The U.S. Environmental Protection Agency (EPA) has issued a final rule setting aircraft engine emissions standards for oxides of nitrogen (NOX ) from certain gas turbo engines used by commercial aircraft. 77 Fed. Reg. 36,341 (6/18/12). The new standards apply to commercial and freight aircraft with thrusts greater than 26.7 kilonewtons. The standards have already been adopted by the International Civil Aviation Organization.
The rule would set two tiers of NOX emission standards. The first would apply to engine models manufactured and certified before July 18, 2012; these models would have until December 31, 2013, to comply with Tier 6 standards, which would result in a 12-percent reduction from the current Tier 4 standards. The second tier, or Tier 8 standards, would result in a 15-percent reduction from Tier 6 emission levels. These standards apply to aircraft engine models certified on or after January 1, 2014. The rule is effective July 18, 2012.