The Office of Management and Budget has approved funding for the FAA’s Neighborhood Environmental Survey to determine the viability of the Day-Night Average Sound Level (DNL) 65 dB noise metric. In 2008, ONCC requested that the FAA initiate research to determine the appropriateness of the continued use of DNL 65 dB metric as the standard for sound insulation eligibility. The FAA hopes to complete the survey by late 2016. Read more