Global agreement on a market-based measure to curb aviation emissions is not the only possible environmental milestone of the upcoming ICAO Assembly in Montreal. Also on the cards is the final endorsement of the first-ever global carbon dioxide efficiency standard for aircraft, which was agreed and recommended in February by ICAO's Committee on Aviation Environmental Protection (CAEP).
The proposed standard will apply to new aircraft type-certificated after 1 January 2020, and also to today's in-production types from 2023 – but only if they undergo modifications that require recertification. ICAO has designated 2028 as the "cut-off date" for compliance by all remaining in-service aircraft.
All jet aircraft with a maximum certificated take-off weight of over 5.7t are covered by the measure, as are turboprops with a maximum certificated take-off weight of over 8.6t, and it spans the passenger, cargo and business aviation sectors.
An important question following the expected endorsement of this standard is whether the US Environmental Protection Agency (EPA) will decide to put forward a more stringent standard of its own to limit greenhouse gas (GHG) emissions from aircraft operating in the USA, or whether it will agree to adopt the proposed global standard in its current form.
In July, the EPA issued an endangerment finding which concluded that GHG emissions from certain classes of engines used in "US-covered aircraft" contribute to the air pollution that endangers public health and welfare. The EPA defines such aircraft as being subsonic jets with a maximum take-off mass (MTOM) greater than 5.7t and turboprops with a MTOM greater than 8.6t: a range which would go from the Cessna Citation CJ3+ business jet to the Airbus A380 superjumbo.
The EPA says it is "not at this time proposing or finalising aircraft engine GHG emissions standards", pointing out that it and the US Federal Aviation Administration "traditionally work within the standard-setting process of the CAEP to establish international emission standards and related requirements, which individual nations later adopt into domestic law".
Some groups, such as the International Council on Clean Transportation (ICCT), are keen to see the EPA draft an aircraft engine emissions standard of its own that goes a step beyond the standard proposed by ICAO.
"The endangerment finding is key because it obligates the EPA to take regulatory action to cut CO2 emissions from aircraft – it triggers a legal mandate," says ICCT executive director Drew Kodjak. "Our analysis clearly shows that the aircraft CO2 standard proposed by ICAO won't offer meaningful reductions. This opens a real possibility to get a better standard."
While the EPA is not at this time proposing a standard of its own, the agency points out that "aircraft remain the single-largest GHG-emitting transportation source not yet subject to GHG standards in the US". It goes on to say that US aircraft, including all domestic and international flights originating in the country, account for 12% of such emissions from the transportation sector there; 3% of total US GHG emissions, 29% of all global emissions, and 0.5% of total global GHG emissions.
The EPA says its endangerment finding does not prejudge what future EPA standards for engines used in covered aircraft could look like, but it will help to prepare for a future domestic rulemaking process to adopt a GHG standard.
"These findings trigger EPA's duty under the Clean Air Act to promulgate emissions standards applicable to GHG emissions from the classes of aircraft engines included in the contribution finding," says the agency. "Any such future proposed domestic regulatory actions would be open to the appropriate public comment and review, providing opportunity for stakeholders and the public to provide input."
Source: Flight International
