Flight-critical information for IFR flying includes attitude, heading, airspeed, and altitude. Navigation information is high on the needs list but is not as critical as the previous items. The same is true for communications. The criticality generally follows the doctrine of aviate, navigate, and then communicate. Likewise, the FAA system safety analysis (required for equipment certifications) places the highest criticality requirements on attitude, heading, airspeed and altitude.
Here, I’ll first explain how the flight-critical data is generated in today’s digitally integrated cockpits, possible failure modes, and then I will dig into possible propagation of a failure across other functions in an integrated system. Last, I will discuss recommendations for handling the situation.
