Hi Flip
The improvement in the Puma design resulted from upgrades to the engines and later re-engining. Although similar variants to the RAF one continued to be sold in that decade, once the North Sea got hold of it for use out there, the re-engined version had a much changed/improved engine rotor governing system. Such "Super Puma" variants included the new Makila engines and associated rotor governing system. The RAF has seen none of this, despite several aborted attempts over the decades to fund either upgraded engines or replace the fleet with the latest "super puma" variants. The Mk2 upgrade programme is on-going as we speak, and includes the new engines and associated rotor governing system - so at last the system will be where it should have been circa 1980.
Cheers
