A safety consideration of IMA based on SISPHA

Integrated Modular Avionics (IMA), which is universally considered as safety-critical and software-intensive system, can effectively improve the efficiency comparing with the traditional avionics. However, it also brings up a series of problems, such as fault propagation and functional margin blur. Based on the ideology of preliminary hazard analysis(PHA), this paper firstly makes a rethinking about the common PHA, including the inner-philosophy, misinterpretations and limits, then a safety analysis method-Software-Intensive System PHA(SISPHA)-is presented through combining a consideration of Software-Intensive System characteristics and some PHA application experiences in the software safety area. Finally, on the basis of a certain unmanned aerial vehicle(UAV) IMA design scheme, an application case is provided, which can help explore the safety-critical problems and support the further safety analysis and design.