Timothy wrote:
Thank you for the sarcasm re disgruntled airlines.
Hopefully no harm prevails.
I meant that the airlines don’t act out of disgruntlement or envy but are a dominant stakeholder, they know how to lobby, and they do it because of cost vs. benefits, and don’t care about the other stakeholders like private GA.
In any case, ppl/ir is doing a very impressive job, thanks!
JasonC wrote:
Other than the VABIK departure are there other RNP (not AR) procedures with RF legs in Europe?
Sorry, I missed this.
LFST 23 and 05 RNAVs. These are what I used to test the way the GTN switches procedures on an off as you switch RF legs on and off. There may be others.
chflyer wrote:
Sorry if I’m not sympathetic,
I was not touting for sympathy for the airlines, merely reporting that some of them squeal when RNP and/or RF are introduced or proposed.
The argument against removing support for older technology has merit, but not that new facilities should not be allowed if they disadvantage companies unwilling or unable to take advantage of the benefits (track miles, time).
The arguments for PBN include reduced infrastructure costs, reduced air miles, more efficient use of airspace and reduced requirement for ATC intervention. All of those benefits are lost is you keep the legacy technology. That is not a statement of my credo, simply a statement of fact.
Therefore, there is strong pressure for “everyone” to be able to use the new technologies, as a matter of mandate. This has been seen in PBN, 8.33, Mode S etc.
There are two scenarios which are entirely imaginable:
So you can see why operators, PT and private alike, might be resisting all moves towards RNP1 and RF, seeing them as the thin end of the wedge.
but that point is essentially a question of business decisions regarding competitiveness, which is not the same as the GA arguments about regulations that add an unavoidable cost burden just to keep flying. Every airline needs to constantly make a tradeoff between continuing to operate existing equipment vs upgrading vs investing in new planes. I see no reason why companies who are ready to adapt new technology that benefit themselves and the customers should be held back by those who won’t or can’t.
The decisions being taken might prevent some aircraft flying, including older airliners and a swathe of GA aircraft, though GA is in a stronger position because we can generally buy-in the technology at relatively low cost, whereas there may never be STCs for some legacy aircraft.
I am not really discussing the rights and wrongs of the argument, just laying it out.
What is the purpose of the RF legs in your examples? Even in my anemic Aztec I will be above 2000ft in the climb out from R23 when I reach ST420 and the highest ground in front of me is 1184ft. Looking at the map for the area it doesn’t seem to have any noise implications so why not just have a fly by waypoint and a direct to ST430? I dont know the area so although having flown into Strasbourg several times others may have a better view of the noise issue.
Similar issues for the other RF leg on the go around which is turning away from Strasbourg City.
It almost seems like a plate designer looking for opportunities!
JohnR wrote:
What is the purpose of the RF legs in your examples?
I think the question needs to be turned round. You will have seen my analogy in the PBN Manual that the available legs can be thought of as Lego blocks. The procedure designer has a limited choice of building blocks and he builds using them.
If he wants to build a curve, he can build it out of a number of straight segments, or he can rely on the fly-by capability of the navigator, but why would he build this:
When he has one of these right under his nose.
So the question becomes “why wouldn’t he?” and the answer is “because many aircraft cannot yet fly them”, hence the catch up games between IFD and GTN, the obsolescence of the GNS, 155, KLN etc and the lobbying by the airlines.
JohnR wrote:
It almost seems like a plate designer looking for opportunities
Which one you want the Architect or the Engineer 
Yes I can see your logic but in his instance I cannot see why it makes the design of the procedure safer, less noise intrusive or more efficient. However, if my GTN can have the RF facility turned on I will happily use it!
JohnR wrote:
I cannot see why it makes the design of the procedure safer, less noise intrusive or more efficient
That’s not the point. He wants a track reversal through 180° to another track a certain distance away. Why would he use an ugly bunch of short straight legs when the answer is staring him in the face?
Look at this Point Merge procedure:
Isn’t that pug-ugly, wasteful and just annoying compared to a beautiful, smooth silky RF leg? 
Incidentally, I hope that the Lydd ILS overlay could now be coded. At the moment it is just not there, presumably because the DME arc is too difficult to code, made simple by an RF leg.
The Lydd ILS is on the KLN94 but the DME arc is not shown. Only the localiser bearing line.
Why would he use an ugly bunch of short straight legs when the answer is staring him in the face?
Because there is no practical difference by the time a plane is flying that route, and it saved spending loads of money on avionics.
Same argument with MLS. It was a very ideologically pure concept.
