DA,
Foxtrot has been widely discussed at length here on Prune but in a nutshell, it unnecessarily complicates what should be, as an evolution of the NDB then VOR NPA and utilising the latest technology, very very simple. In my experience, it is not. This view is not held universally, obviously, and there are some quite vociferous defenders of it.
However, in my (and as I have said quite a few others) opinion, Foxtrot makes the approach more complicated because you never know, at a glance, where you are WRT the runway. You only know where you are WRT to the next waypoint. Right at the gravy stroke, probably going thru the MSA for the first time, gear going down, flap going out, scans & checklists to be done, radio calls to be made, perhaps altitude restrictions on the way down, we have a waypoint/distance reference change. Looking at the graph that was presented on the CASA website, it would not surprise me that the Metro crew thought they were past Foxtrot when in fact they weren't. Why on earth would a crew with a bunch of pax on board conduct such a "scary" approach? There are probably lots of factors involved, and IMO the unnecessary complexity of the approach itself was one of those factors.
I reject the assertion that GPS NPAs are easier than say a VOR/DME. Why? Because on a VOR/DME you have a distance reference from the top of descent/start of the approach all the way to the runway plus or minus a bit. this makes life so much easier. If it wasn't for the fact that most of our VORs are slightly offset and GPS NPAs leave you on the centreline at the MDA, I'd be doing VORs in preference.
Situational Awareness is not enhanced having the FAF as a waypoint. When all is going swimmingly, all will easily cope with a GPS NPA. Unfortunately, that is not always the case, and it is then that the "system" needs to be a simple as possible.
Perhaps in the very early days Foxtrot was needed by the technology (an argument I do not accept and never will). That is now not the case and it should be removed, providing us with only one distance reference TO THE THRESHOLD on the extended centreline from the MSA. If you don't have a VDI, then the chart would provide a simple, profile from the MSA all the way down to the MDA.
I have no doubt that those guys were brought undone in part by the complexity of the GPS NPA they were flying.
PS: I started reading the ATSB report after making the above comments.
Last edited by Capn Bloggs; 5th Apr 2007 at 06:30.