Noise Compatibility
The Noise Compatibility Program (NCP) at DTW combines the existing approved Part 150 Noise Compatibility Plan with Air Traffic Control Tower (ATCT) requirements to ensure the safe and expeditious handling of air traffic. While safety is paramount to any ATC operation, noise sensitivity to the surrounding communities is also of key importance in airport operations.
Flight Procedures/Runway Use
The Federal Aviation Administration (FAA) is responsible for determining under what conditions flight operations may be conducted without causing degradation of safety. Under ideal conditions aircraft takeoffs and landings should be conducted into the wind. Considerations such as delay and capacity problems, runway length, approach aids, noise abatement, and other factors may require aircraft operations to be conducted in a specific manner.
The ATCT at DTW is managed by the FAA and determines runway use based on achieving safe aircraft operations in compliance with FAA regulations. Weather, wind direction and speed, visibility and cloud cover, schedule load, and noise abatement procedures are all considered when the FAA determines which procedures will be operated at any given time at the Airport. As conditions change, such as weather, ATCT responds by adjusting procedures to ensure safe and efficient operations.
Through the approved NCP and continued coordination with the ATCT and airline operators, the Airport, in concert with the FAA, has developed a preferential runway use program. Presently, the preferential runway use for the Airport is to concentrate noise over the least densely populated areas south of the Airport. When there are high operational demands (many flights arriving and departing) the ATCT will depart aircraft to the south and have arrivals from the north. Although aircraft are generally directed into the wind, this procedure calls for southern departures with up to a 7-knot tailwind to maximize the availability of this procedure. Data shows that the Airport operates in south flow (departing to the south and arriving from the north) about 68% of the time, north flow (arriving from the south and departing to the north) about 30% of the time, and the crosswinds (east/west) about 2% of the time.
Between the hours of 11:30pm - 6am the ATCT operates in reverse flow (also called head-to-head or contra flow) by having departures to the south as well as arrivals from the south. This procedure only applies to nighttime operations.
The majority of the time, the outboard runways (of the four parallel runways, the outboards are the outer east and west runways) are used for arrivals, while the inboard runways are used for departures. Runway use can be aircraft type specific, meaning that different aircraft have different runway uses based upon aircraft size, performance, and location relative to the passenger terminal gates.
In addition to implementing noise abatement runway use procedures, the ATCT direct the departing aircraft in a “fanning” procedure to disperse the noise to reduce impacts on noise sensitive areas. Preferential noise abatement flight tracks have been designated for aircraft departures that disperse or “fan” over noise sensitive land uses.
Noise Generated during Aircraft Engine Maintenance & Ground Run-Ups
Airlines must regularly conduct maintenance or repairs on aircraft systems and engineers. For certain types of aircraft maintenance, engine run-up tests are conducted to demonstrate that the aircraft's in-flight systems are working properly before the aircraft can be put back into service. A run-up is a preflight test of the engine systems, where various levels of engine power are applied while the aircraft remains stationary. a substantial amount of noise can be created when run-up tests occur.
A remedy for this problem is to have all aircraft perform their run-ups in a Ground Run-up Enclosure (GRE). This is essentially a three sided facility in which an aircraft backs in, with the engines facing the walls, and then performs the maintenance check, or run-up. The sound is absorbed into the walls and deflected upwards, rather than outwardly and into communities.
The Airport recently awarded a contract for Architectural/ Engineering services to design a Ground Run-Up Enclosure (GRE). This facility will significantly reduce noise to communities located close to the Airport.
Noise Complaint Response
Noise complaints are evaluated to identify the cause of the noise event and determine if an aircraft is operating outside the noise plan parameters. Noise complaints are not necessarily reflective of the severity of the noise, but can be useful to the Airport in identifying problems and issues that are important to the various communities surrounding the Airport.
Contact Information
DTW’s Noise Compatibility Program Office is available 24 hours a day to receive public comments and complaints by calling (734) 942-3222. If you wish to speak directly with the Noise Manager, you may do so during regular business hours. The public is welcome to stop by the Noise Program Office located in the L.C. Smith Building to speak directly with the Noise Manager, review noise exposure maps, flight paths, noise abatement procedures, etc. Or, you may email us at noise@wcaa.us.