Dunno how we define our servicability rate in australia but in france it looks to be if it can carry out it mission in 6 hours, its servicable
In the UK we had some very interesting definitions and very different ones for AVAILABILITY and SERVICEABILITY, but it never ceased to surprise me how many people could mix them up. They may have changed since my time though.
AVAILABLE was defined as being in the forward fleet, ie not in depth maintenance or modification and was usually a contracted output from industry (assuming industry were conducting depth/depot maintenance, as they were for most major fleets after DLTP)
SERVICEABLE was defined as being ready to fly a sortie (for the planned role) or being capable of being made ready in a certain period. This was usually the responsibility of the front line command and depended on lots of factors (role equipment, spares, reliability, tools, maintainer SQEP and numbers, command priority, tech information, infrastructure, GSE, ASSE, etc), many of which were outside of the ability for industry to deliver. Hence, industry was almost never held responsible for SERVICEABILITY rates (except for contracts like DHFS).
We didn't much bother with RELIABILITY rates, ie how often did it COMPLETE its planned tasking, which used to surprise me; especially with some of the helicopters fitted with complex mission kits.
ISTR that serviceability (measured as a %age of the departmental (whole) fleet) used to average somewhere between 35-45% (regardless of type, age, role or support contract), forward fleet average serviceability was usually around 50%, but deployed serviceability rates were usually in the 70-90%. As ever, "statistics and damn lies" can be made to answer pretty any question how you want it to look!
Hope this helps. Best of luck to the Aussies with their H-60 plans
Nick