As I say, been out of the line for 15 years...
now I think about it some more - it was something to do with the RR big fans. we had accurate scale drawings of the engine in the stand and from the stand reference we could identify which version of engine/stand combination we were being asked to move. made a diffrence as to whether would fit in a 10/16/20 foot pallet & whether needed to go crosswise in the a/c.
But it was all so long ago on another planet where it was all still fun & profitable...