Gentlemen
Many thanks for the info. Aviation certainly has moved on in ten years. I had assumed that RNAV meant GPS and had no knowledge of DME/DME fixes. I'm not too sure how they would work so must do some research.
Interestingly North Sea nav, (I'm ex BAHelicopters, mainly S61 and the commercial Chinook) was all RNAV using Decca either with the moving map or with Danac where we had ten whole waypoints to use. About '95 we moved on to GPS but only as a secondary aid. IBC's in the sim were of course all airway-based, allsame as fixed-wing.
Not surprised to hear that Loran and Consol have gone. During one interminable North Sea leg I once managed a Consol fix, plus or minus 20 miles.
Can I have just one more query. My interest in RNAV comes about through the gift of X-plane simulator for my Mac. Could you tell me what a typical rate of climb might be for, say, a 737 on take-off, also during a standard climb on the airway and a standard descent
Once again, many thanks for the response, I'm obliged to you.