smudge,
it has happened more than once that one of the 5000lbs tensioners has fallen out of the stowage in flight with the ramp and door open. If you recall said stowage was up on the fuselage wall on the left as you look aft.
Whilst we are on the subject of airdrop. I think these were a Rickman motorbikes being trialled for the special forces. Hopefully someone may know for certain.