Comment submitted by Dominique Reneric, Dassault-Aviation

Dassault- Aviation appreciates the opportunity to review EPA draft and would like these following comments to be considered: The proposed modifications in §87.23« Exhaust emission standards for Tier 6 and 8 engines” and §87.48 “Derivative engines for emissions certification purposes “ imply that if an engine modification occurs after January 1, 2014 and it is not considered as an engine derivative (per criteria (2) (b) (1)), the applicant will have to comply with the latest Tier 8 NOx standard regardless if the modification decreases the current NOx characteristics levels. The ETM Vol II Doc 9501 recommends to “retain the existing certification basis of the parent engine if the modification(s) : … b) results in a decrease of the absolute emissions levels; …” Therefore, the proposed text is more stringent than the ETM Vol II. Such recommendation could have a negative environmental impact as some technology improvement might not be implemented on in-production engine because they do not allow to meet CAEP 8 standard. Moreover, it does not allow to maintain consistency with other standard such as EASA that proposed in NPA2011-08 to incorporate the ETM text on the applicable requirement of such engine modification. Finally, the cost impact and emission “benefit/penalty” of such proposal has not been evaluated within the CAEP6 and CAEP8 process. Dassault-Aviation recommends to maintain consistency with the proposed ETM Vol II Doc 9501.