There have been a number of good comments from contributors who drive the cabs but perhaps still too little focus on what we are actually carrying, and the combat power that we may (or may not) be able to deliver with our respective choices.
My observation is that we have experienced 3 clear and irreversible trends in UK support helicopter operations over the last 1-2 decades:
- Pax have become both physically larger (body armour, patrol packs/bergans are the norm, not the exception) and heavier (the load we plan for a soldier to carry has effectively doubled, from 25kg to 50kg+: body armour, radios, ammo, water all drive this).
- The number of seats available have fallen dramatically for each existing helicopter due to Duty of Care, and the consequent increasing requirement for crashworthy - as opposed to the original canvas & tube - seats: we brought Chinook into service with a declared capacity of 44 pax, including those sitting on the floor in the middle (and it was proven to be able to carry 80+ on Op Corporate), but we now plan on as few as 30 pax for the same airframe.
- The parasitic burden of DAS compounds the issue further.
Net, the UK can no longer afford to play with small airframes and small cabins (eg UH60, NH90, AW149), IMO, no matter what the superficial attractions might be in terms of size/signature and HLS requirements (as an aside, Merlin can land on a frigate deck, so how much smaller do we realistically need?). In this respect a 12-pax cab becomes an 6 to 8-pax one (or worse) well within its operational life, an erosion of capability that we cannot aford.
This would point to focusing on Chinook and Merlin only, with AW159 Future Lynx, since we are now contractually bound to take it, used for carrying very small numbers of pax only, probably largely in a liaison role. In addition, a reduction in the number of airframe types were we to phase out Sea King and Puma and focus on the remaining two large airframes could actually improve our ability to support the remaining fleets on the (long-term) campaign basis that our Lords & Masters are now planning for.