GPWS, particularly EGPWS/TAWS as these systems fully utilise technology – computation, data, displays, and audio-visual alerting.
Although similar to ACAS and other warning systems, EGPWS is tops as it targets a natural hazard of flight – terrain. Whereas systems such as ACAS have become a necessity due to increasing traffic and commercial pressures on the industry.
Anyone care to estimate the number of lives saved by EGPWS? Whatever the number I doubt if any other avionic system can match the value.
Innovative? Who would have imagined that the basic GPWS’s of the late 70’s would now include spaceflight derived data, a terrain map of the world, significant obstacles, and runway locations with such high accuracy. Also, by using the system in training simulators, all this data is available for free, providing realistic visuals as well as the threat.