Was it not the Mk 6 Chinook that had been given the complete work through by the US that then came to the UK for BD trials where the TPs found a potentially dangerous handling tendency when manoeuvring hard at low level?
Perhaps they are wary of other countries claiming to have tested properly.........
I can understand that, but tens of thousands of people fly every day in aircraft that have been certified by the FAA, and this engine and all associated controls had been certified by the FAA to the same standards. There was zero difference between the way this engine had been certified to the way that any other FAA certified aircraft engine and associated controls had been certified. Other countries had already accepted the FAA certification and had the engine in service, too.
The point made to me was that the FAA certification couldn't be trusted by the UK. IIRC, the original objection was that the software inside the FADEC (really firmware, rather than software) had been written in a variant of the C language (as is the firmware in many thousands of other safety critical bits of kit) and QQ wanted it re-written in Ada. They backed off from that demand, but then insisted that they just didn't trust the FAA to have done a good enough job, despite being offered all the FAA evidence (which they refused to even look at).
FWIW this had absolutely nothing at all to do with the blatant disregard for basic safety surrounding the RTS of the Chinook. The Chinook's many safety issues were fairly and squarely the fault of Boeing and Textron, and not in any way related to either Rolls Royce or Honeywell at the other end of the USA.