OK, DFC acknowledges I have some basis for my argument, Mono recognises I have some experience. I’m glad we’ve moved away from the exclamation marks and have a rational atmosphere. I’m going to try one more time to make my case, then quit before this gets obsessive. Even taking the time to write a reply as long as this shows it’s getting a bit out of proportion…
I think we’re all happy about the ILS case. As I said originally, here it does matter which way round the arrow goes. Setting it to the Inbound, Front Course, ILS QDM gives you a correct Horizontal picture whether you are going Outbound on LLZ, Inbound on the ILS, or even using a Backbeam (Back Course) signal.
Now the more contentious VOR. Flight Systems vary. Some have gimmicks like a “Reciprocal” switch, some don’t, and anyway the original question was about the HSI alone. So lets set the System aside. It’s just you looking at your HSI. Fully serviceable. Not an OBS. Not an RBI. Nor yet a bl**dy Astrolabe! Sorry. Exclamation marks, sorry. Regains poise and continues… The To/From flag always points to the VOR. The CDI may be aligned either way without affecting that. All agree? Ah, someone doesn’t. Captain S. Very well, gentlemen, everyone get out their SID Plates and look up the Grice 4D from Edinburgh. You don’t need to book a sim slot, try this on RANT, Jepp FlitePro or even (if your eyes are good enough) MS Flight Sim. Approaching the TLA 351R from the direction of St Abbs ( from the East, if you don’t have the chart ), we set the CDI to 351 or to 171. Either way, the to/from flag points to the left, towards Talla, and the BB is away from us, towards the top of the instrument. Why, I hear you ask, would I want to set 171? I’m going to Grice. Well, maybe you have a personal convention that the arrow always points to the station. That would be consistent with the ILS case and you like to remind yourself that you are going outbound by having the yellow arrow pointing behind you. It also means that whether you are flying a CDI or an RMI, Outbound is always up the tail of the needle. Others may not like such a convention – that’s fine, I leave it to you. My case is that it doesn’t matter. So you turn right, towards Grice, putting the To arrow behind you. If the APs confused, use the heading mode, but YOU have no reason to be confused.
Capt S, I have no quarrel with the view that you use everything you’ve got to maintain situational awareness. I just don’t think that meets the terms of the original question, which I took as an academic one about the HSI alone. I do disagree with your contention that “when the BS hits the ACD, SA goes out the window”, but we won’t (for space) take it up here.
Finally, I may have caused those exclamation marks by saying that something in aviation “doesn’t matter”. We all know that “flying is inherently safe, but very unforgiving of any carelessness or error”. So I agree, everything matters in that sense. When I use the phrase “doesn’t matter” in this context I mean, “will not cause disorientation”. If you still think it will, then we must agree to differ.
“Keithl Out.”