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I believe the statement that the long bodied (-1,-50,-100,-150,-200s) were all built with the analogue AFCS would be correct. The -250 I think only had 524 engines and uprated wing stucture to give higher zero fuel weight and more fuel capacity."
The 524B02 engines were fitted to -200 and -500 series a/c BA recieved, the -500 524's were uprated to the B4 series when the 4.5 feet extentions were added to the wings, along with the active aileron system, this was carried out as the delivered aircraft had a range shortfall. I also remember that Gulf Air uprated some of there -100 to -200 series, part of the mod was to uprate the engines from the 22B's to 524B2 series engines.
But this was all so long ago, and many happy memories of a great aircraft.