Depends on when the UK wants the type to be in service, with respect to the US the schedule is as follows
I'd imagine around the Block 3 mark myself, IIRC 617 Sqdn will stand up in 2016 as our first operational squadron so around there.
- USMC: mid-2015 with Block 2B
- USAF: mid-2016 with Block3I (originally going to be full capability block 3F in mid-2017)
- USN: mid-2018
I'd imagine around the Block 3 mark myself, IIRC 617 Sqdn will stand up in 2016 as our first operational squadron so around there.