Glideslope callout on take off

[Christopher Low 5,352]

I am sure that I have mentioned this before, but I am not able to find the original post. In short....I experienced a "glideslope" callout during take off this morning in the 747-400 F at EGCC Manchester (and I think that the same thing happened with the 747-400 BCF a few days ago....at the same airport). As far as I can recall, I have only ever heard this happen when taking off at EGCC Manchester, and only in the 747. Does anyone have any suggestions?

[berts 97]

I've not come across this problem using UK2000's EGCC scenery with the PMDG B744. 

There are so many possible variables that you will need to provide a lot more information if you want someone to try and reproduce this and maybe troubleshoot it for you.  For example: what runway were you using? Was it the first take-off and flight of the day? What ILS FREQ and Radial did you have tuned in the FMS CDUs and were they auto-tuned or manually inserted?  Were you flying manually or with the autopilot engaged and if so what modes were you using?  What was your height AGL when the callout occured and were you still climbing? What aircraft configuration and performance settings were you using? Were all of the PMDG failure modes switched off?  These are just a few of the questions I can think of where your answers would be helpful.

Bertie Goddard

Edited July 16, 2018 by berts
amended

[Christopher Low 5,352]

Bertie,

I will try to answer as many of your questions as I can!

 

Take off on runway 23L

It was my first take off and flight of that session. I always restart the simulator for new flights.

It was a circuit of the airport, and the runway 23R ILS frequency was auto selected when I entered the flightplan and other details in the FMC.

I am not absolutely sure what you mean with respect to the "radial", but 230 degrees was the heading selected on the MCP.

I was still flying manually, as the aircraft had only just left the ground. Height was probably less than 200 feet.

I am not quite sure what you need with respect to "aircraft configuration and performance" settings, so can you be a bit more specific?

As far as I am aware, failures are disabled (I will need to check to be certain, although I have not suffered similar problems elsewhere).

 

 

[downscc 1,327]

Christopher, can you reproduce this event?  My very poor memory recalls a false glideslope warning topic some time ago, I'm not even sure if it was the 747 or the 777.  I'm not sure it was resolved.  It would be sweet if you could reliably recreate the problem and then communicate that such that others could recreate it.  Either we could find an error in procedure (unlikely in my opinion) or isolate a bug.

[Christopher Low 5,352]

I will recreate the same flight with the same startup parameters, Dan. I will try to get as much information as possible.

[Johannvr 3]

Christopher I suspect your issue is the circuit flight at EGCC you did. Rwy23R and rwy05L have the same ILS frequency 109.50. Taking off on rwy23R and ILS freq. 109.50 auto tuned for your approach on rwy23R will take you "into" the glideslope of rwy05L ILS at the same frequency.

[Mike777 163]

Hi Christopher,

Even though you had just started up FS, is it possible you used a saved flight where the FDs had not been cycled off and on, and you were still in Approach mode from a previous flight?  I once had a 777 try to follow the LOC and GS after takeoff for this reason, even with a new flight plan.

Mike

 

[Christopher Low 5,352]

I do not save previous flights. I just load from a basic saved scenario before the Flight Directors have even been switched on.

[Mike777 163]

5 hours ago, Christopher Low said:

I do not save previous flights. I just load from a basic saved scenario before the Flight Directors have even been switched on.

Hi Chris,

Have you tried starting the same flight that is causing problems from a completely new setup?  Sometimes an  existing panel state can get corrupted.

Mike

 

[Christopher Low 5,352]

A good suggestion, although I am not sure why it would only happen at EGCC Manchester....

[Christopher Low 5,352]

OK, I have just replayed the start of that test flight, and the "glideslope" callout was again audible just after take off. I have attached five screenshots to my next post, showing the FMA and ND screens (and MCP) at various times between holding for departure and initial climb out....

1. Hold Short at Runway 23L, EGCC Manchester

2. Runway 23L threshold

3. Accelerating down the runway

4. Just after the "glideslope" callout (about 100 feet off the ground)

5. Autopilot now engaged, and around 600 feet off the ground)

 

I am not sure what other information you guys need, but feel free to ask!

Edited July 22, 2018 by Christopher Low

[downscc 1,327]

Christopher, those links take me to a screen where I could download the images rather than view them.  I'm not a big fan of downloading files.  Thanks.

[Christopher Low 5,352]

 

 

 

 

Edited July 22, 2018 by Christopher Low

[Johannvr 3]

Christopher, have you tried departing without programming an approach on rwy 23R? Confirming on FMC NAV RAD that ILS freq. 109.50 not tuned. I noticed on the PFD the ILS Ident is IMM, which is for rwy05L. Rwy23R ILS Ident is INN. This might cause the system to sense below glideslope (on rwy05L), as you can see on the PFD in your 4th picture, hence the "glideslope" callout. It seems strange that in your sim, ILS for rwy05L (IMM) is displayed on the PFD while ILS rwy23R (INN) is selected for approach.

 

 

[downscc 1,327]

I keyed on the same thing as Johann.  I see INN during takeoff then in #4 it become IMM.  Not sure what you got programmed there.  INN being ILS23R and IMM being ILS05L as said by Johann.  You  are taking off 23L.  Please explain.

I've reviewed the GPWS in the FCOM and cannot find that the glideslope aural is ever inhibited, so the proper step when it is a false callout is to use the G/S INHIBIT SW.