; and (F) such other stakeholders and aviation experts as the Comptroller General considers appropriate. (c) Report Not later than 18 months after the date of enactment of this Act, the Comptroller General shall submit to the appropriate committees of Congress a report on the results of the review. (d) Covered stage 3 aircraft defined In this section, the term covered stage 3 aircraft means a civil subsonic jet aircraft that is not capable of meeting the stage 4 noise levels in part 36 of title 14, Code of Federal Regulations. 187. Aircraft noise exposure (a) Review The Administrator of the Federal Aviation Administration shall conclude the Administrator’s ongoing review of the relationship between aircraft noise exposure and its effects on communities around airports. (b) Report (1) In general Not later than 2 years after the date of enactment of this Act, the Administrator shall submit to Congress a report containing the results of the review. (2) Preliminary recommendations The report shall contain such preliminary recommendations as the Administrator determines appropriate for revising the land use compatibility guidelines in part 150 of title 14, Code of Federal Regulations, based on the results of the review and in coordination with other agencies. 188. Study regarding day-night average sound levels (a) Study The Administrator of the Federal Aviation Administration shall evaluate alternative metrics to the current average day-night level standard, such as the use of actual noise sampling and other methods, to address community airplane noise concerns. (b) Report Not later than 1 year after the date of enactment of this Act, the Administrator shall submit to the appropriate committees of Congress a report on the results of the study under subsection (a). 189. Study on potential health and economic impacts of overflight noise (a) In general Not later than 180 days after the date of enactment of this Act, the Administrator of the Federal Aviation Administration shall enter into an agreement with an eligible