And in some some aircraft, the commonality is surprisingly large. You are focusing on R&O as opposed to brand new spares which is generally the larger parts count. For R&O, there is a standard T&C clause that does not allow the MoD to use secondhand parts without express permission. In EASA and European fleets the pool is often shared with lifing factors applied. Additionally, civil support tends towards power by the hour agreements which focuses on maximising availability not minimising financial loss.
Last edited by engineer(retard); 5th May 2017 at 11:23.
Reason: Autocorrect typos