Aircraft propulsion affects the performance and stability of an aircraft. It influences the aircraft’s safety as well as the economics of its operation. After all, differences of as little as 0.5% in fuel consumption can have substantial effects on the operational cost of an aircraft. Precise measurements of the effects of the integrated propulsion are therefore of crucial importance in the development phase of an aircraft. 

The following issues are among those of particular relevance in propulsion-related measurements: 

The thrust/drag performance, which must be favorable to ensure sufficient cruise economy, as well as an optimum lift to drag ratio during take-off in order to realize adequate payload capability
The influence of the fan exhaust flow or propeller slipstream, on performance and stability in cruise and high lift configuration of the aircraft
The influence of the engine installation on the aerodynamic performance of the wing
The effect of the thrust reverser mode on the engine cut off speed and the aircraft’s performance, stability and structural integrity