Well spotted Duff!!
It's the sounds taken from the FS2002 Bell UH-1H Huey By Jordan Moore.
The sounds included were created by Manuel Gonzalez, who in turn took those high quality recordings from a real-life Bell 212 (Civilian Designation for one of the UH-1 Huey series).
The sounds are 100% Freeware, but the readme file states that if anyone wants to use them in an addon and re-distribute it 'etc', due credit should be given to the author, or at least include his name in the readme file, lol
But I have to agree with you Duff, they're pretty d@mn good and I've used them myself for the Special Forces UH-1H.