SK and Whirlwind are out of service I'm afraid, so all 6, 8, 12 tonne helicopters in the 2020s are going to have sh1tloads of downwash and we're all safer in the air because of it. Realistically, not just S-92 have downwash issues and there have been downwash incidents with 135s. There has been some recent research going on about downwash and the effects on loads below the aircraft and a pattern has been emerging related to the aircraft weight, rotor disc area, and air density. More work on this is expected to produce something worthwhile that can be added to a RFM near you in the future.
189 has performed well and done jobs far out to sea that some might have expected would be solely S-92 territory. I haven't seen any specifics about the economics but it's not hard to imagine a significant cost margin between the types. With the 189's speed, range and payload there may just be no need to pay for a S-92.
Scotland will be an all-189 territory and there is not much to complain about with that. The S-92 has been described as a very stable winching platform in challenging mountain conditions and for large searches one might imagine it deploying more MRT. Realistically though, there's not really much difference overall.
What does surprise me is the number of 139. It has been described by paramedics as not having enough room for them to do proper work on a patient. Some of us may have heard that complaint about Merlins from people used to Chinooks but once you get down to the size of the 139 and there is a long flight back to dry land I think I can see how it could be difficult to keep a seriously injured patient alive and stable. Having said that, there is BHL data available from operation of 139 at Lydd and St Athans 2015-2018 and of course CHC at Portland and Lee-on-Solent for 10 years up until 2017.
The current contract, although very good, has to some extent been a quick-fix, one size fits all, sort of a spec. That came about after the collapse of the PFI. I can see from the way the spec was laid out from the very start that UKSAR2G is far more aligned with the real data that has been collected since 2015. Even on the PFI, this quality of data wasn't really available since, as the NAO pointed out many years before, the MoD and DfT were not measuring the same things and did not co-ordinate their statistics.
Last edited by jimf671; 10th December 2022 at 11:07.