On June 18, 2012, the Environmental Protection Agency (“EPA”) posted in the Federal Register, Vol. 77, No. 117, 36342, its Final Rule adopting several new aircraft engine emission standards for oxides of nitrogen (“NOx”) for aircraft turbofan or turbojet engines with rated thrusts greater than 26.7 kilonewtons (kN), or in common parlance, commercial passenger and freighter aircraft normally used at airports across the United States.  The rule applies only to the manufacture of new aircraft engines, not to retrofit of existing aircraft engines. 

The EPA’s stated purpose in enacting the new rule is two-fold.  First, NOx is strongly correlated with nitrogen dioxide (“NO2”) which is a “criteria pollutant” under the EPA’s National Ambient Air Quality Standards (“NAAQS”), and is an important precursor gas in the formation of ozone and secondary particulate matter (“PM2.5”) which are common air pollutants in urban areas where airports are often located.  Second, the new rule will bring United States’ emissions standards into consistency with those established by the International Civil Aviation Organization (“ICAO”), see ICAO Annex 16, Vol. II, 2010 that the U.S. helped to develop and supports as part of the international process. 

The rule contains six major provisions.

The first two provisions involve new NOx emissions standards for newly certified-engine models.  The first standard, Tier 6, which takes effect when the rule becomes effective, represents approximately a 12% reduction from current levels.  The second standard, Tier 8, takes effect in 2014, and represents approximately a 15% reduction from current levels.  The third major provision is a production cutoff for newly manufactured engines (as opposed to newly certified engines) which basically requires that after December 31, 2012, all newly manufactured engines must meet at least Tier 6 NOx emissions standards.  (EPA opines that the production cutoff is needed to ensure that the emissions reductions envisioned by the emissions standards are achieved on new production engines.)  The fourth major provision is related to potential exemptions or exceptions to the production cutoff requirement, including provisions allowing manufacturers to request that the Federal Aviation Administration (“FAA”), in consultation with EPA, grant exemptions from the production cutoff for a designated number of engines within a prescribed timeframe.  The sixth and final set of provisions address such matters as spare engines, derivative engine models, test procedure specifications and reporting requirements. 

EPA’s authority to make these changes is not independent of the authority of other agencies.  The Clean Air Act, 42 U.S.C. § 7571(a)(2)(A), while allowing the EPA Administrator to propose aircraft engine emissions standards applicable to the emission of any air pollutant which, in his/her judgment causes or contributes to pollution that may endanger public health or welfare, also directs EPA to consult with the Administrator of the FAA on such standards, 42 U.S.C. § 7571(a)(2)(B), and prohibits EPA from changing aircraft emissions standards if such a change would significantly increase noise and adversely affect safety, 42 U.S.C. § 7571(a)(2)(B)(i)-(ii).  In a recent case, the U.S. Court of Appeals for the D.C. Circuit held that these provisions confer an unusually broad degree of discretion on EPA to adopt such aircraft engine emissions standards as the agency determines are reasonable.  NACAA v. EPA, 489 F.3d 1221 (D.C. Cir. 2007). 

While the new rule originally caused some consternation among aircraft manufacturers, EPA is relying on the fact that engine manufacturers participated in the deliberations leading up to aircraft engine NOx emissions standards adopted by ICAO, and after the adoption of those standards, incorporated engine technology changes into their products as needed to meet those standards, thus ensuring the worldwide acceptability of their products.  As all the required production changes are now complete, there will be no further significant direct cost to manufacturers created by EPA’s adoption of the previous ICAO requirements into new U.S. regulations.  The apparent goal of these regulations is eventual reductions in some of the most pervasive emissions suffered by communities around airports, as well as in ozone precursors and, thus, the greenhouse gases to which they are a significant contributor.  The Final Rule will become effective on July 18, 2012.