TagCATEX(16)

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.

This document presents a community challenge to the FAA's environmental review (CATEX) of new flight routes near Seattle-Tacoma International Airport, arguing that the FAA's own noise analyses show significant noise increases in the surrounding General Study Area that exceed the agency's own significance thresholds. The authors contend that the FAA could not rely on the outdated 2013-2018 Port of Seattle Part 150 noise study, and that the FAA's independent analyses revealed noise level jumps ranging from 5.2% to nearly 60% across various decibel contours. The document concludes that the FAA's declaration of 'no noise impacts' is implausible given data showing that portions of previously quiet neighborhoods now experience non-compatible land use noise levels above 65 dB DNL.

In April 2018, the FAA issued a Categorical Exclusion allowing Seattle-Tacoma International Airport's control tower (SEA ATCT) to automatically direct southbound turboprop aircraft to turn westward to a 250-degree heading within one nautical mile of the runway end, rather than waiting for the Seattle TRACON radar facility to issue the turn after takeoff. This procedural change, active between 6 am and 10 pm during north-flow operations, was designed to improve safety and efficiency by reducing delays in aircraft transitioning to their filed flight routes. The FAA determined the action would not significantly increase noise over sensitive areas and therefore required no further environmental review beyond this Categorical Exclusion.