Donald W. MacGlashan


Citizens for the Abatement of Aircraft Noise, Inc.

before the House of Representatives Subcommittee on Technology

The Hon. Constance A. Morella, Chair

October 21, 1997



Thank you for inviting Citizens for the Abatement of Aircraft Noise (CAAN) to present the citizens' side of the aviation noise issue. By holding this hearing this subcommittee demonstrates that it is aware of the growing noise problem for the people living near airports. The fact that experts are predicting a doubling of aviation growth in the next 10 years emphasizes the urgency in dealing with this problem while there is still time to achieve cost effective solutions.


The Extent of the Problem

The first question one should ask is: Is there a noise problem and if so, what is its magnitude. I will try to address that question by using the Metropolitan Washington area, the communities CAAN represents, as an example.


By way of background information, this region has four large airports, Washington National, Dulles International, BWI, and Andrews AFB, plus a number of smaller general aviation fields. National and Dulles are operated by the Metropolitan Washington Airports Authority. From 1990 census data we can determine that over 900,0001 people are being impacted by the noise from these two airports. Recently the Airports Authority has provided to the local communities quarterly reports which tabulate the monthly noise measurements for each of its 32 noise monitoring stations which are located near the two airports, along the Potomac River where much, but not all, of the National Airport traffic flies, and around the Dulles Airport area. Data collected by the Authority 2 over the past nine months show that, in any given month, from 31 percent to 53 percent (see Exhibit 1) of the noise monitoring stations are reporting Day/Night Levels (DNL) that are greater than 65 dB, a standard set more than 20 years ago and 10 dB higher than recommended by the Environmental Protection Agency (EPA). So what does this standard mean? Having lost their case with the Federal Aviation Administration (FAA) and FICAN to establish the 55 dB standard, the EPA and the American National Standards Institute agreed (ANSI standard No. 3.23) in the 1970's that single and multiple family residential property with outdoor usage are incompatible with day-night levels above 65 dB. And yet we are now measuring DNL levels as high as 72 dB, and none of these properties has received federal money for noise mitigation. Neither has the FAA or the Airports Authority made any operational changes to mitigate the noise beyond the daytime noise abatement procedures put in place 30 years ago or the National Airport nighttime procedures of 16 years ago.


It should be remembered that the DNL value is an average taken over 24 hours. This averaging process smooths out the peaks, and it is the peak aircraft noise which is so intrusive. Noise levels at 85 and 95 dBA are not easy to ignore, especially at night when one is trying to sleep. Also remember that at National Airport, nighttime flights, between the hours of 10 p.m. and 7 a.m., are restricted to three of the quietest types of aircraft, the 757, the A320, and the MD 90. This restriction reduces the number of night flights to about three dozen. What this means is that the average daytime noise level appears to be lower than it really is. It is, by deduction, considerably higher than 65 dB.


Unfortunately, the people living near Dulles receive no nighttime relief because there are no nighttime restrictions. The people of Reston, Virginia - over 40,000 of them - for example, have to live in an environment of noise which stays about 70 DNL. With the knowledge that the Airports Authority is currently engaged in a major effort to bring in more carriers and add more flights to existing carriers, the noise level can only get worse, in spite of the phase out of all Stage 2 aircraft by the year 2000.


One might well ask if Washington D.C. is a unique situation. From my contacts with other citizens groups around the country, similar situations exist; high DNL numbers and very little being done to mitigate the problem. The citizens near Denver International Airport (DIA) report that their ambient noise level is 20 dBA, and when aircraft pass over them, the noise level rises to 77 dBA, even 50 miles from the airport. 3 This has caused a severe impact on these people judging by the 2000 complaint calls per month. In Seattle, WA, independent noise experts found that the airport had not done enough to reduce perceived on-the-ground noise impacts from airport operations. 4, 5 At Chicago's O'Hare Airport which is surrounded by residential communities, 20 out of 23 (87 percent) noise monitoring stations are reporting DNL's over 65 dB 6 (see Exhibit 2) with several locations at 80 dB. In one of the adjacent O'Hare communities, 55 percent of the daily flights reached peaks above 95 dBA! Little A.I.P. money has been expended to improve the insulation quality of the communities around O'Hare. With this mounting evidence, there seems to be no question that aircraft are creating a serious noise problem across the country. With the predictions of aviation growth, it is certain to get much worse before any improvement can be expected.


