A three-year study of noise problems at Burbank Airport is inching toward a conclusion that not much more can be done to reduce aircraft noise, and the federal government should pay the airport's closest neighbors to soundproof their homes or move.
The study, a complex affair, has been further complicated by becoming entangled in the bitter political struggle between the Burbank-Glendale-Pasadena Airport Authority and Los Angeles officeholders who represent neighborhood anti-noise groups in the eastern San Fernando Valley.
Begun in July, 1985, and involving two committees with 68 members and a consulting firm, the study still faces two major hurdles: a vote by the nine-member airport authority, expected in September, and a review by the Federal Aviation Administration. The FAA, expected to complete its review next spring, is free to reject any or all of the study's recommendations.
The study has cost about $450,000, 60% paid by a federal grant, Burbank Airport officials said, mostly for computer modeling studies showing the noise impact of the expected growth in the airport's traffic load by the year 2000.
Central to the political battle are the airport authority's plans to build a new terminal and the demands of noise protesters and Los Angeles officeholders that the authority try to persuade airline pilots to "share the noise" by taking off at least half the time over the Burbank and Glendale areas east of the airport.
The FAA sponsors the study, which has been carried out at Los Angeles International, Long Beach and other airports throughout the country and is known as a Part 150 study after the FAA regulation that establishes the procedure.
Critics say the process is weighted against them and that FAA and airport administrators establish rules and technical presumptions that guide the study in the direction they wish--toward more air traffic and the soundproofing or elimination of nearby homes.
Airport administrators say the study committees include virtually anyone with an interest in the subject, from local government to neighborhood groups.
Critics counter that the inclusion of so many people with such a variety of conflicting goals and attitudes, guarantees there will be delays, confusion and many long, divisive meetings that eventually wear out citizen activists.
"It's a stalling technique that airports use to buy anywhere from two to five years' time," said Gerald Silver, president of Homeowners of Encino and a leader for years of efforts against aircraft noise in the San Fernando Valley.
Silver, who argues that all jet air traffic should be banished from the San Fernando Valley to airports in the Mojave Desert, said he rejects Part 150 studies as flawed from the start because they do not try to limit the number of aircraft using an airport and because of the method used to measure noise.
The basic measurement of Part 150 studies is the CNEL--Community Noise Equivalent Level. It is based on decibel readings of noise recorded by 15 listening stations around the airport. The readings are averaged, using a formula reflecting that noise is more annoying at night. The daily averages are averaged into a quarterly reading.
The quarterly readings are used in mapping lines around the airport, creating noise zones called "footprints." The "65 CNEL footprint," for example, encloses the area in which all the average readings are 65 decibels or higher.
The footprint is an abstract statistical tool used for measuring noise that in the real world fluctuates from moment to moment. The real noise zone shrinks to nothing when there are no aircraft landing or taking off, and it expands far beyond the average-reading line when a heavily loaded jetliner is taking off under full power.
Called Valuable Tool
Supporters of the CNEL call it a valuable tool for reflecting the differences in noise burdens imposed on different areas, the only way to deal with a condition that changes by the second. Anti-noise critics say it is a meaningless measurement, arguing it should be replaced by a single event standard, such as a limit on the amount of noise one aircraft is allowed to make or on the number of aircraft operations allowed at an airport.
Since Burbank airport administrators have persuaded airlines to use the quietest aircraft available, the study concludes there is little help to be expected from the use of quieter engines.
The first draft of the study, by Peat Marwick, a consulting firm, suggested the airport administrators consider buying 54 homes within the 75 CNEL footprint projected for the year 2000. The homes are all in a small neighborhood just south of the airport.
If the suggestion is accepted, the airport will have to negotiate with the owners and discuss with Burbank city planners the impact of converting the land to non-residential use.