A Case Study in Safety, Security, and Availability of Wireless-Enabled Aircraft Communication Networks

What is it about?

As the costs of fuel and maintenance increase and regulations on weight and environmental impact tighten, there is an increasing push to transition on-board aircraft networks to wireless, reducing weight, fuel, maintenance time, and pollution. We outline a candidate short-range hybrid wired/wireless network for aircraft on-board communications using the common ZigBee protocol and privacy-preserving search implemented as a secure publish/subscribe system using specially coded meta-data. Formally specifying safety and security properties and modeling the network in \textsc{nuXmv} enables verification and fault analysis via model checking and lays the groundwork for future certification avenues. We report on our experiments building and testing our candidate hybrid network and report on overhead and availability for encrypted and fault-tolerant communications, and propose a system that allows system designers to directly trade fault-tolerance for bandwidth, or vice-versa, in an encrypted privacy-preserving framework.

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Why is it important?

To the best of our knowledge, this is the first work that addresses the problem of communication technology migration in terms of system safety and fault tolerance. The formal framework we present aids system designers in the comparison of different communication networks and the exploration of viable fault-tolerant mechanisms. The presented framework builds upon existing model checking and safety assessment tools, and is plug-and-play, making it fully COTS compatible. As a proof of concept, we formally model the ZigBee protocol and demonstrate analysis of a hybrid network using ZigBee for its wireless protocol. We propose additions to the ZigBee protocol that enhance the reliability and trustworthiness of wireless communication, while ensuring real-time deadlines are met. The new format adheres to existing ZigBee standards, and can be used with COTS equipment. These modifications give the wireless system the ability to alter fault-tolerance and throughput capabilities in response to changing conditions on the aircraft.