14 C.F.R. § 34.23

Current through September 30, 2024

Section 34.23 - Exhaust Emission Standards for Engines Manufactured on and after July 18, 2012

The standards of this section apply to aircraft engines manufactured on and after July 18, 2012, unless otherwise exempted or excepted. Where a gaseous emission standard is specified by a formula, calculate and round the standard to three significant figures or to the nearest 0.1 g/kN (for standards at or above 100 g/kN). Where a smoke standard is specified by a formula, calculate and round the standard to the nearest 0.1 SN. Engines comply with an applicable standard if the testing results show that the engine type certificate family's characteristic level does not exceed the numerical level of that standard, as described in § 34.60 .

(a) Gaseous exhaust emissions from each new aircraft gas turbine engine shall not exceed:

(1) [Reserved]

(2) Except as provided in §§ 34.9(b) and 34.21(c) , for Classes TF, T3 and T8 engines manufactured on and after July 18, 2012, and for which the first individual production model was manufactured on or before December 31, 2013 (Tier 6):

Tier 6 Oxides of Nitrogen Emission Standards for Subsonic Engines

Class	Rated pressure ratio-rPR	Rated output rO (kN)	NO_X (g/kN)
TF, T3, T8	rPR [LESS THAN EQUAL TO] 30	26.7 [LESS THAN] rO [LESS THAN EQUAL TO] 89.0	38.5486 + 1.6823 (rPR) - 0.2453 (rO) - (0.00308 (rPR) (rO)).
		rO [GREATER THAN] 89.0	16.72 + 1.4080 (rPR).
	30 [LESS THAN] rPR [LESS THAN] 82.6	26.7 [LESS THAN] rO [LESS THAN EQUAL TO] 89.0	46.1600 + 1.4286 (rPR) - 0.5303 (rO) + (0.00642 (rPR) (rO)).
		rO [GREATER THAN] 89.0	-1.04 + 2.0 (rPR).
	rPR [GREATER THAN EQUAL TO] 82.6	rO [GREATER THAN EQUAL TO] 26.7	32 + 1.6 (rPR).

(3) Engines exempted from paragraph (a)(2) of this section produced on or before December 31, 2016 must be labeled "EXEMPT NEW" in accordance with § 45.13 of this chapter. No exemptions to the requirements of paragraph (a)(2) of this section will be granted after December 31, 2016.

(4) For Class TSS Engines manufactured on and after July 18, 2012:

Gaseous Emission Standards for Supersonic Engines

Class	Rated output rO¹ (kN)	NO_X (g/kN)	CO (g/kN)
TSS	All	36 + 2.42 (rPR)	4,550 (rPR)^-1.03

¹ rO is the rated output with afterburning applied.

(b) Gaseous exhaust emissions from each new aircraft gas turbine engine shall not exceed:

(1) For Classes TF, T3 and T8 engines of a type or model of which the first individual production model was manufactured after December 31, 2013 (Tier 8):

Tier 8 Oxides of Nitrogen Emission Standards for Subsonic Engines

Class	Rated pressure ratio-rPR	Rated output rO (kN)	NO_X (g/kN)
TF, T3, T8	rPR [LESS THAN EQUAL TO] 30	26.7 [LESS THAN] rO [LESS THAN EQUAL TO] 89.0	40.052 + 1.5681 (rPR) - 0.3615 (rO) - (0.0018 (rPR) (rO)).
		rO [GREATER THAN] 89.0	7.88 + 1.4080 (rPR).
	30 [LESS THAN] rPR [LESS THAN] 104.7	26.7 [LESS THAN] rO [LESS THAN EQUAL TO] 89.0	41.9435 + 1.505 (rPR) - 0.5823 (rO) + (0.005562 (rPR) (rO)).
		rO [GREATER THAN] 89.0	-9.88 + 2.0 (rPR).
	rPR [GREATER THAN EQUAL TO] 104.7	rO [GREATER THAN EQUAL TO] 26.7	32 + 1.6 (rPR).

(c) Engines (including engines that are determined to be derivative engines for the purposes of emission certification) type certificated with characteristic levels at or below the NO_X standards of § 34.21(d)(1)(vi) of this part (as applicable based on rated output and rated pressure ratio) and introduced before July 18, 2012, may be produced through December 31, 2012, without meeting the NO_X standard of paragraph (a)(2) of this section.

14 C.F.R. §34.23

Doc. No. 34-5, 77 FR 76851, Dec. 31, 2012, as amended by Amdt. 34-5A, 78 FR 63017, Oct. 23, 2013; 78 FR 65554, Nov. 1, 2013

89 FR 31087, 5/24/2024