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ILS Deviation Bug

PostPosted: Tue Nov 28, 2006 4:10 pm
by dir
I've noticed there is an unexplained ILS deviation about 5-10d out... is this a known issue (bug)?

My guess is it's a deliberate bug to keep you working at the ILS all the way down.

It's unrealistic, and annoying... anyone got a cure?

dir.

Re: ILS Deviation Bug

PostPosted: Tue Nov 28, 2006 6:59 pm
by Nav
Is there any wind?  :)

Re: ILS Deviation Bug

PostPosted: Tue Nov 28, 2006 11:56 pm
by Brett_Henderson
Confusing question. If you mean that the CDI deflects in the wrong direction; that sometimes happens for real, when you reach the outer limits of an ILS, for some reason. As you get closer, it flips over.

If you mean the ILS path is "off" of runway heading.. that too can be realistic. Some ILS are "offset" and have you approach, slightly off runway heading, due to obstacles.

Re: ILS Deviation Bug

PostPosted: Wed Nov 29, 2006 2:56 am
by SkyNoz
Might be Magnetic variation, I have done some looking, but can't exactly remember how it affected the ILS deviation.

Re: ILS Deviation Bug

PostPosted: Wed Nov 29, 2006 9:06 am
by dir
I should have been more specific.

The azimuth lobe of the ILS should be constant throughout the procedure. If blindly followed the 'bug' causes ground track to be 's' shaped.

This 'bug' happens with approach fully stabilised, with no wind (or other factor) set--and when completely sober. ;D  

Some CDIs/OBIs have a "To/From" flag, which reverse over the beacon. An ILS isn't a beacon though.

Anyway, I've learned to ignore the false indication now.

Re: ILS Deviation Bug

PostPosted: Wed Nov 29, 2006 9:12 am
by Brett_Henderson
[quote]Some CDIs/OBIs have a "To/From" flag, which reverse over the beacon. An ILS isn't a beacon though.

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 5:13 am
by dir
I have many years experience in real IFR flying.

I have never had a "flip" indication on any VHF navaid as you describe, vectored or otherwise.

I have however, noticed just that "phenom" in (desktop) flight sims.

Thanks for trying to help, but the effect I'm referring to is a just subtle azimuth wobble.

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 7:21 am
by commoner
...Sorry to hijack your post dir but thought you might have the answer to my query here as I know you are interested in this plane.........any one else's knowledge would be appreciated........on this Cessna 310 the nav lights are shown at the rear of the wing tanks as downloaded...but all pics I can find show them as in the bottom a/c...at the front...........any thoughts on that please..........commoner ;)

Image

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 10:18 am
by wji
" ...Sorry to hijack your post"
That's o.k. with me, Commoner . . . sounds like this threads gone into an endless loop, anyway . . .   ;D

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 11:31 am
by commoner
" ...Sorry to hijack your post"
That's o.k. with me, Commoner . . . sounds like this threads gone into an endless loop, anyway . . .   ;D


...cheers wji.....but what about the a/c?...no idea?........commoner  ;)

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 1:05 pm
by Brett_Henderson
I have many years experience in real IFR flying.

I have never had a "flip" indication on any VHF navaid as you describe, vectored or otherwise.


I have, at least twice. Once flying into KOSU, ILS 9R. It was a long, straight-in approach, and at about 18nm out, the outer marker NDB showed me quite a bit north on a runway intercept, while the CDI showed me as just south. Then.. just like magic.. boom the CDI aligned itself properly.

It made an impression on me, as I had remembered that happening in FS9..

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 1:22 pm
by Brett_Henderson
Commoner... I'm with you, as I've never seen them anywhere but up in front of/underside of the tanks. I'm not sure if that answers your question. We have a 310 in the club and I'll make a point to examine it, next time I'm out there.

If you're asking how to change it on that model. You can position the light "effect" anywhere you like:

[LIGHTS]
//Types: 1=beacon, 2=strobe, 3=navigation, 4=cockpit            
light.0 = 3,  -3.03, -18.11, 3.58, fx_navred
light.1 = 3,  -3.03,  18.11, 3.58, fx_navgre
light.2 = 3, -21.45,   0.00, 1.95, fx_navwhi
light.3 = 2,  -3.33, -18.31, 3.58, fx_strobe
light.4 = 2,  -3.33,  18.31, 3.58, fx_strobe
light.5 = 1, -21.52,   0.00, 7.40, fx_beacon
light.6 = 4,  -2.24,   0.00, 2.20, fx_vclight

This paragraph is from the aircraft.cfg file.. The three numbers after the "type" are X,Y,Z  coordinates.. where X=longitudinal, Y=lateral and Z=vertical..  All from the reference point.

Now.. if a housing and lense are already modeled, you cannot move them without the original model's source code.

You probably already knew all that, but it can't hurt to have it re-posted..   :D

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 2:18 pm
by commoner
....mmm.... thanks brett but I had already done that as you can see on the pic..There's no actual lens shown so just guess work really.I'd love to hear what you actually see at your club though.............thanks again....commoner ;)

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 2:39 pm
by Brett_Henderson
Yeah   :-[   I figured you knew how..  lol

Re: ILS Deviation Bug

PostPosted: Thu Nov 30, 2006 3:35 pm
by dir
The lower a/c is correct commoner. The strobes are encased in the same housing too. If I can find one, I'll post a pic for you when next I hit my hay :)

The majority of my flying has been above "injun territory" Brett, so perhaps that explains the higher incidence.

dir.