755 

Federal Aviation Administration, DOT 

§ 34.60 

Subpart E—Certification Provisions 

§ 34.48

Derivative engines for emis-

sions certification purposes. 

(a) 

General.  A derivative engine for 

emissions certification purposes is an 
engine configuration that is deter-
mined to be similar in design to a pre-
viously certificated (original) engine 
for purposes of compliance with ex-
haust emissions standards (gaseous and 
smoke). A type certificate holder may 
request from the FAA a determination 
that an engine configuration is consid-
ered a derivative engine for emissions 
certification purposes. To be consid-
ered a derivative engine for emission 
purposes under this part, the configu-
ration must have been derived from the 
original engine that was certificated to 
the requirements of part 33 of this 
chapter and one of the following: 

(1) The FAA has determined that a 

safety issue exists that requires an en-
gine modification. 

(2) Emissions from the derivative en-

gines are determined to be similar. In 
general, this means the emissions must 
meet the criteria specified in para-
graph (b) of this section. The FAA may 
amend the criteria of paragraph (b) in 
unusual circumstances, for individual 
cases, consistent with good engineering 
judgment. 

(3) All of the regulated emissions 

from the derivative engine are lower 
than the original engine. 

(b) 

Emissions similarity. (1) The type 

certificate holder must demonstrate 
that the proposed derivative engine 
model’s emissions meet the applicable 
standards and differ from the original 
model’s emission rates only within the 
following ranges: 

(i) 

±

3.0 g/kN for NO

X

. 

(ii) 

±

1.0 g/kN for HC. 

(iii) 

±

5.0 g/kN for CO. 

(iv) 

±

2.0 SN for smoke. 

(2) If the characteristic level of the 

original certificated engine model (or 
any other sub-models within the emis-
sion type certificate family tested for 
certification) before modification is at 
or above 95% of the applicable standard 
for any pollutant, an applicant must 
measure the proposed derivative engine 
model’s emissions for all pollutants to 
demonstrate that the derivative en-
gine’s resulting characteristic levels 

will not exceed the applicable emission 
standards. If the characteristic levels 
of the originally certificated engine 
model (and all other sub-models within 
the emission type certificate family 
tested for certification) are below 95% 
of the applicable standard for each pol-
lutant, the applicant may use engineer-
ing analysis consistent with good engi-
neering judgment to demonstrate that 
the derivative engine will not exceed 
the applicable emission standards. The 
engineering analysis must address all 
modifications from the original engine, 
including those approved for previous 
derivative engines. 

(c) 

Continued production allowance. 

Derivative engines for emissions cer-
tification purposes may continue to be 
produced after the applicability date 
for new emissions standards when the 
engines conform to the specifications 
of this section. 

(d) 

Non-derivative engines. If the FAA 

determines that an engine model does 
not meet the requirements for a deriva-
tive engine for emissions certification 
purposes, the type certificate holder is 
required to demonstrate that the en-
gine complies with the emissions 
standards applicable to a new engine 
type. 

[Doc. No. 34–5, 77 FR 76852, Dec. 31, 2012] 

Subpart F 

[

Reserved

] 

Subpart G—Test Procedures for 

Engine Exhaust Gaseous Emis-
sions (Aircraft and Aircraft 
Gas Turbine Engines) 

§ 34.60

Introduction. 

(a) Use the equipment and procedures 

specified in Appendix 3, Appendix 5, 
and Appendix 6 of ICAO Annex 16, as 
applicable, to demonstrate whether en-
gines meet the applicable gaseous 
emission standards specified in subpart 
C of this part. Measure the emissions of 
all regulated gaseous pollutants. Use 
the equipment and procedures specified 
in Appendix 2 and Appendix 6 of ICAO 
Annex 16 to determine whether engines 
meet the applicable smoke standard 
specified in subpart C of this part. The 
compliance demonstration consists of 
establishing a mean value from testing 
the specified number of engines, then 

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