; (3) the risks of such reclassification on navigation aid equipment currently in use; (4) the potential impacts on global interoperability of navigational aids; and (5) what additional actions should be taken based on the findings of this subsection. (c) Report Not later than 24 months after the date of enactment of this Act, the inspector general shall submit to the appropriate committees of Congress a report describing the results of the study conducted under subsection (a). 603. NextGen accountability review (a) In general Not later than December 31, 2026, the Administrator shall seek to enter into an agreement with the National Academy of Public Administration to initiate a review to assess the performance of the FAA in delivering and implementing quantifiable operational benefits to the national airspace system within the NextGen program. (b) Review requirements In conducting the review required under subsection (a), the National Academy of Public Administration shall— (1) leverage metrics used by the FAA to quantify the benefits of NextGen technology and investments; (2) validate metrics and identify additional metrics the FAA can use to track national airspace system throughput and savings as a result of NextGen investments— (A) by calculating a per flight average, weighted by distance, of the— (i) reduction and cumulative savings of track miles and time savings; (ii) reduction and cumulative savings of emissions and fuel burn; and (iii) reduction of aircraft operation time; and (B) by using any other metrics that the National Academy determines may provide insights into the quantifiable benefits for operators in the national airspace system