The Block 40/45 Mission System Upgrade is the largest in the history of the AWACS programme. Building on earlier Block 20/25 and Block 30/35 efforts, the Block 40/45 is essentially a mission computing systems upgrade that covers hardware, in the form of a new suite of current state-of-the-art flat-screen computers, as well as the necessary software. This takes the aircraft very much into a Windows type of environment, enhancing the system’s networking capability while improving the aircraft’s reliability and lowering life-cycle costs.