3 BARS on the MIC Selector on the ACP.
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3 BARS on the MIC Selector on the ACP.
What is the significance of the 3 BARS which illuminate, when a transmitter is selected for transmission on the ACP. It's vertical on the 737 and horizontal on the A320.
I'd hazard a guess that there's no significance to it being 3 bars, regardless of orientation. You simply need to be able to look down at the panel and see something which indicates which button is selected..TBH it could just as easily be dots or stars, whatever......
FWIW on some Boeings you simply get a backlit illuminated "MIC" where appropriate.
FWIW on some Boeings you simply get a backlit illuminated "MIC" where appropriate.
Last edited by wiggy; 2nd Jul 2017 at 13:22.
RE 3 Bars - I expect that is "functional design" - make the MIC/TRANSMIT selection buttons quickly distinguishable from all the other pedestal lights/buttons at night.
Alternatively - could be simply 3 LEDS for redundancy, in case one burns out. But the fact that the pattern (3 bars, regardless of orientation) is common across B and A makes the first idea more likely. Embraer uses one bar - but still a bar (EMB reception controls have round indicator lights).
Alternatively - could be simply 3 LEDS for redundancy, in case one burns out. But the fact that the pattern (3 bars, regardless of orientation) is common across B and A makes the first idea more likely. Embraer uses one bar - but still a bar (EMB reception controls have round indicator lights).
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And Boeing and Airbus would always be opposite. On the Airbus overhead panel up is on and down is off. Boeing is round the other way!
PS The threebars in my Boeing are horizontal!
