The knowledge of the application environment is one of the main dimensioning factors for reliability and maintenance. Indeed, to avoid over-specifications and the associated costs, it is necessary to know the mission profile that a system will be submitted to. Indeed, aircrafts are submitted to various stresses during their flights: lightning, important variations of temperatures, mechanical stresses… As an example, a commercial aircraft is blasted by lightning twice a year in average. It is also submitted to huge variations of temperature, from -55°C to 125°C. Simultaneously, mechanical stresses occur on the aircraft, especially during take off and landing. Shocks could impact different locations of the aircraft as well. The hydraulic and electrical systems and the aircraft structures should resist to these stresses to assure the safety of the aircraft and the passengers onboard. The failure rate of a specific function in an aircraft is estimated in average at 10~(-9) per hour. In order to better know the environment where an aircraft is flying, EADS IW have developed several smart and embedded systems able to record different parameters such as cracks, lightning, temperature or vibration data. Once the exact environment is known, the specifications and the reliability of a system can be established accordingly. To improve the maintenances, other monitoring systems named HUMS (Health and Usage Monitoring System) can be described as smart systems. They generally perform the same kind of monitoring but integrate some more intelligent functions. To use them, the environment has to be known and some analyses are performed to give the health of the device under test in real-time and its localisation, without additional off board processing.
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