickly in order to keep sufficient separation from another aircraft that is traversing the area, but these instances are rare. The airport, the pilots, and the Federal Aviation Administration are all working together to ensure the safest possible operations, while minimizing the impacts to the communities.
Due to Federal legislation, the Airport Noise & Capacity Act of 1990(ANCA), U.S. certificated airports are restricted from instituting bans on commercial aircraft operations.
Since the passage of the ANCA legislation, no U.S. airport has been successful in restricting access to Stage III aircraft. Stage III aircraft are the quietest available aircraft, according to Federal Aviation Administration standards. All of the commercial airlines and cargo airlines currently operating at Dane County Regional Airport are utilizing Stage III aircraft.
The Federal Aviation Administration is currently working on a noise standard for new aircraft. This standard will be called Stage IV.
The most important thing anyone can do to understand airport operations is to become educated on the ways that airports and aircraft operate. If aircraft operators are following the noise abatement procedures, they are doing their best to minimize any negative effects to the surrounding communities. You can find out the current weather conditions by calling 249-0615 to hear a recorded weather update. If aircraft operators are found to be operating contrary to the noise abatement procedures, the Noise Abatement Officer does follow-up with the operator to determine the cause and request cooperation in the future. You may call the airport’s Noise Abatement Line at 246-5841 to report aircraft noise disturbances. Working together, we can and are ensuring the economic vitality of the region through efficient use of transportation resources, while also striving to be a good neighbor to the surrounding communities.
Information regarding aircraft and airport operations, air traffic control, noise abatement, and Federal Aviation Regulations (FARs) can be found on the internet at http://www.faa.gov/. The Dane County Regional Airport has information available at www.msnairport.com. The airport’s Noise Abatement Officer can answer any questions you may have regarding the noise abatement procedures at Dane County Regional Airport. Please call 608-661-4803.