Other Aviation Noise Sources

There is another source of aviation noise, noise from helicopters. In some areas of Washington D.C., helicopters create more of a noise problem than jet aircraft because helicopters in these areas seldom fly over 1000 feet, more typically 500 feet. This low altitude is often required by FAA regulations. Recent attempts by citizen groups in California to raise the minimum altitude to 1000 feet were rejected by the FAA. We recognize that some of these flights have to fly low, for example, medivac, police and National Park rangers. However, the presence of the Pentagon and other nearby military facilities result in many training flights directly over the heavy residential areas. We have to ask the question: do we need that many military exercises in this area and do they have to fly at less than 1000 feet? A reduction in military training over the city and suburban areas would do much to alleviate the noise from this source.


There appears to be no noise standards for helicopters. CAAN suggests that this issue needs attention and that noise standards need to be established.


The Government's Role

Many years ago, Congress gave the FAA three missions; to achieve safety of flight, to promote the aviation industry (until recently) and to control the environmental impact of aviation activities. The FAA has done a good job with the first two missions, although there are numerous critics regarding the safety issue. The third mission has been a stepchild with the FAA, resulting in little meaningful reduction of noise for the people on the ground. Yes, the Stage 3 aircraft are quieter than the Stage 2's, but reducing the sound level from about 95 dBA to 87 dBA is not perceived to be a great achievement by ground-based citizens. Additionally, the size of commercial aircraft has been increasing so that larger, more powerful engines are needed to move them. The noise reduction achieved by Stage 3 design is being offset by these larger aircraft.


Aviation noise reduction has been achieved in some measure by property buy-outs and by insulating schools, hospitals, and homes when the DNL was 65 dB or greater. Much of this money came from the Federal Airport Improvement Program. The results have been mixed; good for the affected hospitals, fair for the schools and not very effective for homes. For homes, it has been a case of too few done, and no discernible benefit due to poor quality work.


Defining Noise

We will never resolve the noise issue until we can all agree on what the standards should be. The question to ask is: what constitutes excessive noise and at what level does this noise cause psychological and physiological damage to people? There is a mounting body of evidence which says that excessive noise causes learning impairment, sleep deprivation, reduction in job performance, and damaging stress levels.


Years ago, before Congress de-funded the EPA's Office of Noise Abatement and Control, the EPA argued that the DNL should be set at 55 dB, not 65 dB. As stated above, the 65 DNL standard won out and has been a sacred cow ever since. It is, however, a flawed metric. It effectively leads one to believe that the noise level is not too bad because it averages all the noise over a whole day, masking the real noise that people experience. It is therefore a fictitious number with no relationship to what is really happening. In California and many European countries, a different metric is used. It is called the Community Noise Equivalent Level (CNEL) and it imposes a 5 dB penalty to the DNL value for the hours between 7 p.m. to 10 p.m. - to promote communications and relaxation during those hours - in addition to the 10 dB penalty for after 10 p.m. hours. However, even the CNEL is imperfect because it does not account for the single event noise level, that intrusive noise that a turbojet makes when it passes. Therefore, what is needed is a metric which takes into account the single noise event. Its formulation should include a combination of the peak noise value and the frequency of single events. The National Resource Defense Council has discussed the noise issue is in its publication, Flying Off Course. 7


Having a new DNL standard will ring hollow if there is no mechanism to enforce it. As the current airport data indicates, many people living near airports are in an unhealthy noise environment - over 65 DNL - and still more are living in a marginally acceptable noise environment. Right now there is no cap as the evidence indicates, so the noise standards we have are basically useless to control noise. We need legislation to enforce a cap on the amount of noise people have to live with. The Netherlands has just such a cap and because Schiphol Airport has exceeded it, has had to stop nighttime flights and eliminate the use of one parallel runway.


Some years ago the FAA has sponsored studies that concluded that only about 12 percent of the people are highly annoyed by noise. This figure, however, has been disputed by other studies which indicate that the percentage is much higher. Even if we use the 12 percent figure, for the Washington D.C. area, it would mean that there are over 100,000 people who are highly annoyed by aircraft noise and may be being damaged by that noise. If 100,000 people in a single metropolitan area were discovered to have a debilitating but preventable disease, and the authorities were ignoring it, that would be a national news event. More and more scientists in the country think that people are being damaged by excessive noise and that we can no longer ignore the issue. 8, 9 Even if there were no growth in the volume of traffic at these two airports - and we do not expect that - we are saying that these people may have to live in an unhealthy environment until enough of the Stage 4 aircraft are used to reduce the noise level to safe levels. That time is probably at least seven years away.


