BBN Systems and Technologies, 21120 Vanowen St., Canoga Park, CA 91303
As quieter aircraft have begun to replace some of the noiser ones in the civil air transport fleet, aircraft noise exposure levels in certain airport neighborhoods have declined to some degree. Federal agencies with interests in aviation noise have not yet offered policy guidance for gauging the smallest decrease in aircraft noise that may be considered meaningful under these circumstances in airport neighborhoods. An empirical study of this issue was thus underken in residential areas near a large airport at which noise exposure levels had declined by several decibels over the last few years. Very few neighborhood residents either noticed a decrease in aircraft noise in the recent past or decribed themselves as less annoyed by aircraft noise than in prior years.