Light carbon structures are increasingly used in modern aircrafts for reducing weight and thus fuel consumption. The carbon materials are more sensitive to overheating than metals. Hot air ducts are used to conduct air heated by engine exhaust to the cabin heating system. At several locations, those hot air ducts are installed within or in close proximity to the carbon structures. Therefore, reliable and precise hot air leak detection is an essential safety feature of modern aircrafts. The proposed activity aims at developing an innovative, powerful and reliable fibre-optic technology for an aircraft hot air leak detection system and validating it in a representative aircraft environment.

State-of-the-art electrical hot air leak detection systems detect and localize leaks in aircraft hot air ducts by analysing electric shortcuts. However, the response of such systems just indicates that the critical temperature is exceeded. It is impossible to vary the threshold setting along the cable and false alarms due to stray signals are common. Localization of leaks is difficult, and the sensor cables are irreversibly damaged by exceeding the critical temperature.