OMTDR-based embedded cable diagnosis for mutliple fire zones detection and location in aircraft engines

Nowadays, the safety of passengers on board is the first preoccupation for aircraft manufacturers. For this reason, next-generation helicopters are now being designed with a wide range of advanced technologies to reinforce safety. In this context, a new fire detection system based on reflectometry is proposed for monitoring the engines of helicopters. The main idea is to mesh engines by a fireproof cable that serves not only as a physical support of test signals, but also as a fire detection sensor. To do so, OMTDR technology is integrated into an electronic device analyzing in permanence the impedance variation of the sensor caused by a temperature increase. The proposed fire detection system permits not only to detect the fire as conventional systems, but also to locate it with accuracy. Moreover, the fire detection sensor becomes intelligent since it is able to self-diagnosis (i.e. hard fault, aging, etc.) thanks to OMTDR use. For feasibility proof, a demonstrator is developed and tested in laboratory. Experimental results show that the fire detection system is able to detect and locate multiple fire zones simultaneously without loss of accuracy.