Measurement Quality Assessment of an On-Wing Engine Thrust Measurement System

Aircraft engine maintenance is performed on an on-condition basis. Monitoring the engine condition during operation is important to provide an efficient maintenance. Engine Condition Monitoring has thus become a standard procedure during operation. However, one of the most important parameters, the engine thrust, is not directly measured and can therefore not be monitored, which makes it difficult to distinguish whether deteriorating trends e.g. in fuel comsumption must be attributed to the engine (e.g. due to thermodynamic wear) or to the aircraft (e.g. due to increased drag). Being able to make this distinction would improve troubleshooting and maintenance planning and thus help to reduce the cost of ownership of an aircraft. This paper describes the development and quality assessment of a system for direct engine thrust measurement during the normal engine operation. The system was designed, calibrated and validated with engine test runs. After the necessary certification of the whole system a flight test campaign to validate the system, when installed on an aircraft, was started. In the presented work an assessment of the quality of measured data from the first period of the ongoing flight test is presented.