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Acoustical Acceptance Testing of Portland (Oregon) International Airport Ground Run-Up Enclosure

The Port of Portland constructed an aircraft ground run-up enclosure (GRE) at Portland International Airport (PDX) to allow unrestricted daytime and nighttime aircraft maintenance run-ups while complying with Oregon Department of Environmental Quality (DEQ) standards for community noise levels. To ensure compliance with the DEQ standards, a rigorous acoustical acceptance testing specification was developed and implemented. The PDX specification included measurements of three representative aircraft run-ups conducted at the GRE site (i.e., with GRE) and at a nearby equivalent site (i.e., without GRE). At each test site, measurements were required at six microphone locations at a reference distance of 400 ft (120 m) from the test aircraft, where variability in measured sound levels due to meteorological conditions would be limited. Although not part of the official acceptance test, simultaneous measurements were conducted in representative community locations as the start of ongoing community monitoring to be conducted by the Port of Portland. In April 2001, the GRE met the acoustical acceptance testing specifications and demonstrated compliance with the DEQ community requirements. The multiple-microphone arrays displayed the significant effect of noise shielding provided by aircraft fuselages and suggested that modifications may be appropriate for future applications of the test procedure.