ILS in Comet

[Jakemaster]

Hello all, been a while since I posted here.

I downloaded and flew DM's new comet yesterday (FANTASTIC by the way), but noticed one problem. On the ILS gauge the glideslope doesn't seem to work. I tune an ILS frequency and the localizer comes alive, but the glideslope doesn't move. I flew an approach using the GLIDE mode on the autopilot and the autopilot flew fine, glideslope and all, but the horizontal bar wouldn't budge. Maybe I missed something in the documentation.....anyone know why my glideslope doesn't work?

Thanks

[Sl4yer]

I downloaded and flew DM's new comet yesterday (FANTASTIC by the way), but noticed one problem. On the ILS gauge the glideslope doesn't seem to work. I tune an ILS frequency and the localizer comes alive, but the glideslope doesn't move. I flew an approach using the GLIDE mode on the autopilot and the autopilot flew fine, glideslope and all, but the horizontal bar wouldn't budge. Maybe I missed something in the documentation.....anyone know why my glideslope doesn't work?

I noticed this on my brief flights. This is in the documentation (regarding the ILS gauge):

Note that this indicator only displays information from the opposite NAV radio to the one selected on the SFS Radio selector (centre panel).

I'll give it a try and see if this solves it. I suspect it will!

James

[Jakemaster]

I downloaded and flew DM's new comet yesterday (FANTASTIC by the way), but noticed one problem. On the ILS gauge the glideslope doesn't seem to work. I tune an ILS frequency and the localizer comes alive, but the glideslope doesn't move. I flew an approach using the GLIDE mode on the autopilot and the autopilot flew fine, glideslope and all, but the horizontal bar wouldn't budge. Maybe I missed something in the documentation.....anyone know why my glideslope doesn't work?

I noticed this on my brief flights. This is in the documentation (regarding the ILS gauge):

Note that this indicator only displays information from the opposite NAV radio to the one selected on the SFS Radio selector (centre panel).

I'll give it a try and see if this solves it. I suspect it will!

James

Ah, I figured I missed something in the documentation STUPID Lets go see if it works!

[Sl4yer]

It does work. I set NAV2 to the ILS and the SFS to 1, and the glide indicator came to life.

Of course, I'm assuming you need to set the ILS on NAV1 and set the SFS to 2 to use the AP Glide function!

James

[MALTBY D]

I think you got this one sussed. The ILS thing always uses the NAV radio that is NOT selected.
I don't know why the Smith's Flight System was arranged like that, but it was.
I still find it quite difficult to use, and I understand it. (a bit)
Fraser's the real SFS expert. ;-)

If you can, set the ILS in NAV1 & 2 to make sure.

DM

[Jakemaster]

I think you got this one sussed. The ILS thing always uses the NAV radio that is NOT selected.
I don't know why the Smith's Flight System was arranged like that, but it was.
I still find it quite difficult to use, and I understand it. (a bit)
Fraser's the real SFS expert. ;-)

If you can, set the ILS in NAV1 & 2 to make sure.

DM

Yep, tested it and it works.

[Sl4yer]

If you can, set the ILS in NAV1 & 2 to make sure.

Yep, that seems to be the way to do it. Then you can have the ILS display active, AND have it fly the glideslope!

Much learning still to be done.

James

[ravilamir]

Hi all,

The SFS, as described by Fraser McKay for his Britannia panel, is centred upon the Flight Director as seen here:

Radio Selector.
The radio selector is used to select Nav1 or Nav2 information to the Flight System. The top switch is selected to 1 or 2 as desired. Note that the Azimuth Director and Pitch Director will only respond to Nav1 displacements so if Nav2 is selected the radial and glide path must be flown raw. When the switch is Off, the Azimuth Director will respond to differences between the Heading Pointer and Heading Index on the Beam Compass. A magnetic indicator shows the input to the Flight System.



Director Horizon
1. Beam Flag. Visible when a steady VOR/Localiser signal is received
2. G/P Flag. Visible when a steady Glide Path signal is received.
3. Pitch Director. Shows demand for pitch corrections relative to GP deviation.
4. Horizon Bar. Moves relative to aircraft bank.
5. Pitch Pointer. Moves vertically relative to aircraft pitch
6. Pitch Scale.
7. Bank Scale.
8. Azimuth Director. Shows demand for heading and bank corrections.
9. Ring Sight. Placing the Ring Sight over the Azimuth Director will correctly bank the aircraft.
10. Pitch Scale Setting Knob.

The image is this:

David
On your Comet panel the Pitch Director (no 3) is not receiving its data from the NAV radio selected on the SFS switch, as far as I can see. Please correct me if I am wrong.
It is my understanding that for ILS approach, the Glide Path is shown on the Director Horizon through the dash number 3 and the Course is shown on the HSI and the NAV radio in use is selected on the SFS switch. That's why the ILS gauge shows the opposite NAV radio. That gauge is referred by Fraser as a CDI:

Course Deviation Indicator
The CDI shows deviations from the course and glide path of a facility selected on the OPPOSITE Radio to that selected on the Radio Selector; i.e. if Nav1 is selected to the Flight System, Nav2 information will be displayed on the CDI and vice versa. It is recommended that for ILS approaches where a VOR bearing is not required, that the ILS be tuned to both radios.

Hope this helps you

[Viscount Cornbank]

That pretty much sums it up

It is possible that the Comet setup was different to that of the VC8/VC9 which had a different CDI instrument.

The pitch director(3) doesn't register at all unless the pitch scale (6) is fully wound down. Otherwise there are no ILS pitch commands or GP flag on the instrument. Although that's how it works on the panels I use, from memory its only available on the release versions of the Viscount 802/6 and the VA update of the Britannia panel.

Cheers

Fraser

[ravilamir]

Fraser

Many thanks for the extra information and also for design such superb panels!

David
The Pitch Director does indeed work, but it is hard to see it and it doesn't exactly show the ILS beam deviation until you are on top of it!

Soft Landings!