"The RJs have been flying since the 70s. They have all gone through numerous modifications at Greenville. They have ALL gone through extensive flight systems testing at Greenville. They have ALL gone through extensive backend equipment upgrades and certifications. And, the RAF RJs are just the same as the USAF RJs. They are all considered ONE FLEET".
Like the E-3Ds you mean? Seven aircraft built in the same factory at the same time. One of the frames has different wings (believe from RC 135 with no specific routing for ESM/coms cables which were just passed through the ribs as and where - no surprize that HF comms had an affect on ESM performance). One aircraft had been hit by a vehicle during construction - the bent pressure hull was "beaten out" and declared serviceable. On insistence of QA, the aircraft tail was removed and a replacement from further down the line bolted on. There is no sign of the old bent tail which could have been fitted to a later aircraft. I could go on.....especially with an area below the floor which was full of swarf on one aircraft.