#45 navradio: Airports with multiple ILS signals with same frequency not working

[Anonymous]

Originally created by: pedromor...@gmail.com

navradio: Reversible ILS –
           observed:    25 Dec 2008
           supplanted by:    bug 9
Consider the following scenario. In the Sim World, you are on the KJFK ILS
RWY 31R approach. You are at an altitude of 180 feet, centered on the
glideslope, about 1/2 mile from touchdown, i.e. just about to cross over
RWY 22L. All indications are stable. So far so good. Then suddenly the
localizer CDI needle switches from half a dot right of center to full-scale
left of center, through no fault of your own.

Evidently, the simulator has just switched the ILS transmitter from 31R to
13L, as you can confirm by listening to the ident. It does this every time,
as a function of aircraft position.

This means that in the 1.9.0 Sim World, the KJFK ILS RWY 31R is not flyable
under low-IFR conditions. I reckon the same problem arises at every airport
where there is a reversible ILS.

This is not good.

This is an old bug.

In the Real World, the active runway is determined based on wind conditions
(etc.) and the reversible ILS is set accordingly, independent of aircraft
position.

denker 7s

[Anonymous]

Originally posted by: pedromor...@gmail.com

(No comment was entered for this change.)

Status: New

[Anonymous]

Originally posted by: g...@av8n.com

Some of the symptoms of this bug were changed by
commit [r29f84492a2cdc40a3275e6ff11b4b9520f8774d9]
Date:   Wed Sep 16 09:35:22 2009 +0000

However ... the basic problems remain.  Specifically:
FG still allows simultaneous approaches to both ends of a
reversible ILS, which is just ludicrous from the radio-physics
viewpoint as well as the pilot's operational viewpoint.  The
idea that you can just show up at JFK and shoot a straight-in
approach to whatever runway is straight ahead, without regard
to winds and without coordination with ATC ... well, it's a
bit arrogant, as well as unrealistic.

A patch to do something sensible with reversible ILSs has been
available for a couple of years.  100% of the pilots who have
commented on it consider it an improvement.
  http://gitorious.org/~jsd/fg/sport-model/commits/navaid-repairs/

[Anonymous]

Originally posted by: cumuluni...@gmail.com

Set to stalled due to lack of activity. Does this bug still exist at all?

Status: Stalled

[Anonymous]

Originally posted by: cumuluni...@gmail.com

(No comment was entered for this change.)

Labels: Priority-Low

[Anonymous]

Originally posted by: h...@hyde-tech.com

Still exist.

http://gitorious.org/~jsd/fg/sport-model/commits/navaid-repairs/
This patch does not work for EBLG since it has 3 ILS and 2 has same heading.
Best way is just pilot selectable by menu.

[Anonymous]

Originally posted by: bre...@gmail.com

Yes, James was working on a more general solution, which I believe would also address airports with multiple ILS having the same frequency.

Summary: navradio: Airports with multiple ILS signals with same frequency not working
Owner: ---
Labels: -navradio -ILS Nav
Cc: zakalawe@mac.com

[Anonymous]

Originally posted by: pedromor...@gmail.com

(No comment was entered for this change.)

Labels: airport ILS

[Anonymous]

Originally posted by: h...@hyde-tech.com

James,

How is this going?
I really need the button or check box whatever to enable only one of the ILS which has same frequency.
If you are super busy and can not have time, could you just lecture me where should I see the program?

Status: NeedInfo

[Dan Young]

I there a way to predict which runway is more likely to work?

[Hai Zhou]

Is this still being worked on? Also the link to the patch is broken. Is there any way for the patch to be included in the next release?

[legoboyvdlp]

Continued at https://sourceforge.net/p/flightgear/codetickets/2061/ and https://sourceforge.net/p/flightgear/codetickets/1983/