Two-thirds of the more than 350 comments submitted to the U.S. Environmental Protection Agency’s (EPA) proposed rule to control and set standards for turbine airplane emissions said the intended rule falls far short of what it should be and that it should be more stringent. Meanwhile, about a third are generally satisfied with the proposal as written and intended.

In addition to some 50 individuals, comments were submitted by trade groups, associations, and NGOs representing primarily aircraft operators, airframe manufacturers, and environmental interests.

The proposal, published on July 20 with a comment period that closed on October 19, is intended to bring emissions standards and test procedures in line with those of the International Civil Aviation Organization (ICAO). Critics want a rule that actually reduces greenhouse gas (GHG) emissions. As one environmental organization put it: “This proposed rule is meant solely to comply with the minimum standards set by ICAO with no foreseeable reduction in emissions that can be attributed to the proposed rule.”

Voicing the view of many industry commenters, business and commercial aircraft manufacturer Embraer said the EPA should “replace the currently proposed rule with one that: applies to in-service aircraft, not just to new aircraft and new aircraft designs; include the emissions reductions achievable through both airframe design and operational improvements; and include a ratchet mechanism to decrease emissions over time and fully decarbonize the industry by 2045 or sooner.”

NBAA noted in its comments an international program to significantly reduce business aviation’s harmful emissions over the next 30 years.                                          

Other commenters criticized the proposal for not recognizing the successes made in the use of sustainable aviation fuel (SAF). For example, this from Shell Oil: “By setting more challenging, yet achievable, mandates, EPA can create an environment for investment that can support additional production and use of SAF to help the aviation sector reduce emissions.”

Several aicraft manufacturers and associations, including NBAA, protested the proposed annual reporting requirement as requested. The NPRM requires that all civil aircraft manufacturers worldwide submit their respective volume and rate of specific aircraft models produced in the previous year.

Said Bombardier: “Like all business aircraft manufacturers, Bombardier Aviation considers its annual production rate as confidential information, proprietary to the company. Regardless, Bombardier currently reports its aircraft deliveries on a quarterly basis to several public and industry organizations. Bombardier requests that this publicly available aircraft delivery information be considered by the EPA for usage in its technical assessments, as an alternative.”

EPA Justifies Less Stringent Proposal

The EPA believes that by aligning U.S. standards with those from ICAO, rather than adopting more stringent standards, the rule “will have substantial benefits for future international cooperation on airplane emission standards, and such cooperation is the key for achieving worldwide emission reductions.”

Nonetheless, the EPA also analyzed the impact of two more-stringent regulatory alternatives but concluded that the additional emission reductions associated with those alternatives “are relatively small.”

In addition, “requiring U.S. manufacturers to certify to a different standard than has been adopted internationally (even one more stringent) could have disruptive effects on manufacturers’ ability to market planes for international operation,” the EPA said. Engine manufacturer General Electric agreed: “These (EPA) analyses show that the alternatives would lead to minimal reduction in [greenhouse gas] emissions, while imposing significant costs associated with deviating from the ICAO standards. Consequently, EPA appropriately decided against proposing either of these alternatives.”

The General Aviation Manufacturers Association (GAMA) supports the proposed standards. However, GAMA said it has "serious concerns" about requiring manufacturers to report information that is already publicly available, "as well as information that ICAO does not request, such as RGF [a measure of fuselage size] and production volumes for airplane submodels."

Finally, aircraft manufacturers and operators alike said the EPA should clarify that the final rule applies only to “civil aircraft” and that public, military, government, and special missions aircraft are outside the scope of the standard.