; or (2) the date on which 1 briefing is provided under subsection (c) after the changes in subsection (a) are implemented. 787. Reducing community aircraft noise exposure In implementing or substantially revising a flight procedure, the Administrator shall consider the following actions (to the extent that such actions do not negatively affect aviation safety or efficiency) to reduce undesirable aircraft noise: (1) Implement flight procedures that can mitigate the impact of aircraft noise, based on a consensus community recommendation. (2) Work with airport sponsors and potentially impacted neighboring communities in establishing or modifying aircraft arrival and departure routes. (3) In collaboration with local governments, discourage local encroachment of residential or other buildings near airports that could create future aircraft noise complaints or impact airport operations or aviation safety. 788. Categorical exclusions (a) Categorical exclusion for projects of limited Federal assistance An action by the Administrator to approve, permit, finance, or otherwise authorize any airport project that is undertaken by the sponsor, owner, or operator of a public-use airport shall be presumed to be covered by a categorical exclusion under FAA Order 1050.1F (or any successor document), if such project— (1) receives less than $6,000,000 (as adjusted annually by the Administrator to reflect any increases in the Consumer Price Index prepared by the Department of Labor) of Federal funds or funds from charges collected under section 40117 of title 49, United States Code