In 1990, the Airport Noise and Capacity Act required civil subsonic turbojet  aircraft weighing more than 75,000 pounds to comply with stage 3 noise  standards by December 31, 1999, or be retired from service. Objectives, Scope, and Methodology

The Subcommittee on Aviation, House Committee on Transportation and  Infrastructure, and several Members of the House of Representatives asked  us to address four sets of questions about federal programs for airport  development and the alleviation of airport-related noise:
What kinds of projects that reduce airport-related noise or mitigate its  effects are eligible for federally authorized funding, how do FAA’s  selection criteria affect which projects are funded, and to what types of  projects have the funds been historically distributed? What aircraft noise standards apply to civil subsonic turbojets, and why  are some civil subsonic jets not required to comply with these and  earlier noise standards? To address the first set of questions—on the eligibility of noise-related  projects for federally authorized funding—we (1) reviewed the statutory  provisions and FAA’s regulations, policies, and procedures for funding  projects under the AIP and the PFC program to identify project eligibility;  (2) reviewed the statutory requirements for airport-related noise  compatibility programs, as well as FAA’s regulations and processes for  implementing those requirements; (3) obtained FAA’s data on federal grants  awarded for noise-related projects and passenger facility charges approved  for noise-related projects to identify the types of projects and the total  project funding by fiscal year for each type of noise-related project. Unlike most projects funded  with AIP grants set aside for noise-related projects, however, PFC projects  do not have to be part of an FAA-approved noise compatibility program. Land Acquisition and Soundproofing Projects Receive the Majority of AIP and PFC Noise-Related Funding

More than 75 percent of all AIP funds and over 50 percent of all PFC funds  spent on noise reduction or mitigation have been used to acquire land and  to soundproof buildings. Required by law to select a single  method for measuring the impact of airport-related noise on communities,  FAA chose a method that measures community exposure levels and that  gives greater weight to the impact of flights occurring during the nighttime. Principal methods for measuring cumulative average  noise levels identify geographic areas exposed to the same noise levels but  apply different weights to flights occurring during different times of the  day. This effectively adds 10 decibels to the noise produced by each takeoff or landing that occurs  during those nighttime hours. The second and third  methods are considered to have only small differences. Those standards are generally based  on an aircraft’s weight and the number of engines and generally allow  heavier aircraft to generate more noise than lighter aircraft. Looking to the future, FAA has announced five short-term actions  under its Land Use Planning Initiative, which it launched to help prevent  incompatible land uses. Reviewing the comments provided by the aviation  sector and the general public, we identified four principal areas of concern  associated with the initiative. They believe the draft report (1) did not fully  recognize, in its discussion of the potential impact of growth in air traffic,  the significant progress that the Congress, FAA, airports, and the airlines  have made in reducing the number of people exposed to noise from  aircraft, nor did it recognize that aircraft used to achieve additional growth  may be quieter; (2) did not fully reflect the role of international agreements  and obligations related to noise control; (3) was overly broad in its  discussion of  flight procedures for abating noise when explaining why FAA  did not require aircraft weighing 75,000 pounds or less to be retired if they  did not meet stage 2 standards; (4) included only two aircraft in the airport  model, one of which is no longer being produced, and did not address  current production aircraft; and (5) did not fully reflect the relationship and  potential trade-offs between noise stringency standards and aircraft  emissions.
Why GAO Did This Study

Pursuant to a congressional request, GAO provided information on airport-related noise, focusing on the: (1) types of projects that are eligible for federally authorized funding to reduce airport-related noise or mitigate its effects; (2) differences in the major methods for measuring the impact of airport-related noise; (3) Federal Aviation Administration's (FAA) noise standards for civil subsonic turbojets and the reasons some of those aircraft are not required to comply with these or earlier standards; and (4) status of FAA's Land Use Planning Initiative and the major issues the initiative has raised about how best to address airport-related noise.

What GAO Found

GAO noted that: (1) most projects that reduce airport-related noise or mitigate its impact are eligible for federally authorized funding; (2) to be considered for funding under the Airport Improvement Program (AIP), a project must be part of a FAA-approved noise compatibility program; (3) in selecting which noise-related projects to fund, FAA gives priority to projects affecting communities exposed to noise levels of 65 decibels or higher, as determined by FAA's chosen measurement method; (4) in contrast to projects funded by AIP, projects funded by the Passenger Facility Charge program do not have to be part of a noise compatibility program; (5) since the programs began, 75 percent of the grants and over 50 percent of the passenger fees approved for noise-related projects have been used to acquire land and soundproof homes and other buildings; (6) the three principal methods for measuring community exposure are mathematical calculations that differ in the impact each places on noise from flights that occur during different times of the day: (a) one method treats the impact of all flights equally whenever they occur; (b) the second method differs from the first by assigning greater impact to the noise from each flight that occurs during the nighttime than to flights that occur during other times; and (c) the third method assigns additional impact to evening flights as well as nighttime flights; (7) noise standards for regulating aircraft noise from civil subsonic turbojets are generally based on an aircraft's weight and number of engines; (8) the heavier the aircraft and the greater the number of engines, the more noise the aircraft is allowed to generate and still comply with the required noise limits; (9) the newest set of standards--stage 3 standards--apply to all aircraft weighing more than 75,000 pounds and to newly manufactured aircraft weighing 75,000 pounds or less; (10) these lighter aircraft did not have to be retired under earlier noise standards because FAA concluded that it was questionable whether the technology existed to modify those aircraft in a cost-effective manner; (11) under its Initiative, FAA announced five short-term actions in May 1999 designed primarily to provide information that state and local governments can use to improve the compatibility of land uses near airports; and (12) based on comments provided by the aviation sector and the general public, there are four principal areas of concern associated with the Initiative.