25-08-2017, 09:32 PM
GUIDELINES ON THE USE OF PROCEDURES IN THE EMISSIONS CERTIFICATION OF AIRCRAFT ENGINES
GuidelinesProceduresEmissionsCertificationAircraftEngine.pdf (Size: 105.2 KB / Downloads: 44)
EMISSIONS COMPLIANCE DEMONSTRATION PLAN
Prior to undertaking an emissions certification demonstration, the applicant is
normally required to submit to the certificating authority an emissions compliance
demonstration plan. This plan contains the method by which the applicant proposes to show
compliance with the emissions requirements. Approval of this plan and the proposed use of
any equivalent procedure remains with the certificating authority. The determination of
equivalency for any procedure or group of procedures must be based upon the consideration
of all pertinent facts relating to the application.
1.3.2 Emissions compliance demonstration plans should include the following
types of information:
a) introduction
· description of the engine emissions certification basis, i.e. the
applicable Annex 16, Volume II amendment and chapter;
b) engine description
· type, model number and specific details of the basic configuration to
be certified;
c) engine emissions certification methodology
· test concepts, equivalent procedures and technical procedures;
d) test description
· test methods to comply with the emissions Standards;
e) measurement system
· description of measurement and sampling system components and
procedures, including calibration procedures, that are intended to be
used to demonstrate compliance with the emissions Standards; and
f) data evaluation procedures
· emissions evaluation and adjustment procedures (including
equivalent and technical procedures such as those provided in these
guidelines) to be used in compliance with the provisions of Annex
16, Volume II appropriate to the engine type being certificated.
EMISSIONS CERTIFICATION REPORTS
Following completion of an emissions certification demonstration test, an
applicant is normally required to submit an emissions certification report. This report provides
a complete description of the test process and the test results with respect to compliance with
the provisions of Annex 16, Volume II.
These reports should include the following types of information:
a) basis for test approval
· the approved emissions certification compliance plan for the engine
type and model being certificated;
b) description of tests
· actual configurations tested and non-conforming items (with
justification that they are not significant to emissions, or if
significant, can be dealt with by an approved method), test
methodology (including equivalent procedures and technical
procedures), tests conducted, test data validity, and data analysis and
adjustment procedures used;
c) test results
· data to demonstrate compliance with the provisions of Annex 16,
Volume II regarding maximum emissions levels for the engine type
being certificated; and
d) references.
Turbo-jet and turbofan engines intended for propulsion only at subsonic
speeds
General
Applicability
The provisions of this chapter shall also apply to engines designed for applications that
otherwise would have been fulfilled by turbo-jet and turbofan engines.
Explanatory Information
This sentence anticipates the introduction of future engine technologies. The emissions
Standards in Chapter 2 would also be applicable to future engine types not categorized as a
turbo-jet or turbofan but intended for use in international air transport services. The provision
above is not applicable to turbo-prop engines.
Emissions involved [Reserved]
Units of measurement
Explanatory Information
Smoke level is determined indirectly, by means of the loss of reflectance of a filter used to
trap smoke particles from a prescribed mass of exhaust per unit area of filter. The result is a
dimensionless smoke number “SN” which acts as a surrogate for, or indicator of, plume
opacity. These smoke sampling and measurement procedures standardized in Annex 16,
Appendix 2 are derived from SAE Aerospace Recommended Practice (ARP) 1179, Aircraft
Gas Turbine Exhaust Smoke Measurement.
The smoke measurement standard was developed for engines that generated smoke at
considerably higher levels than are seen today. This affects the relative accuracy of the
method. The measurement is considered (by the SAE E-31 Committee that developed the
method) to be no more accurate than ±3 SN. At smoke levels of SN 50-60 this represents an
accuracy of 6 to 5 per cent. At regulatory standards of 30 and below, relative accuracy
becomes 10 to 20 per cent or more.
2.1.4 Reference conditions
2.1.4.1 Atmospheric conditions