It's often quoted that to keep the VC10s in the air is MASSIVELY expensive.
What exactly (if not classified) is the source of this? Of course there's direct (such as fuel) and indirect (crew training & pay etc) costs.
I know the engines are old and thirsty, but how much more fuel efficient is an A330 vs the same lift in a VC10? Say moving 650 men 4000 miles.
Are the spares having to be specially manufactured? Tyres? I can't imagine RR have 50 x Conways in the stores, so I'm thinking they have to be rebuilt, but is that much more expensive than rebuilding a Trent? Much more frequent?
I'm not advocating keeping the 10s, just trying to understand what the costs (comparatively) are.