§ 34.73 Demonstration of compliance for nvPM emissions. ( a ) Each compliance demonstration by an applicant requires: ( 1 ) Establishing a mean value from tests conducted on one or more engines;
( 2 ) Calculating a “characteristic level” by applying a set of statistical factors that take into account the number of engines tested in accordance with § 34.71(b) of this part; and
( 3 ) Rounding each characteristic level to the same number of decimal places as the corresponding emission limit.
( b ) In demonstrating compliance with this subpart, an applicant must use the nvPM measurements collected in accordance with § 34.71 as follows: ( 1 ) An engine complies with an applicable standard when the engine type certificate family's characteristic level does not exceed any nvPM limit described in § 34.25 of this part; and
( 2 ) A compliance demonstration consists of: ( i ) Determining the maximum nvPMMC, and the mean value for nvPMmass and nvPMnum from the data collected in accordance with paragraph § 34.71(f) of this part;
( ii ) Correcting each data point to standard temperature and pressure conditions;
( iii ) Applying the appropriate statistical factor shown in Table 6-1 of Appendix 6 of ICAO Annex 16, Volume II (incorporated by reference, see § 34.4) to account for the number of engines tested; and
( iv ) Rounding each characteristic level to the same number of decimal places as the corresponding nvPM limit in § 34.25 of this part.
( c ) ( 1 ) In determining maximum nvPMMC, an applicant must use one of the following evaluation methods for all engines measured in accordance with § 34.71(c) of this par and using the thrust settings given in § 34.71(h) of this part. An applicant may choose to measure additional thrust settings; while there is no restriction on the number of thrust settings measured, the same thrust settings must be used on each engine tested. A dataset consists of nvPMMC measurements made at each thrust setting across the thrust range chosen by the applicant for each engine. Plot all nvPMMC measurements versus thrust setting. ( i ) Method 1— ( A ) Average the individual data points measured at each thrust setting to develop one dataset of nvPM mass concentration for each engine tested, creating an average dataset for each engine; and
( B ) Use the averages generated in paragraph (c)(1) of this section to develop a single curve fit to determine the overall maximum nvPMMC value;
( ii ) Method 2— ( A ) Measure individual data points of nvPMMC versus thrust. Using all datasets generated for each engine physically tested, develop a single, separate curve fit;
( B ) Determine the maximum nvPMMC from each engine curve fit resulting from paragraph (c)(1) of this section; and
( C ) If more than one engine is physically tested, average the nvPMMC values from paragraph (c)(2) of this section to determine the overall maximum nvPMMC value for the model tested; or
( iii ) Method 3— ( A ) Develop a curve fit of nvPMMC versus thrust for each test conducted on each engine physically tested;
( B ) From each curve fit developed in paragraph (c)(1) of this section, use the resultant curve fit equation to solve for each maximum;
( C ) Average the maximum values for each engine physically tested; and
( D ) Average the maximum values determined in paragraph (c)(1)(iii)(C) of this section to determine the overall average maximum nvPMMC value.
( 2 ) Using the data measured in § 34.71(b) of this part, determine the nvPM characteristic levels for nvPMnum and nvPMmass as follows: ( i ) Average all nvPMnum and nvPMmass measurements in units of number of particles per kN or mg per kN, as applicable, from each emissions test at each percentage of rated output thrust setting;
( ii ) Multiply the averaged measurement from paragraph (a)(2)(i) of this section by the appropriate time in mode (TIM) as shown in § 34.71(h);
( iii ) Sum the products from paragraph (a)(2)(ii) of this section to determine the LTO values for nvPMnum and nvPMmass; and
( iv ) Divide the result of paragraph (a)(2)(iii) of this section by the characteristic level factor, shown in Table A6-1 of Appendix 6 of ICAO Annex 16, Volume II (incorporated by reference, see § 34.4), for the number of engines physically tested to determine the nvPMmass and nvPMnum characteristic values.
( d ) The data used to determine the regressed curves must meet a 90% confidence interval, CI90, limit of ±1.5% of each nvPM limit specified in § 34.25 of this part. If a certification test fails to meet the CI90 limit, the engine type may still comply with the requirements. Failure may be caused by excessive data scatter, too few data points, or erroneous data used to regress an accurate curve. Without deleting or removing any prior measurement data, additional data acquired from further tests may improve the CI90 by adding to the sample population.
( e ) The following information must be reported to the FAA substantiating compliance with nvPM limits of § 34.25 of this part: ( 1 ) The values of nvPM emissions measured and computed in accordance with the procedures and calculated as required by this subpart in § 34.71 of this part and paragraphs (a) through (d) of this section;
( 2 ) For each engine tested: ( i ) Engine model, series, and serial number;
( ii ) Rated thrust (kN);
( iii ) Overall pressure ratio;
( iv ) The methods of data acquisition; and
( v ) The method of data analysis chosen by the applicant under paragraphs (a) through (d) of this section.
( 3 ) Demonstration that the fuel used for each test is in compliance with the fuel specification listed in Appendix 4 of ICAO Annex 16, Volume II (incorporated by reference, see § 34.4). For the fuel used for nvPM emissions certification, include the following fuel characteristics: ( i ) Hydrogen/carbon ratio;
( ii ) Net heat of combustion (MJ/kg);
( iii ) Hydrogen content (mass per cent);
( iv ) Total aromatics content (volume per cent);
( v ) Naphthalene content (volume per cent); and
( vi ) Sulfur content (ppm by mass).
( 4 ) For each engine tested for certification purposes, the following values measured and computed in accordance with the procedures of § 34.71 of this part: ( i ) Fuel flow (kg/s) at each thrust setting of the LTO cycle;
( ii ) nvPM EImass (mg/kg of fuel) at each thrust setting of the LTO cycle;
( iii ) nvPM mass emission rate [nvPM EImass × fuel flow] in mg/s;
( iv ) nvPM EInum (particles/kg of fuel) at each thrust setting of the LTO cycle;
( v ) nvPM number emission rate [nvPM EInum × fuel flow] in particles/s;
( vi ) Total gross emissions of nvPM mass measured over the LTO cycle in mg;
( vii ) Total gross emissions of nvPM number measured over the LTO cycle in particles;
( viii ) LTO nvPMmass/thrust in mg/kN;
( ix ) LTO nvPMnum/thrust in particles/kN; and
( x ) Maximum nvPMMC in μg/m3; and
( 5 ) For each engine tested for certification purposes, the characteristic levels for the maximum nvPMMC, the LTO nvPMmass/thrust, and the LTO nvPMnum/thrust.