On July 5, 2005, the FAA issued a final rule establishing a Stage 4 noise standard.  After January 1, 2006, all applications for new aircraft designs must demonstrate compliance with Stage 4 noise levels.  Stage 4 represents a 10 decibel reduction from Stage 3; however, this is a cumulative reduction over the three different phases of flight testing (fly-over, lateral and approach).  Many aircraft manufactured today can meet Stage 4 with little or no adjustment.  The FAA’s imposition of Stage 4 is consistent with international efforts by the International Civil Aviation Organization (ICAO).