and pressures, laser and optic checks, zero count test, lower detection and concentration linearity tests.
Evaluating the instrument in this manner is useful for understanding instrument drift.
15.27. Appendix 7, 10: Additional system checks prior to an engine test If new system components are being utilized, it may be beneficial to perform additional system checks prior to an engine test to ensure the nvPM sampling and measurement system operates correctly during an engine test. An example of a new system component is a different type of probe.
To check that summation of the flows in Module 5 match that of Module 3 flowrate, an optional flow measurement check may be performed by disconnecting Module 3 from Module 2 and placing a flow meter at Module 3 inlet to verify that the flow is within 25 slpm ± 2 slpm, while ensuring flow rates in each Splitter 2 flow path are equal to those to be used during engine test.
To help ensure Diluter 1 operability at low power engine conditions, when probe inlet pressure is low, an optional operational check may be performed prior to the engine test using the following recommended procedure:
a) CO2 calibration gas containing between 3 per cent to 5 per cent CO2 should be connected to the sampling probe without over-pressurising the probe tip inlet, such that the calibration gas enters Section 1 near ambient pressure.
b) The nvPM sampling and measurement system should be operated at the flow rates and temperatures used during engine testing.
c) P1 pressure control valve and the optional shut-off valve on the excess sample flow path should be closed.
d) DF1 should be calculated. If DF1 is found to be above 14, then the GL flow rate should be reduced.
Blockage of Diluter 1 orifice nozzle may cause DF1 to increase above 14 indicating that the orifice needs to be cleaned. The flow schematic for the optional Diluter 1 operability check is shown in Figure 2- 17.
Figure 2-17. Flow schematic for Diluter 1 operability check Page 48 of 57
15.28. Appendix 7, 10.5.1.1: Ambient nvPM measurement Ambient nvPM mass and number concentrations are measured to monitor for elevated nv PM levels entrained into the engine inlet air that could contaminate low measurements of engine exhaust nvPM emissions.
Inside an enclosed testbed, during engine preparation and prior to an engine start, there may be sources of nvPM that can cause ambient nvPM levels to be slightly elevated. For example, use of near -vicinity vehicles or cherrypickers. To reduce ambient nvPM to representative levels, the testbed air needs to be flushed through with outside ambient air. One possible flushing method is to utilise test cell fans, if installed. Another possible method is to use entrained air from a running engine. Depending on the size of the test cell and air flow, it could take a few minutes to flush through thoroughly. Thus for testbed flushing methods a minimum of 5 minutes operation is recommended prior to obtaining an ambient nvPM measurement.
15.29. Appendix 7, 10.6: VPR dilution factor calibration check using real time measurements of CO2 An alternative to performing the operational VPR dilution checks of the DF2 values from a competent laboratory is using real time measurements of CO2 at the CPC inlet downstream of the second stage dilution, [CO2]dil2, as shown in Figure 2-18.
Filtered diluent gas (air or N )2
0.1 ppm CO< 2 VPR (DF )2 CO analyser2 100 ppm) (typically < Figure 2-18. Alternative set-up to determine DF2 CO2 measurement capability for concentration levels as low as 5 ppm is needed for this procedure. The suitable range for the CO2 analyser is typically 30 to 70 ppm full scale. Ideally, the measured sample gas concentrations should be in the 20 to 95 per cent full scale range. If this alternative check is performed, the VPR diluent gas should contain less than 0.1 ppm of CO2. The sample does not need to be dried.
During an engine test, DF2 as calculated below should be used to check if the VPR meets the calibration DF2 values provided by the competent laboratory.
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In addition, using this option eliminates the need for dilution factor operational checks pre and post engine test series.
16. A ttachments to ICAO A 16V2
16.1. Symbols
16.2. Attachment A, 1: Symbols L is the interference effect of CO2 on the measurement of CO interpreted in terms of a zero shift.
L’ is the interference effect of CO2 on the measurement of NO and NOx interpreted in terms of a sensitivity change.
Note.— The values of these interference effects are specific to, and must be determined for, the individual analysers.
16.3. Attachment A, 1: Symbols M is the interference effect of H2O on the measurement of CO interpreted in terms of a zero shift.
