CDI in ILS/TCN or ILS/NAV mode
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If I’m in either ILS/TCN or ILS/NAV mode, is the CDI in the HSI representing deviation from the ILS localizer signal or deviation from the TACAN signal or deviation from the Steerpoint?
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@jc1:
If I’m in either ILS/TCN or ILS/NAV mode, is the CDI in the HSI representing deviation from the ILS localizer signal or deviation from the TACAN signal or deviation from the Steerpoint?
Hi there mate.
Well when you are on ILS/TCN or ILS/NAV mode, the CDI gives the Localizer deviation.
When you are on TCN or NAV mode, the CDI gives the deviation from the selected course.
Nikos.
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Hi there mate.
Well when you are on ILS/TCN or ILS/NAV mode, the CDI gives the Localizer deviation.
When you are on TCN or NAV mode, the CDI gives the deviation from the selected course.
Nikos.That cleared things up for me, a lot. Thanks mate.
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ILS/NAV is it only useful where you have the airbase as a STP and there is no TACAN on the Air Base but it does have an ILS beacon ?
Does this mode have any other navigational uses?
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That is its operational mode, I was just wondering when it would be utilised in flight? is its use restricted to the one I mentioned in my post or does this particular mode have other “uses” ?
Thanks for the table - it is useful.
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Depends on what you want to do I guess, and what is available for navigation or at the airport.
Personally I mostly use it as this:- default NAV
- SID, high level TCN nav, TCN approach: TCN because there the DME and CDI should be in relation to the TCN station
- TCN to ILS: TCN for holding and DME arc; and once turning out the DME arc to intercept localiser switching to ILS/TCN or ILS/NAV. Mostly ILS/TCN in case of missed approach, when the published charts speak of DMEs in relation of TCN.
- Straight in to ILS: ILS/NAV
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So it is only useful for straight in ILS approach where the air base is set as a STP - many thanks.
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So it is only useful for straight in ILS approach where the air base is set as a STP - many thanks.
I’m not saying that
I’m just saying that’s all I use it for now. But more experienced guys might give other answers on this. -
Cheer FD
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That is its operational mode, I was just wondering when it would be utilised in flight? is its use restricted to the one I mentioned in my post or does this particular mode have other “uses” ?
Thanks for the table - it is useful.
Hello mate.
Well the only situation that can be used the ILS/NAV (as only) I think is when the TACAN station is a little far away of the RWY of the airport and there is a small obstacle (small hill maybe) that gives interference and can’t have a “steady” receiving signal from it (means the TACAN station) in order to know your DME while executing the ILS approach.
So knowing the GPS coordinates for the TACAN station, you can manually insert them over an STPT and execute the ILS approach via ILS/NAV ;). This case is for Falcon.
If the airport has no TACAN station, it has no real meaning (means not mandatory) to use the ILS/NAV, because it can’t give you the benefit of the DME. You can also use the ILS/TCN (same as the ILS/NAV in this situation), since you are gonna have an ILS approach and not an ILS/DME one!
Nikos. -
BMS Dash1
The top knob is a four position knob setting the instrument mode: ILS/TCN – TCN – NAV – NAV/ILS.
• ILS/TCN - one of the two modes used to display the ILS needles. It activates the ILS symbology in the HUD, the ADI and the HSI. The course deviation indicator on the HSI gives the localiser deviation The TO/FROM indicator is not displayed and the bearing pointer points at the active TACAN station. The range value in the DME window of the HSI is from the active TACAN station and not the ILS. .
• TCN - the HSI displays course deviation and distance from the active TACAN station. ILS symbology is not displayed. All HSI indicators point to the TACAN station. The TO/FROM indicator is displayed.
• NAV - the HSI displays course deviation and distance from the steerpoint of interest (active UFC Steerpoint) and not the TACAN. The TO/FROM indicator is displayed.
• ILS/NAV - ILS symbology is displayed as in the other ILS mode in the HUD, ADI and HSI. The course deviation indicator on the HSI gives the localiser deviation, the TO/FROM indicator is not displayed, the range in the DME window is given to the steerpoint of interest (and not the ILS) and the bearing pointer on the HSI points to the steerpoint of interest as well.one thing to rememeber, the DME is never the ILD DME, it’s always either the TACAN or the STPT.
these two can be away from the runway threshold at a certain distance.if you have a steerpoint on the airbase you’re landing, you can use ILD/NAV to get DME from that steerpoint
Red Dog
Reality if for ppl who can't handle simulation -
@Red:
BMS Dash1
if you have a steerpoint on the airbase you’re landing, you can use ILD/NAV to get DME from that steerpoint
Well if that airport hasn’t (or can’t has) a published procedure (means no TACAN/VORTAC station there), then it can’t actually offer any help the DME from that STPT. Also you are not sure where exactly is that STPT in relation with airport RWY (how far from it as also at which angle of RWY) ;).
Nikos. -
Well, one can argue that if you want to calculate your slope - albeit approximately - knowing the distance will help
But anyway, it’s pretty volatile and imho knowing the distance is always better than not. but indeed you might not always have a need for it.
the point was rather to emphasize that there is no ILD/DME in Falcon; DME always is to the TACAN or STPT, never to the ILSRed Dog
Reality if for ppl who can't handle simulation -
Can use the NAV mode if your TACAN has failed and you do have a steerpoint at the TACAN coordinate. Technically not legal I guess but it’ll work.
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@Red:
the point was rather to emphasize that there is no ILD/DME in Falcon; DME always is to the TACAN or STPT, never to the ILS
We agree on that for sure, in Falcon world :p.
I hope someday to we can have the DME independent from the bearing (e.g. to can have only the DME from a VOR/DME station) as also the ILS Loc and GS…
Nikos.
