Aerospace electrical systems are continuing to increase their voltage levels to meet the on-board power demands of more-electric aircraft (MEA) where
hydraulic and pneumatic systems are replaced with electrical equivalents. This trend will only continue as hybrid and allelectric aircraft are developed. These higher power demands require the use of higher voltages and as such it is essential to explore the behaviour of the insulation system in the aerospace
environment. This insulation must operate in an environment where the operating temperatures range from 250°C to -65°C, the air pressure is around one tenth of that at ground level and where the levels of humidity and ozone vary rapidly. Understanding the impact of these variables on aircraft high
voltage insulation systems is crucial in predicting their behaviour and lifetime. Our work with the IAGOS atmospheric dataset presents worst-case and typical flight environments for higher than expected cruising altitudes, and uses the
findings to compare the relative rates of degradation of insulating materials at ground and cruising altitudes.