M’ is the interference effect of H2O on the measurement of NO and NOx interpreted in terms of a sensitivity change.
Note.— The values of these interference effects are specific to, and must be determined for, the individual analysers.
17. B asis of calculation of EI and AFR parameter s
17.1. Attachment A, 2.1: Basis of Calculation of EI and AFR Parameters (AFR formulation) This is a slightly different formulation for AFR than that stated in Annex 16, Volume II, Appendix 3, 7.1.2, “Basic parameters”. In this formulation m, the “number of C atoms in characteristic fuel molecule” is placed within the bracket. There is no particular advantage to using one formulation over the other.
17.2. Attachment A, 2.5: Basis of Calculation of EI and AFR Parameters (interference effects) With a zero-shift interference effect, the interfering species creates an offset on the measurement, which does not vary with the concentration measured. This is the case for the interference of CO 2 and H2O on CO.
With a sensitivity change interference effect, the interfering species modifies the slope of the response of the analyser; therefore, the effect is proportional to the concentration measured. This is the case for the interference of CO2 and H2O on NO.
Note.— The values of these interference effects are specific to, and must be determined for, the individual analysers.
18. Al ternative Methodology — Numerical Solution
18.1. Attachment A, 4: Alternative Methodology – Numerical Solution Details explaining various calculation procedures can be found in SAE Aerospace Recommended Practice (ARP) 1533C — Procedure for the Analysis and Evaluation of Gaseous Emissions from Aircraft Page 50 of 57
Engines. ARP1533C includes, among other things, derivation of equations, the combustion chemical equation and a matrix method of solving the combustion chemical equation.
19. Additional Guidance
19.1. Engine Emissions Data Assurance Program (EDAP) The Engine Emissions Data Assurance Program (EDAP) consists of three products designed to provide guidance, validation and quality assurance for the acquisition and reporting of engine emissions data that is generated by manufacturers during engine certification. EDAP users may include the FAA’s Office of Environment and Energy (AEE-300), FAA ACOs and ECO, ODA Unit Members, Designated Engineering Representatives (DERs) and others that are interested in the acquisition and reporting of engine emissions data.
The Engine EDAP products include 1) a spreadsheet tool that uses smoke and emissions test data to automatically calculate emissions indices in a format needed to show compliance with applicable emissions regulations, 2) a User Guide for the EDAP Spreadsheet Tool which defines the functionality of the tool, underlying calculations, and reportable emissions data, and 3) checklists that specify various gaseous emissions and smoke number sampling requirements pursuant to A16V2 and requirements for data reporting.
The Engine EDAP Spreadsheet Tool is similar to other programs that manufactures may use to manage engine test data, calculate characteristic emissions and determine compliance with part 34. EDAP enables users to assess the quality of emissions certification data that is being acquired and processed and, in turn, generated and reported for compliance purposes.
The Engine EDAP spreadsheet tool, User Guide and checklists may be obtained from AEE -300 by contacting the AEE-300 Emissions Division Manager with Office of Environment and Energy at 202-267- 3576 or 202-267-3577.
19.2. Additional Information For additional information on this AC or other aviation environmental topics, please contact the AEE-300 Emissions Division Manager with the Office of Environment and Energy at 202-267-3576 or 202-267- 3577.
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20. Attachment 1: 14 CFR 34.1 Definitions As used in this Advisory Circular, all terms not defined herein shall have the meaning given them in the Clean Air Act, as amended (42 U.S.C. 7401 et. seq.):appendices Act means the Clean Air Act, as amended (42 U.S.C. 7401 et. seq.)
Administrator means the Administrator of the Federal Aviation Administration or any person to whom he has delegated his authority in the matter concerned.
Administrator of the EPA means the Administrator of the Environmental Protection Agency and any other officer or employee of the Environmental Protection Agency to whom the authority involved may be delegated.
Aircraft as used in this part means any airplane as defined in 14 CFR part 1.1 for which a U.S. standard airworthiness certificate or equivalent foreign airworthiness certificate is issued.
Aircraft engine means a propulsion engine which is installed in, or which is manufactured for installation in, an aircraft.
Aircraft gas turbine engine means a turboprop, turbofan, or turbojet aircraft engine.
