FAQ
Frequently Asked Questions
Part 150 is a section of the Code of Federal Regulations (CFR) that sets forth rules and guidelines for airports desiring to undertake airport noise compatibility planning. The Part 150 regulations establish guidelines for technical aspects of aircraft noise analysis and the public participation process for airports choosing to prepare airport noise compatibility plans.
The Part 150 Study involves six major steps:
- Identification of airport noise and land use issues and incompatibilities
- Definition of current and future noise exposure contours
- Evaluation of alternative measures for abating noise that impact the 65 Day Night Level (DNL) noise contour (e.g., changing aircraft flight paths), mitigating the impact of noise (e.g., sound insulation), and managing local land uses (e.g., airport-compatible zoning)
- Development of a Noise Compatibility Plan (NCP)
- Development of an implementation and monitoring plan
- FAA review and approval of the recommended NCP, including the analysis of alternatives, the compatibility plan, and the implementation and monitoring plan.
The Part 150 Study process is designed to identify noise sensitive land uses surrounding an airport, and to recommend measures to both correct existing incompatibilities and to prevent future incompatibilities. For Part 150 Study purposes, noise sensitive land uses are generally defined as residences or public use facilities (libraries, churches, schools, nursing homes and hospitals) within the 65 Day-Night Average Sound Level (DNL) noise contour, the area the FAA defines as impacted by aircraft noise.
The purpose for conducting a Part 150 Study at an airport is to develop a balanced and cost-effective plan for reducing current noise impacts from an airport’s operations, where practical, and to limit additional impacts in the future. By following the process, the airport operator is assured of the FAA’s cooperation through the involvement of air traffic control professionals in the study and the FAA’s review of the recommended Noise Compatibility Program (NCP). The decision to undertake noise compatibility planning is normally voluntary on the part of the airport operator. As part of the Record of Decision for Environmental Assessment for the new parallel runway at CLT, the City of Charlotte has committed to reviewing the Part 150 Study at CLT.
An airport with an FAA-approved NCP also becomes eligible for funding assistance for the implementation of approved measures.
Among the general goals and objectives addressed by a Part 150 Study are the following:
- To reduce, where feasible, existing and future noise levels over existing noise-sensitive land uses;
- To reduce new noise-sensitive developments near the airport;
- To mitigate, where feasible, adverse impacts in accordance with Federal guidelines;
- To provide mitigation measures that are sensitive to the needs of the community;
- To minimize the impact of mitigation measures on local tax bases; and
- To be consistent, where feasible, with local land use planning and development policies.
The Airport officially began the Part 150 Study Update in May 2022. The Part 150 Study Update is scheduled for completion by the end of 2023 when it will be submitted to the FAA for review. The FAA review period is typically 6-9 months.
Field measurements from temporary monitors are being collected for use in the study. The measurements will be compared with pre-existing database information related to aircraft noise level and performance characteristics in the FAA’s Aviation Environmental Design Tool (AEDT). The information collected during the measurement program includes acoustical output, as measured at known locations, as well as flight trajectory data (the aircraft’s three-dimensional location) relative to the noise measurement site. This information is being used to ensure that the input data into the AEDT is as accurate as possible.
No. The FAA is the only entity that can manage aircraft runway operations or aircraft in flight at CLT. Furthermore, as a recipient of grant funds from the FAA, the Airport must abide by specific FAA-imposed obligations and conditions. One of these is that they will not restrict or limit airfield access at CLT based on noise or time of day.
Some airports, like John Wayne Airport in Orange County, still have airfield access limitations, such as curfews on commercial aircraft at night that were instituted prior to the 1990 federal Airport Noise & Capacity Act (ANCA). Except for those that were implemented prior to November 1990, ANCA prohibits regulations or amendments to existing restrictions that limit airfield access. ANCA also required the complete phase out of all louder Stage 1 and Stage 2 commercial aircraft over 75,000 pounds at all airports, including commercial airports like CLT, by the year 2000.
The FAA has developed the Aviation Environmental Design Tool (AEDT) for evaluating aircraft noise impacts in the vicinity of airports. The AEDT is the FAA’s standard tool for determining the predicted noise exposure in the vicinity of airports. The FAA requires the use of AEDT to develop noise exposure contours in Part 150 Studies. The AEDT utilizes flight track information, aircraft fleet mix, aircraft flight profiles and terrain as inputs. The AEDT produces noise exposure contours that are used for land use compatibility maps. The AEDT includes built-in tools for comparing contours and easy export to commercial Geographic Information Systems.
The Day-Night Average Sound Level (DNL) metric describes the total noise exposure during a given period. DNL is a metric used for predicting the average long term noise exposure on a population. In computing DNL, an extra weight of 10 dB is assigned to any sound levels occurring between the hours of 10:00 p.m. and 7:00 a.m. This is intended to account for the greater annoyance that nighttime noise is presumed to cause for most people. This extra weight treats one nighttime noise event as equivalent to 10 daytime events of the same magnitude.
Noise Exposure Maps (NEMs) identify the noise exposure of the current operating conditions, and projected future conditions. Included within this analysis will be the operating conditions taking place at the airport including departure and arrival procedures, daytime and nighttime activity, touch and go operations, runway use, and flight track patterns.
Airlines continue to retire older, noisier aircraft from their fleets and replace them with more modern, quieter, fuel-efficient aircraft. This helps reduce noise levels at airports often times even as the number of aircraft operations increase. Many of the older, louder aircraft that operated at CLT in the early 2000’s have been phased-out or been significantly reduced from commercial airline fleets.
The Airport is committed to continuously reviewing and updating the Noise Compatibility Program for the betterment of the communities surrounding CLT. This current Part 150 Study Update will update the previous studies and will take into consideration the addition of the fourth parallel runway. The Noise Exposure Maps will be updated and based on those any areas that would be eligible for noise mitigation will be identified. The determination of new mitigation programs or changes in flight procedures will be based on FAA guidelines and the availability of funding.