Given the record of the FAA for managing the aircraft noise issue, CAAN has no confidence that the FAA can resolve the problem, particularly when noise issues come in conflict with their second mission responsibility - to promote the aviation industry - which although formally rescinded is still there as a cultural legacy. The responsibility for noise standards and their enforcement, CAAN feels, should be returned to the EPA.


Future Goals

The noise problem is not going to go away anytime soon. Technology created this problem and technology is what will have to provide the ultimate solution. What has to be done differently is to stop ignoring it or denying that it exists. Because it took enormous sums of money to arrive at the present situation, we will need to invest large sums of money to extricate ourselves from the problem. CAAN feels that more emphasis should be placed in research to quiet the turbojet engine and its supporting nacelle structures. Achieving meaningful noise reductions may require solutions which cost more than the airlines would like. But if they wish to continue to use inner city airports like Lindbergh Field in San Diego, Midway in Chicago, and National in Washington DC, then that is the price they will have to pay.


As was indicated above, we need a new noise metric. A panel of experts, independent of the FAA, should be convened to design this metric. In conjunction with this effort, the Government should sponsor independent studies on the health effects of aircraft noise. The results of these studies should form the basis for establishing new standards which should then be used in setting the noise reduction goals for Stage 4 aircraft. If the Stage 4 aircraft performance falls short of the new standards, noise mitigation techniques and flight operational changes must make up the difference. One should always keep in mind that the health of the people comes first. Industries must develop technologies to ensure that this remains true.


In 1990, Congress mandated that by the year 2000 all Stage 2 aircraft would be retired from service or converted to Stage 3 standards. The year 2000 is rapidly approaching, so now is the time to begin the process of establishing new standards and timetable to phase in the Stage 4 aircraft.


CAAN is aware that Stage 4 aircraft will not, in all likelihood, reduce the single event noise levels to much below 65 dBA. For this reason, we recommend that money go into promising alternatives. One that has received some publicity is a modern version of the auto gyro aircraft. Reports are that it is capable of vertical takeoffs and landings, and normal aircraft propulsion in level flight. 10 NASA has provided a grant of $70,000 to assist in its development. We recommend that grants continue to be awarded to investigate these types of alternatives.


Immediate Solutions

There are two things CAAN believes could be done to reduce some of the aircraft noise at inner city airports. They are:

use the aircraft Flight Management System (FMS), to fly the aircraft at a reduced but safe climb rate. Currently the the FMS is programmed to maintain a prescribed engine power ratio (EPR) after the initial takeoff sequence. A single value EPR will result in far more rapid climb out in cold weather than it will in hot weather. Therefore, by using climb rate instead of EPR, some noise reduction should be achieved, at least in the colder months.

using the regional jet for most of the flights. This aircraft is smaller and therefore quieter. There may, however, be a risk of more air pollution if the number of flights are not properly balanced.



In conclusion, CAAN feels that aircraft noise is a serious as well as complex problem with far more health consequences than previously recognized. We believe that new noise standards, keyed to health risks, need to be established as well as a new metric for measuring noise. We urge this subcommittee to recommend that a new timetable for the introduction of Stage 4 aircraft, and we would urge that more research dollars be applied to study ways to alleviate the excessive noise problem around our nations' airports.




1. Data derived from 1990 U.S. Census. Only population from zip codes around airports and under flight paths were included.

2. Metropolitan Washington Airports Authority,Flight Operations and Aircraft Noise Quarterly Report for Washington Dulles International Airport and Washington National Airport, Three reports covering the period October 1996 though June 1997.

3. Measurements taken by the noise abatement officer for the Denver International Airport.

4. Regional Commission on Airport Affairs, Report on the Proposed Reduction in Noise Levels at the Seattle-Tacoma Airport, Prepared by Alice H. Suter, October 26,1994.

5. Puget Sound Regional Council; Final Decision of PSRC Experts Arbitration Panel on Phase II Noise Issues. March 29, 1996.

6. City of Chicago Department of Aviation, Monthly Airport Noise Report Summary, Chicago O'Hare International Airport, ; Reports for January through July 1997.

7. Natural Resources Defense Council, Flying Off Course, Environmental Impacts of America's Airports. October 1996.

8. Susan L. Staples. Human Response to Environmental Noise . American Psychologist, February 1996.

9. Editor Patricia J. Thompson, Interdisciplinary Perspectives; Impact of Noise on Health in Environmental Education for the 21st Century.

10. Business Week, Developments to Watch; Is it an Airplane or a Helicopter, or Both , Editor Peter Coy, May 27,1997.