Characteristic level has the meaning given in Appendix 6 of ICAO Annex 16 as of July 2008. The characteristic level is a calculated emission level for each pollutant based on a statistical assessment of measured emissions from multiple tests.
Class TP means all aircraft turboprop engines.
Class TF means all turbofan or turbojet aircraft engines or aircraft engines designed for applications that otherwise would have been fulfilled by turbojet and turbofan engines except engines of class T3, T8, and TSS.
Class T3 means all aircraft gas turbine engines of the JT3D model family.
Class T8 means all aircraft gas turbine engines of the JT8D model family.
Class TSS means all aircraft gas turbine engines employed for propulsion of aircraft designed to operate at supersonic flight speeds.
Commercial aircraft engine means any aircraft engine used or intended for use by an “air carrier” (including those engaged in “intrastate air transportation”) or a “commercial operator” (including those engaged in “intrastate air transportation”) as these terms are defined in Title 49 of the United States Code and Title 14 of the Code of Federal Regulations.
Commercial aircraft gas turbine engine means a turboprop, turbofan, or turbojet commercial aircraft engine..
Date of manufacture of an engine is the date the inspection acceptance records reflect that the engine is complete and meets the FAA approved type design.
Derivative engine for emissions certification purposes means an engine that is similar in design to an engine that has demonstrated compliance with the applicable exhaust emission standards of this part, as determined by the FAA, and has a U.S. type certificate issued in accordance with part 33 of this chapter.
Emission measurement system means all of the equipment necessary to transport the emission sample and measure the level of emissions. This includes the sample system and the instrumentation system.
Engine model means all commercial aircraft turbine engines which are of the same general series, displacement, and design characteristics and are approved under the same type certificate.
Excepted, as used in 14 CFR § 34.9, means an engine that may be produced and sold that does not meet otherwise applicable standards. [See “except,” above.] Excepted engines must conform to regulatory conditions specified for an exception in § 34.9. Excepted engines are subject to the standards of this part even though they are not required to comply with the otherwise applicable Page 52 of 57
requirements. Engines excepted with respect to certain standards must comply with other standards from which they are not specifically excepted.
Exempt means an engine that does not meet certain applicable standards but may be produced and sold under the terms allowed by a grant of exemption issued pursuant to § 34.7 of this part and part 11 of this chapter. Exempted engines must conform to regulatory conditions specified in the exemption as well as other applicable regulations. Exempted engines are subject to the standards of this part even though they are not required to comply with the otherwise applicable requirements. Engines exempted with respect to certain standards must comply with other standards as a condition of the exemption.
Exhaust emissions means substances emitted into the atmosphere from the exhaust discharge nozzle of an aircraft or aircraft engine.
In-use aircraft gas turbine engine means an aircraft gas turbine engine which is in service.
Introduction date means the date of manufacture of the first individual production engine of a given engine model or engine type certificate family to be certificated. Neither test engines nor engines not placed into service affect this date.
New aircraft turbine engine means an aircraft gas turbine engine which has never been in service.
Non-volatile particulate matter (nvPM) means emitted particles that remain at the exhaust nozzle exit plane of a gas turbine engine, and that did not volatilize after being heated to a temperature of at least 350º C.
Power setting means the power or thrust output of an engine in terms of kilonewtons thrust for turbojet and turbofan engines or shaft power in terms of kilowatts for turboprop engines.
Rated output (rO) means the maximum power/thrust available for takeoff at standard day conditions as approved for the engine by the Federal Aviation Administration, including reheat contribution where applicable, but excluding any contribution due to water injection, expressed in kilowatts or kilonewtons (as applicable), rounded to at least three significant figures.
Rated pressure ratio (rPR) means the ratio between the combustor inlet pressure and the engine inlet pressure achieved by an engine operation at rated output, rounded to at least three significant figures.
Reference day conditions means the reference ambient conditions to which the gaseous emissions (HC and smoke) are to be corrected. The reference day conditions are as follows: Temperature = 15 °C, specific humidity = 0.00634 kg H2O/kg of dry air, and pressure = 101325 Pa.
Sample system means the system which provides for the transportation of the gaseous emission sample from the sample probe to the inlet of the instrumentation system.
