ILS help please

[akontra 0]

Hi there,

I wasn't sure where to post this, so thought I would start here.  I am using FSX SE and PMDG 737NGX. I used to be able to do ILS landings quite routinely, however, lately the following problem has developed... Both localiser and glide slope are alive, and I am on final approach. Suddenly the airplane goes off course, seemingly in a random direction. This does not happen every time, but probably in about half the instances. I don't know whether this is some kind of a known bug or an operator error on my behalf. I would be extraordinarily grateful if someone would suggest either how to fix the problem (if a known technical bug) or what I may be doing wrong procedurally. If I've posted in the wrong forum, please suggest where its best to re-post. Thanking you all in advance.

[vadriver 247]

perhaps try a search / post on

https://forum.pmdg.com/forum/main-forum/pmdg-737-ngx &/or https://www.avsim.com/forums/forum/432-pmdg-737ngx-737ngxu/

but a few questions ......

• does app mode engage
• same airport / same ils or various
• have you checked the frequency of your charts against those of the sim
• have you set the localiser course on the selector

 

 

[akontra 0]

Thank you vadriver fro your fast response. I will have a search around these forums. In answer to your specific question:-

• does app mode engage - yes, and so does the loc/app mode
• same airport / same ils or various - various airports, but intermittently successful or unsuccessful
• have you checked the frequency of your charts against those of the sim - no, but considering that the app approach is engaged and both the localiser and glide slope are alive, I would say that this is highly unlikely to be an issue. I will double check though...
• have you set the localiser course on the selector - yes

[vadriver 247]

2 hours ago, akontra said:

and so does the loc/app mode

that's the vor/loc mode ....... where your laterals would be fine but no capture of the vertical glideslope.

but otherwise, as you wrote the ils is initially alive & then captured (app engaged)

after which, do you set the missed approach altitude > 300' below that altitude .... can be lower than the G/S capture altitude (& this can upset the A/P and / or modes).

Edited September 29, 2020 by vadriver

[akontra 0]

Hi vadriver - thank you again... The answer to your last question in "no". I wasn't aware of this requirement and have never done it. I will need to look up this procedure in more detail and comply. Hopefully this is the culprit. Thank you and cheers, 

[vadriver 247]

14 hours ago, akontra said:

Hopefully this is the culprit.

well kinda ...... if you don't do it, you'll only mess up an automated go-around (missed approach) not the approach.

if you do it "too high", then it will mess up the approach ....... & more so with a VNAV / V/S procedure.

the only remaining idea i can offer is make sure you set ils frequency / course selector & cmd all on at least the one and same side.

[akontra 0]

Thank you once again, vadriver. I have refreshed myself on the procedures and have had several ILS landings successfully. No issues. I think its now fairly obvious that it wasn't a technical problem but an operator error. Thank you for setting me straight 😉

[vadriver 247]

5 minutes ago, akontra said:

Thank you for setting me straight

& your ILS's ..... enjoy