Didn't I read somewhere that half of the problem was the way the contacts had been written for the AEW 3, one Major problem they had was getting all the software to run on a minuscule hard drive where the simply and expedient cure was to upgrade the capacity of the hard drive, but with a infinite budget they continued to spend millions trying to get the software to fit on the drive.
Not just the computer... virtually the whole concept of the aircraft, from the troubled radar with its appalling aerials to the slow and laboured hierarchal input HMI, was flawed. However, with the cost-plus contact given to GEC which paid all the company's research costs plus an extra (10%?) profit, then the more they got it wrong, the more money they made!