US-CAW ACTIVITIES: 3/18/98 PRESS RELEASE
DATE: March 18, 1998 -- 9:30 a.m. (EST)
The question: What constitutes excessive aircraft noise and at what level does that noise cause psychological and physiological damage to people?
Re: The Federal Interagency on Aviation Noise (FICAN) held a forum: (1) to provide information on federal aviation noise projects, (2) to solicit input re: the direction of Federal researchers to share goals and results.
FICAN is an aviation noise research agency combined of the following US agencies: Depts. of Transportation-Federal Aviation Administration, Defense, Housing and Urban Development, National Aeronautics and Space Administration, Environmental Protection Agency & National Park Service.
US-CAW charges that:
(1) existing way of measuring aircraft noise is flawed; (2) the metric used (65DNL), is too high; (3) event measuring is flawed -- aircraft noise could be at least twice as loud; (4) method used to count affected people is grossly misrepresentative -- FAA states only 3.5 million people affected nationwide. Yet, in Illinois, from just one airport, Chicago O’Hare, the state conservatively estimates that 1.5 million people are affected.
Text of testimony to follow: Comments to FICAN Public Forum March 18, 1998 by US-Citizens Aviation Watch (US-CAW) And Citizens for the Abatement of Aircraft Noise (CAAN).
US-CAW and CAAN suggest four areas where FICAN can help alleviate the aircraft noise problem:
Area 1. Noise Metric: We will never resolve the noise issue until we can all agree on what the standards for noise measurement 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. high blood pressure, heart disease, and other health problems.
CAAN and US-CAW, as well as many others, believe that we need a new metric to measure noise because the DNL metric we are using is seriously flawed. Besides being set too high, the DNL metric has no relationship to what is really happening. If you are sleeping and one single DC-l0 flies over at 5000 feet, you will surely know it, but it will show only a small rise in the DNL for that day.
The new metric should include the effects of single noise events and health effects. Because we are learning that subsonic and ultra sonic waves can cause health problems. We should measure the full frequency noise spectrum rather than using the ‘A’ weighted scale (audible sound). We recommend that a panel, independent from the FAA and the airline industry, be convened to design this new metric.
Area 2. Noise Algorithm: The algorithm used to measure noise masks the true nature of aircraft noise by attributing any noise not considered aircraft noise to the community. The fault lies in the fact that the 10 second sample time for determining if a noise event is an aircraft, does not consider the possibility that a reflected wave arriving at the noise monitoring microphone can suppress the signal below the threshold for a few microseconds, thereby negating an aircraft report. When this drop-out occurs, the noise event is charged to community noise. CAAN has data that show that the community noise level for one local monitoring station is actually 15 dB lower than what the local Airports Authority is reporting. Other monitoring stations may show a similar pattern. Conversely, it means that the reported aircraft DNL is higher than what is presently being reported, and may drive more monitoring stations over 65 DNL, the value which the FAA has established as the limit for residential living. The algorithm needs to be changed to correct this deficiency.
Area 3. Noise Statistics: We are being told that fewer people are being impacted by aircraft noise. CAAN and US-CAW and many other citizens' groups around the country disagree. The 3.5 million people cited by the FAA's Mr. Erickson in his October 21st testimony to the House Subcommittee on Technology plainly uses a very restrictive definition which seems to have little to do with reality. Therefore, we suggest that FICAN reexamine the method used to arrive at this number.
Area 4. Helicopter Noise: Noise from helicopters in a metropolitan area is another serious problem. They usually fly low, often under five hundred feet. They rattle windows and knock pictures off the wall indicating that there is a strong low and subsonic frequency component to this type of noise. Citizen groups in California recently requested that 1000 feet AGL be established as a minimum altitude for transiting helicopters, but FAA has twice rejected that request. We believe that this was a bad decision. The root cause, though, is that little emphasis has been put on reducing noise from helicopters. To improve this situation, we urge that more research dollars be expended in this area of noise reduction.
D.W. MacGlashan for Citizens for the Abatement of Aircraft Noise
US-Citizens Aviation Watch