; and (2) construction of noise barriers or acoustic shielding to mitigate ground-level noise. (d) Instrumentation Upon request of a designated community, and in addition to the annualized average measurement, the Administrator shall provide additional noise measurement instrumentation to measure airplane noise. (e) Sound insulation for aviation-Impacted communities The Administrator of the Federal Aviation Administration and airport operators may provide sound insulation for aviation-impacted communities that are subjected to substantial increases in flight frequency or from the adoption of new flight procedures that create noise impacts in neighborhoods that did not previously experience significant impacts from commercial aircraft operations. (f) Sound insulation for neighborhoods The Administrator of the Federal Aviation Administration and airport operators may provide sound insulation for neighborhoods within a 55 DNL contour in which an airport operator or the Administrator of the Federal Aviation Administration determines significant numbers of flight operations are conducted between 10:00 p.m. and 6:00 a.m. 6. Authorization of appropriations There are authorized to be appropriated to carry out this Act such sums as may be necessary. 7. Definitions In this Act: (1) The term Administrator means the Administrator of the Federal Aviation Administration. (2) The term aviation-impacted community means a community that is located not greater than 1 mile from any point at which a commercial or cargo jet route is 3,000 feet or less above ground level. (3) The term community means any residential neighborhood, locality, municipality, town, or city. (4) The term designated community means an aviation-impacted community that has chosen to be designated pursuant to section 1. (5) The term disparate impact means noise, air pollution emissions, or any other aviation-related impact identified by a community coming from a commercial or cargo jet route and that is affecting a community or its residents.