William M. Monroe's letter (April 9) regarding the regular violation of noise abatement regulations at John Wayne Airport contains factual errors that need to be corrected.
The impact of aircraft noise is a subject of considerable concern to the Board of Supervisors and to airport management. John Wayne Airport has established one of the most comprehensive and effective noise-abatement programs in the country. It is staffed by five full-time personnel who monitor noise levels for commercial and general aviation operations--as well as numerous other controls and restrictions dictated by the 1985 settlement agreement and the airport's commercial airline access plan.
Contrary to Monroe's letter, we have excellent compliance with our noise regulations. Commercial operators must operate with a quarterly SENEL average (a noise metric equivalent to a constant sound level lasting for one second) of between 86 to 100 dB SENEL, depending upon the type of aircraft. Because each airline's operating agreement contains a provision that allows the airport manager to expel the carrier for violating noise regulations, the airlines are diligent about monitoring their noise levels and quarterly compliance to protect and maintain their presence in Orange County.
The county's general aviation noise ordinance regulates noise levels for small planes and private jets on a single-incident basis. General aviation aircraft are subject to the same limits as commercial flights during regular operating hours but must produce noise levels of less than 86 dB SENEL if they fly during curfew hours. We have viewed the ordinance as an educational process for general aviation pilots, and they too have been extremely cooperative. In fact, for the most recent 6-month reporting period (June, 1988, through December, 1988) noise violations represent only 0.057% of the 225,803 total operations.