A CL44 was being loaded in DXB years ago with gold bars; the loaders, one by one, carried 1 bar each (about 10Kgs, I think) up the forward stair and walked down the fuselage to the rear, where the bars were being distributed on the floor moving forwards, placed the bar and exited down the rear stair to get another bar.
The loading plan was that by the time the last bar was in place, the load would be evenly distributed along the whole cabin, each side of the CoG. The one-way system would be time-and-effort-efficient. We forgot to think about the interim stages of this otherwise excellent plan.
You're there already.......at the moment when the load aft of the CoG reached a critical point, a loader started walking aftwards from the front with his bar and, as he passed the CoG the nose, ever so gently, rose off the ground. The loader, now going downhill, increased speed.......so did the vertical speed of the nose.......
All the bars loaded by then, several tonnes and not yet fastened down, slid with increasing velocity to the back.
And someone had forgotten to attach the strut.