Whats the GLS pushbutton on the A319/321 a/c for?

[Agni]

Its located on the RMP along with the stby nav aid tuning pushbuttons. The ones in our a/c are disabled, and this button is not displayed or talked about in any FCOM chapter that Ive checked.

[TheCosmicFrog]

It's not in the A320 then?

[Henry VIII]

Not present neither on our acft nor on our FCOM.
Present ILS and MLS.
It is NOT present on Airbus Reference Language Book either.
The only reference I found to GLS is here (http://www.aviationtoday.com/av/categories/commercial/12645.html).

[ROSUN]

GPS Landing system button?

www.embedded-computing.com/news/db/?10441

[Henry VIII]

GPS LS, but what is to be tuned on emergency on RMP ? LS course ?
Agni, what the RMP displays show after GLS activation ?

[Denti]

GLS approaches are identified by a "Frequency" and a normal identifier. However that "Frequency" is not a normal nav frequency so you have to be able to enter digits that are not normally used in nav frequencies. In our NGs we have to switch the nav mode of the nav radio to GLS and then enter the GLS-Frequency that way.

Nice example can be seen on the trial GLS in EDDW, for example on runway 09 (http://free.pages.at/denti/EDDW_GLS_09.pdf) right above the map picture (not to be used for actual navigation).

[Port Strobe]

Possibly thread drift (development? :}) here, but at the minima on the bottom of that plate, it states 650m RVR is required, or 1200m RVR with APL U/S. Is one correct to assume APL means autopilot? If so, I take it if being hand flown or the autopilot drops out, then the approach ban works in the manner we're accustomed to with required RVRs and continuation of the approach being dependent upon your position relative to the OM or equivalent position? Why is there such a restriction placed on the use of automatics when the flight director guidance on a GNSS approach is identical to that of the ILS which places no such restriction down to Cat I minima? (Or even Cat II/III if properly equipped come to think of it). If one were to lose the flight directors then the "raw data" could still be displayed between the ND and the FMC progress page for vertical and lateral deviation respectively on the platform I'm familiar with at least, although it would be a somewhat awkward scan granted. Any info much appreciated.

[Denti]

APL Approach Lighting (System). And yes, i know those EAG charts suck, just the only ones i have acces to at the moment.

[Port Strobe]

Which renders that last post somewhat useless :ok: Thanks, hope you don't have to use EAG perfromance as well :ugh:

[PT6A]

Is this some kind of digital system? Never heard of it before....

It sounds like the GLS numbers are a sort of channel on the freq, not really sure why they would want such a system... but would love to know more!

PT6

[Agni]

Well, I got to know from the Jeppessen abbreviations chapter that GLS is indeed GNSS Landing System, something that our airline doesnt use, hence it is deactivated.

Henry VIII: Since the pb is deactivated, the two windows on the RMP are blank when you press the GLS button.

Cosmic Frog: It could very well be on the A 320. Its just that our 319/321 are relatively a lot newer than the 320s, hence the extra/more uptodate features.