Audio Control Panel Mystery.

[forget]

I asked this some time ago but never did get an answer I understood. Audio Control Panels below were fitted (at least) to BA 757s for MLS trials. Question is - How do you select/de-select Marker Audio?

It’s an Avtech 5051-1-5. I’m told by the manufacturer (who thinks!) that ………… you can turn off the ILS/MLS received audio so that only the MB will be present. This is accomplished by repeatedly pushing the ILS/MLS Vol Control switch until the ILS/MLS LEDs (right, center, left) are off.

This all sounds very iffy. For a start, there’s no MB Placard. Anyone out there with a MB Test Set and an ex MLS trials aircraft handy. Forever grateful! :)


http://i21.photobucket.com/albums/b270/cumpas/7572.jpg

[forget]

Answering my own question here. Info from manufacturer. The Marker Audio is ON whenever any of the three ILS/MLS channels are selected. Marker Volume is not adjustable but is pre-set external to the Audio Selector Panel.

So, to hear the Marker Audio you have to - Select any ILS/MLS channel, light on, and turn down the volume to get rid of any ILS Ident that may be there. :bored:

This has to be the worst/clumsiest audio design of all time :confused:!