Originally Posted by
keithl
As you know, CDFA provides for "nominal vertical guidance", which can be no more than the standard ALT vs DME table - and therefore wouldn't have provided any extra protection to the accident we're discussing.
Probably true since the heli ran out of steam whilst still descending on the approach. But with dive and drive, the heli will have to level out at MDA, thus if coupled in 3 axis on VS and then ALT, a collective increase must be made on level off to prevent speed decay, whereas with CDFA there is no level sector.
Of course, not being coupled in 3 axes and especially not with VS / ALT is a good way to stay safe, but CDFA seems to be another string to that bow.
One has to wonder if, flying a pretty straightforward NPA is beyond some pilots's capabilities (thinking of the accident stats posted earlier, not this specific one), then how would they cope with the harder bit - getting in to the runway when suddenly becoming visual near the MAPt of, say, a VOR half way up the runway whilst still at the MDA and doing say 100kts.
I don't really see the argument against CDFA?