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Remote Sensing Technique for Aero-engine Emission Certification and Monitoring


It has been demonstrated in the last five years, via AEROJET and AEROJET II, that non-intrusive techniques like Fourier Transform Infrared spectroscopy (FTIR) and Laser Induced Incandescence (LII) are relevant to the measurement of aero-engine exhaust gases. These methods have been compared with intrusive methods within AEROJET II.

This success has opened the path for their standardisation. Simultaneously, the aircraft engine industry stresses the need for a measurement method compatible with cost effectiveness, short-term implementation, fast availability of results and accuracy, meeting ICAO emission certification needs.

Project objectives

The aim of AEROTEST is to achieve a high level of confidence in aircraft engine emission measurements with a view to using the remote optical technique for engine emissions certification. Two major objectives will allow meeting the engine manufacturers’ needs:

  • the first and major objective is to address the standardisation issues, the ultimate aim being to promote non-intrusive techniques to ICAO for engine emission certification, following a complete quality assurance (QA) and quality control (QC) approach, and developing procedures for calibration, set up and operation.
  • the second objective is to develop validated techniques for gas turbine monitoring, using emissions data, which is to be used routinely by engine manufacturers, both in development test programmes and for engine health monitoring (EHM).
Non-intrusive equipment in a test rig
Non-intrusive equipment in a test rig

Description of the work

Six Work Packages have been defined to reach the AEROTEST objectives:

  • Work Package 1 addresses all the quality aspects to be taken into account and defines the QA/QC approach to be followed to achieve the level of confidence and reliability needed for certification. It also addresses standards matters and correlation with previous intrusive data. This Work Package is essential in the sense that it defines the parameters that will insure the quality of the data, both from instrumentation and operation viewpoints.
  • Work Package 2 is dedicated to the measurement methods calibration, namely the LII and the FTIR techniques. The calibration and measurement validation tests will be done both in laboratory and test bed environments.
  • Work Package 3 is about the integration of the LII and the FTIR components into a unified system controlling both the LII and FTIR, and acquisition and processing. Input or control parameters will be minimised and the data processing will be automated. Non-expert operators will also be able to obtain measurements with this system.
  • Work Package 4 is focused on emerging technologies. The consortium needs to be aware of such technologies that could bring simplification to the system. It is organised in thematic areas and will insure that the knowledge is distributed across the consortium. Despite its small size, Work Package 4 was felt to be important enough to be independent.
  • Work Package 5 highlights the fact that the technique can serve not only as a certification tool but also for other purposes, such as the application to gas turbine health monitoring. A model of engine emissions affected by component failure will be developed and correlated to engine emissions measurements.
  • Work Package 6 is focused on the dissemination of the results and the outcome of the project. Awareness feedback from standards and regulation authorities is very important to the project, and will be achieved in this Work Package.

Expected results

The expected achievement is the acceptance of non-intrusive methods for gas turbine monitoring. A proposition of recommended practices to ICAO will be established at the end of the project, taking into account feedback from certification authorities acquired during discussions and presentations.

Although AEROTEST is limited to gas turbines, the same techniques can be applied to other types of exhausts, leading to a wide range of possibilities in health and continuous emissions monitoring.

AEROTEST equipment implementation
AEROTEST equipment implementation