On July 6, the Environmental Protection Agency (“EPA”) released a proposed rule to set nitrogen oxide (NOx) emissions standards for aircraft engines in line with those already endorsed by the United Nations’ International Civil Aviation Organization (“ICAO”). The Air Transport Association (“ATA”) asserted that it would ensure the rule was in harmony with international standards. The proposed rule would apply to engines with thrusts greater than 26.7 kilonewtons, usually found in commercial passenger and freight aircraft, and would reduce ground-level nitrogen oxide emissions in the United States by 100,000 tons between 2014 and 2030.

The proposed rule would set two stringent emissions tiers for nitrogen oxide, called “Tier 6” and “Tier 8.” Aircraft engine models certified before the effective date of the proposed rule can continue production through December 31, 2012. Engine models certified between the effective date and December 31, 2013 will have to adhere to the Tier 6 emissions standard. The Tier 8 standard will be mandatory for engine models certified on or after January 1, 2014. An equivalent Tier 6 standard became effective internationally in December 2007 and an equivalent Tier 8 standard was recommended to the ICAO in February 2010. The proposed rule would take effect only if the ICAO adopts equivalent standards. If the ICAO adopts different standards, however, EPA will reevaluate accordingly. 

More information on the proposed rule is available on EPA’s website. The proposed rule will be open to public comment for 60 days from the date of publication in the Federal Register. Corporate aircraft owners should take this opportunity to voice concerns and questions in the event that EPA decides to take similar regulatory action on smaller aircraft engines. As this issue progresses, please check back to this blog for future posts.