Gas turbines are high value, capital equipment around which plant or vehicle uptime is highly dependent. These turbines continually run at their optimum rotational speed, so relatively small performance changes can result in significant cost or even failure. General wear and tear and combustion damage eventually degrades the engine performance and an overhaul is deemed necessary. The engine is de-commissioned and installed in a secure test stand for testing and measurement. Testing is expensive, so ensuring good quality, valid data – every time – is essential.