LOC WILL BE TUNED (not ...)

[bpcw0001]

Hi,

I've come across some occasions where the autotune of an ILS just would not happen. I had to disengage and make a visual approach last second.

Among those where: EGGW ILS 07 (VECTORS) and LIRA ILS Y 15 (via LOCRI).

Navigraph data, the charted ILS frequencies definitely work when tuned in manually.

Capt nav sources were FMS1, preselected LOC1, and FO nav sources were FMS2, LOC2 preselected at all times (since I've read that not having this may cause issues with autotune).

Autotune usually works for me, but then, there are these occasions when it just doesn't.

What's the deal here? What might I have overlooked?

[Pils]

Firstly, may I suggest this video: https://www.youtube.com/watch?v=dvQsqCypHCg

Secondly, the most common reason is the off-side nav source not being in FMS as you suggested, so it's good you checked that. There's also a scenario where if one manually tunes the localizer frequency before entering the terminal area, and switches back to AUTO, then the setup may not complete successfully.

If an appropriate approach is selected and FMS is the nav source then this setup should happen at ~31nm from the destination, and that's when you'd see the "ghost needles". There could always be bugs in this process.

Maybe you could reproduce a specific occasion and record a video of the approach, FMS setup, etc.? Please also provide full flight plans.

Edited July 16, 2023 by Pils

[bpcw0001]

Oh boy ... I missed the radios no longer being set to "AUTO" tune after manually tuning in some VOR.

Thanks for the heads-up though. Good video in the link.

A lot of things to learn with this marvellous bird, our Challenger.

Edited July 16, 2023 by bpcw0001

[Pils]

2 hours ago, bpcw0001 said:

Oh boy ... I missed the radios no longer being set to "AUTO" tune after manually tuning in some VOR.

It's OK for them to be in MAN, that's what the LOC WILL BE TUNED message is for, to remind you that the FMS is going to retune the radios.

[bpcw0001]

16 minutes ago, Pils said:

It's OK for them to be in MAN, that's what the LOC WILL BE TUNED message is for, to remind you that the FMS is going to retune the radios.

Hm ... ok. Strange then. Then I am not even doing anything wrong as it seems.

Also right now, I was going along this route:

LIRA/15 N0466F390 ESI5V ESINO Z924 ABIDU DCT EPIKU DCT GINOX UM601 BCN UN975 CCS DCT ELVAR DCT EXONA EXON9A LPPT/02

On approach to LPPT, I came along the EXON9A arrival, the ILS starting at PESEX. The ghost needles appeared very late, between PT422 and PESEX, where the ILS glide commences.

So the auto tune happened, but a bit too late for comfort, basically seconds before the capturing the glide slope of the ILS. Had this happen on other occasions as well, when the ghost needles and the auto tune happened very late.

 

[bpcw0001]

Same on arrival / approach into LEVC RWY 12:

Arrival SAURA.SAUR4D, approach ILS Z RWY 12 via OPERA

Autotune and ghost needles happened at around OPERA only.

Like I said, still sufficient, but a bit late for comfort.

 

Many other approaches give me autotune and ghost needles way before the actual approach.

 

 

 

[bpcw0001]

Came across several more occasions of autotune/ghost needles not working/showing up. It remains somewhat hit and miss for me, even at the same airport/approach (e. g. LIRA), and even if the procedure is always the same (Capt and FO nav sources carefully checked to be FMS1/FMS2).

I'm quite at a loss here and resorted to pre-setting ILS frequencies and courses in case the autotune does not kick in.
No big deal, but not really as it is supposed to be.

Edited August 8, 2023 by bpcw0001

[Pils]

And the PRESELECT NAV is VOR/LOC on both sides? I think it might help if I saw a video of some approaches being done that have issues.

[bpcw0001]

4 hours ago, Pils said:

And the PRESELECT NAV is VOR/LOC on both sides? I think it might help if I saw a video of some approaches being done that have issues.

Yep. Preselect is always VOR/LOC for both sides. I go to great lengths checking this since I understand its importance.

I'll see if I get something reproducible.

[FYG001]

Personally, an that is also the way our CL650 Pilots do it, I have always the frequency and course preset, so that if the transfer doesn’t happen automatically, I can do it manually. 

[bpcw0001]

36 minutes ago, FYG001 said:

Personally, an that is also the way our CL650 Pilots do it, I have always the frequency and course preset, so that if the transfer doesn’t happen automatically, I can do it manually. 

Yeah, there's also been some older discussion over at pprune with people discussing the somewhat unreliable/unpredictable behavior of autotune and nav-to-nav transfer in the real-world Proline system.

Seems the HS Challenger simulation is spot on even here 
That stuff seems to be quirky in real life as well.

With the knowledge that the system does not work any better in real-life, I can well settle with it being the way it is. 

Edited August 9, 2023 by bpcw0001

[bpcw0001]

I've been observing the behavior now for many, many flights after my initial post here, and after I've adjusted the way I set up my flight plans.

I haven't run into the issue of a missing auto-tune and NAV-to-NAV transfer since.

It appears that the system is prone to not do the tune and transfer properly if e. g. the first fix of a vectored approach comes directly after an en-route waypoint.
If a discontinuity is left after last enroute waypoint and the first approach fix, tuning has never failed for me.

Same if a non-vectored approach comes directly after an arrival procedure without discontinuity.

So it's most likely me not having done things properly in the beginning.

Edited September 9, 2023 by bpcw0001