Airdrop
When we bought the original tranche of 66 Hercules the US floor was changed to a UK specific floor to allow the use of the UK roller conveyor and side guidance system (SKYDEL ) , a version of which was used on the VC10, Britannia, and Argosy. Commonality (and UK workshare ) was the rationale. The system was used for cargo and airdrop as appropriate. The US system then in use was the Brooks and Perkins dual rail system. A version of this I understand is fitted to the C130J. The UK airdrop system was not usable in the US fit without extensive modifications. I do not agree that the UK system is intrinsically superior. The US philosophy was to use cheap unstressed platforms and equipment designed especially for airdrop. The UK went for expensive stressed platforms (HSP, MSP, SSP, ULLA ) and 'ordinary ' equipment. Both systems IMHO work well.
This of course is a very simplified version of the facts