Shaft power means only the measured shaft power output of a turboprop engine.
Smoke means the matter in exhaust emissions which obscures the transmission of light..
Smoke number (SN) means the dimensionless term quantifying smoke emissions.
Standard day conditions means the following ambient conditions: temperature = 15 °C, specific humidity = 0.00634 kg H2O/kg dry air, and pressure = 101.325 kPa. 14 CFR 34.1.
Taxi/idle (in) means those aircraft operations involving taxi and idle between the time of landing roll -out and final shutdown of all propulsion engines.
Taxi/idle (out) means those aircraft operations involving taxi and idle between the time of initial starting of the propulsion engine(s) used for the taxi and the turn onto the duty runway. 14 CFR 34.1.
Tier, as used in [Part 14], is a designation related to the NOX emission standard for the engine as specified in § 34.21 or § 34.23 of this part (e.g., Tier 0).
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21. Attachment 2: 14 CFR 34.2 Abbreviations The abbreviations used in this part have the following meanings in both upper and lower case:
CO2 Carbon dioxide CO Carbon monoxide EI Emissions index EPA United States Environmental Protection Agency FAA Federal Aviation Administration, United States Department of Transportation g Gram(s) HC Hydrocarbon(s) HP Horsepower hr Hour(s) H2O water kg Kilogram(s) kJ Kilojoule(s) kN Kilonewton(s) kW Kilowatt(s) lb Pound(s) lbf Pound force LTO Landing and takeoff m Meter mg Milligram µg Microgram min Minute(s) NOX Oxides of nitrogen nvPM Non-volatile particulate matter nvPMmass (ICAO EImass) Non-volatile particulate matter mass nvPMnum (ICAO EInum) Non-volatile particulate matter number nvPMMC (ICAO nvPMmass) Non-volatile particulate matter massmass concentration Pa Pascal(s) rO Rated output rPR Rated pressure ratio sec Second(s) SN Smoke number Page 54 of 57
SP Shaft power T Temperature, degrees Kelvin TIM Time in mode ° Degree °C Degrees Celsius % Percent [Doc. No. 25613, 55 FR 32861, Aug. 10, 1990, as amended by Amdt. 34-3, 64 FR 5559, Feb. 3, 1999; Amdt. 34-5, 77 FR 76850, Dec. 31, 2012] Page 55 of 57
Numb er of engin es tested
(i) CO HC NOx SN nvPM mass conce ntratio n
nvPM LTO mass
nvPM LTO number
1 0.814 7
0.649 3
0.862 7
0.776 9
0.776 9 0.719 4 0.719 4 2 0.877 7
0.768 5
0.909 4
0.852 7
0.852 7 0.814 8 0.814 8 3 0.924 6
0.857 2
0.944 1
0.909 1
0.909 1 0.885 8 0.885 8 4 0.934 7
0.876 4
0.951 6
0.921 3
0.921 3 0.901 1 0.901 1 5 0.941 6
0.889 4
0.956 7
0.929 6
0.929 6 0.911 6 0.911 6 6 0.946 7
0.899 0
0.960 5
0.935 8
0.935 8 0.919 3 0.919 3 7 0.950 6
0.906 5
0.963 4
0.940 5
0.940 5 0.925 2 0.925 2 8 0.953 8
0.912 6
0.965 8
0.944 4
0.944 4 0.930 1 0.930 1 9 0.956 5
0.917 6
0.967 7
0.947 6
0.947 6 0.934 1 0.934 1 10 0.958 7
0.921 8
0.969 4
0.950 2
0.950 2 0.937 5
0.937 5 more than 10 1-
0.130 59 1-
0.247 - 24 1-
0.096 78 1-
0.157
36 1-
0.157 36 1 − 0.197 78 1 − 0.197 78
√𝐴𝐴 √𝐴𝐴 √𝐴𝐴 √𝐴𝐴 √𝐴𝐴 √𝐴𝐴 √𝐴𝐴 Page 56 of 57
22. Attachment 3: ICAO Annex 16, Volume II, Amendment 9, July, 2017, Appendix 6, Table A6-1 Table A6-1. Coefficients to determine characteristic levels