Volume Knobs for Marker Beacon Audio

[Frederf]

I am a bit confused about the audio knobs for ILS marker beacon audio. The ILS identification is controlled by the knob marked V/ILS which is normal but there are knobs:

 

TB/APP

TP MKR CME

 

The upcoming new manual says the second knob "sets the volume of the Table de Pannes (TP), marker (MKR?), and countermeasure system audio. But in practice the marker volume is controlled by the knob marked TB/APP.

 

What's controlled by the /APP part of the TB/APP that isn't covered under ILS or TCN or V/ or marker beacon?

[myHelljumper]

I think it's the other way around:

APP would be for the marker beacon, TB I don't know

MKR wouldn't be the short for "Marqueur" in french, IIRC on the PCN you have a button labelled MRQ to create mark points.

 

I would have to check the french manual to see if there is any more info on this and if my guesses are correct.

 

Will check this evening and come back to you :).