BOAC and Onceapilot - thanks for the responses. I know that a proper weight/balance determination is made for every takeoff and should have caught the cg being out of range if it was. I am just trying to identify any possible contributing factors to the puzzling detail that the the takeoff heading to Bagram went off okay while the one out of Bagram led to the accident. From what I have gleamed from the discussion here, the only significant weight/balance change between these two takeoffs was more fuel for the second.
Is it possible that the weight/balance determination for the first flight was incorrect, but that with less fuel the cg was in an acceptable range? If the same, incorrect, cargo weight/distribution data was then used prior to the ill-fated takeoff it might have shown the cg to be within range with more fuel when it actually was not.