(a) Overview. Measure emissions using the equipment, procedures, and test fuel specified in Appendices 1 through 8 of ICAO Annex 16 (incorporated by reference, see § 1031.210) as described in this section (referenced in this section as “ICAO Appendix #”). For turboprop engines, use the procedures specified in ICAO Annex 16 for turbofan engines, consistent with good engineering judgment.

(b) Test fuel specifications. Use a test fuel meeting the specifications described in ICAO Appendix 4. The test fuel must not have additives whose purpose is to suppress smoke, such as organometallic compounds.

(c) Test conditions. Prepare test engines by including accessories that are available with production engines if they can reasonably be expected to influence emissions.

(1) The test engine may not extract shaft power or bleed service air to provide power to auxiliary gearbox-mounted components required to drive aircraft systems.

(2) Test engines must reach a steady operating temperature before the start of emission measurements.

(d) Alternate procedures. In consultation with the EPA, the FAA may approve alternate procedures for measuring emissions. This might include testing and sampling methods, analytical techniques, and equipment specifications that differ from those specified in this part. An applicant for type certification may request this approval by sending a written request with supporting justification to the FAA and to the Designated EPA Program Officer. Such a request may be approved only in the following circumstances:

(1) The engine cannot be tested using the specified procedures.

(2) The alternate procedure is shown to be equivalent to or better (e.g., more accurate or precise) than the specified procedure.

(e) LTO cycles. The following landing and take-off (LTO) cycles apply for emission testing and calculating weighted LTO values:

(f) Pollutant-specific test provisions. Use the following provisions to demonstrate whether engines meet the applicable standards:

(1) Smoke number. Use the equipment and procedures specified in ICAO Appendix 2 and ICAO Appendix 6. Test the engine at sufficient thrust settings to determine and compute the maximum smoke number across the engine operating thrust range.

(2) nvPM. Use the equipment and procedures specified in ICAO Appendix 7 and ICAO Appendix 6, as applicable:

(i) Maximum nvPM mass concentration. Test the engine at sufficient thrust settings to determine and compute the maximum nvPM mass concentration produced by the engine across the engine operating thrust range, according to the procedures of ICAO Appendix 7.

(ii) LTO nvPM mass and number. Test the engine at sufficient thrust settings to determine the engine's nvPM mass and nvPM number at the percent of rated output identified in table 1 to paragraph (e) of this section.

(3) HC, CO, and NOX. Use the equipment and procedures specified in ICAO Appendix 3, ICAO Appendix 5, and ICAO Appendix 6, as applicable. Test the engine at sufficient thrust settings to determine the engine's HC, CO, and NOX emissions at the percent of rated output identified in table 1 to paragraph (e) of this section.

(4) CO2. Calculate CO2 emission values from fuel mass flow rate measurements in ICAO Appendix 3 and ICAO Appendix 5 or, alternatively, according to the CO2 measurement criteria in ICAO Appendix 3 and ICAO Appendix 5.

(g) Characteristic level. The compliance demonstration consists of establishing a mean value from testing some number of engines, then calculating a “characteristic level” by applying a set of statistical factors in ICAO Appendix 6 that take into account the number of engines tested. Round each characteristic level to the same number of decimal places as the corresponding standard. 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.

(h) System loss corrected nvPM emission indices. Use the equipment and procedures specified in ICAO Appendix 8, as applicable, to determine system loss corrected nvPM emission indices.