UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

National Vehicle and Fuel Emissions Laboratory

2000 Traverwood Drive

Ann Arbor, Michigan 48105-2498

March 27, 2012

MEMORANDUM

SUBJECT: Discussion with General Electric Regarding the Leadtime Associated the

Proposed Aircraft Engine Tier 6 NOx Production Cutoff—January 4, 2012

FROM: Richard S. Wilcox, Environmental Scientist

Assessment and Standards Division

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

TO: The Air and Radiation Docket

Docket No. EPA-HQ-OAR-2010-0687

We held a conference call on January 4, 2012 to continue discussing a public comment 

submitted by General Electric (GE) on our Notice of Proposed Rulemaking for new aircraft 

engine NOx emission standards and other requirements (July 27, 2011, 76 FR 45012). 

Specifically, GE expressed a concern that there may be inadequate leadtime for the FAA to 

formally recognize Tier 6 compliance for the numerous engine models before the January 1, 

2013 effective date of the Tier 6 NOx production cutoff.1 Attending the conference call for EPA 

were Glenn Passavant and myself. Attending for the FAA was Ralph Lovinelli. Attending for GE 

was Will Dodds.

The purpose of the call was to provide an opportunity for the FAA to explain a process 

they were developing to ensure that all engines requiring a formal recognition of compliance 

with the Tier 6 standards would receive such an acknowledgement for the FAA without affecting 

normal engine production schedules after the January 1, 2013 cutoff date. In advance of the 

discussion, GE provided a list of questions via email. A copy of this email is attached.

The FAA generally described a process that would begin after EPA’s final rule, and 

conclude with either a letter to the engine manufacturer certifying an engine model as Tier 6 or 

 

1 U.S. EPA, “Discussion with General Electric Regarding the Leadtime Associated with EPA’s Final Aircraft 

Engine NOx Rule and the Proposed Tier 6 Production Cutoff—January 3, 2012 ,” memorandum from Richard S. 

Wilcox, Assessment and Standards Division, Office of Transportation and Air Quality, to docket EPA-HQ-OAR2010-0687, March 27, 2012.
 

Tier 8 compliant based on existing certification reports, or a modification to the engine model’s 

type certificate datasheet base on the same information. GE requested that the FAA initiate the 

process prior to EPA’s final rule to maximize the available leadtime to take the necessary action.

attachment
 

attachment

From: "Dodds, Willard (GE Aviation, US)" <willard.dodds@ge.com>

To: Rich Wilcox/AA/USEPA/US@EPA

Date: 01/04/2012 01:17 PM

Subject: Questions on Tier6 certification procedures

Rich,

These are a few of the questions I have. It might be useful to get the manufacturers together to make 

sure all the issues are covered.

I don’t think this should really be a big deal, but if time is short, we should be prepared to complete the 

process quickly.

Will the Engine Cert Data Sheets be updated to show compliance?

Can we show compliance with both Tier 6 and Tier 8 at the same time?

Will we have to try to correct for current measurement procedures (e.g. nitrogen vs. air zero gases)? 

Will we have to update for current calculation procedures (e.g. revised standard humidity)? 

Will this just process just focus on NOx, and “grandfather” CO, HC and smoke?

Will there be a “standard” report format. Will a letter referring to the original report be sufficient?

When can we start the process? Do we have to wait until FAR par 34 is amended?

Thanks,

Will