Because the Minister quoted in the report chooses to (quite correctly) use a fuller definition of interoperability, as opposed to merely cross-decking. It doesn't say it decreases, it merely says the idea that interoperability would be increased was incorrect.
The definition they have chosen to use means being able to refuel, service and re-arm aircraft from other nations in a combined force. Something that we have not done for fixed-wing since the USMC Harriers embarked on a CVS some years ago. That worked because their squadron embarked with them. I suspect the definition of interoperability that "was incorrect" used here refers to being able to seamlessly swap decks, which is of course highly unlikely. The HH60s on Ocean during Ellamy were again embarked with a det of support.
Other than that, when you see (for example) shots of US F4 and A7 on Ark, or F4K on US carriers, they're not doing much more than gas n'go.
There will be specific to type ASE, IT, munitions and all sorts of other paraphernalia that would be required for true interoperability. It can be done, but only as a planned serial with a lot of preparation and training - assuming classification issues can also be overcome. Whether the tales that Dave C can't recover on CDG are true or not, I don't know, but I suspect what they mean (if true) is that it can't recover at high weights, which is different to not be able to operate.
The primary rationale behind the switch to Dave C and CTOL was to reduce the risk that Dave B would get canned - that model specifically had been put on probation at the time. It would have allowed fall-back options if Dave as a whole got binned and would have allowed embarkation of US or FR squadrons as a pre-planned serial only. But I don't think we're allowed to say that now........
It is interesting that the evidence session in the Appendices sheds no more real light on how the costs escalated - nor how looking at conversion managed to cost £100M for that matter! If you ignore Docherty grandstanding, it's clear no-one really wants to get into much detail or specifics. "Additional equipment for cat n trap" can only mean Fresnel lenses, JBDs and potentially JPAR. Can't really see that lot going above 2 digit £M either.
But, it's done. It's not changing unless B is binned. Move on.
Last edited by Not_a_boffin; 5th Feb 2013 at 14:52.