"Extended" warranty. Very common in my industry. You basically negotiate a fixed monthly (or yearly) price for the extension of all (or portions) of the original warranty terms. Ours is for parts only, as we contract with a third party for the PM and CM. Not sure it would work in a military environment, but all terms can be negotiated. In our case, we have a requirement for critical parts delivery within 2 hours of the initial demand. To satisfy this, the OEMs established stocking locations near to (or in some cases inside) our facilities. They maintain the stock, and working with us regularly review historical usage and adjust the MAX/MIN levels. I would argue it's actually a good model for an orphan fleet, as it incentivizes the OEM to make the investments needed to maintain adequate spares for the duration of the Extended Warranty period. Not even sure it's more expensive, as we were able to get out of the parts inventory/warehousing game, which has saved us millions. Don't know if this would work in DND, however, but, if we wanted to get the most out of this platform, securing another 20 years of parts would be a good first step.