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New ICAO publication (Doc 9501-2)

Doc 9501, Environmental Technical Manual Volume II, Procedures for the Emissions Certification of Aircraft Engines. Fifth Edition, 2023.

The revision of the ICAO Environmental Technical Manual (Doc 9501), Volume II – Procedures for the Emissions Certification of Aircraft Engines, Fourth Edition, includes material that has been approved by the ICAO Committee on Aviation Environmental Protection (CAEP) during its twelfth meeting (CAEP/12) in February 2022. This manual is to be periodically revised under the supervision of the CAEP Steering Group and is intended to make the most recent information available to certificating authorities, aircraft engine emissions certification applicants and other interested parties in a timely manner, aiming at achieving the highest degree of harmonization possible. The technical procedures and equivalent procedures described in this edition are consistent with currently accepted techniques and modern instrumentation. In this respect, this edition is compatible with Amendment 10 of Annex 16, Volume II. This edition and subsequent revisions that may be approved by the CAEP Steering Group will be posted on the ICAO website ( under “publications” until the latest approved revision is submitted to CAEP for formal endorsement and subsequent publication by ICAO.


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