This FAA guidance document explains how to analyze cumulative environmental impacts for aviation projects, meaning the combined effect of an airport action together with other past, present, and foreseeable future actions by any agency or party. It outlines how to define the study area, determine significance, and consider mitigation, noting that even individually minor impacts can together become significant. While focused on FAA projects broadly, it is relevant to noise and environmental planning at airports like Sea-Tac, where surrounding development and multiple simultaneous projects can compound environmental effects.Open full document
Notes
This chapter from the FAA’s 1050.1F Desk Reference provides guidance on analyzing cumulative impacts under NEPA, defining them as the total combined environmental effects of a proposed action added to past, present, and reasonably foreseeable future actions. It covers how to identify relevant actions, define the study area, determine significance, consider mitigation, and present analysis results in NEPA documents.