This 2018 FAA memorandum explains how a special environmental review shortcut—called a Categorical Exclusion (CATEX 1)—can be used to streamline approval of certain GPS-based flight procedures (RNAV/RNP) at major airports, including core hub airports like Sea-Tac, without requiring a full environmental impact study. The exclusion applies unless officials determine that extraordinary circumstances exist that could cause significant environmental harm, such as notable noise impacts on surrounding communities. Specific documentation and approval from FAA environmental and legal offices are required before the exclusion can be applied.Open full document
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This FAA memorandum provides consolidated guidance for implementing a legislative categorical exclusion (CATEX 1) under Section 213(c)(1) of the FAA Modernization and Reform Act of 2012, which applies to RNAV/RNP air traffic procedures at core and non-core airports developed as part of NextGen. The memo clarifies documentation requirements, applicability criteria, extraordinary circumstances determinations, and compliance with other environmental laws before using CATEX 1.