I don’t know how it works IRL but I have a doubt regarding the Nav & Logo light switch:
It has 3 positions: OFF / 1 / 2.
I would think that position 1 is only nav lights and position 2 nav lights + logo
But whatever the position 1 or 2, logo is always on. Should not it be lighted up only if 2 is selected ?
The 1 and 2 refer to nav and logo systems 1 and 2. There are redundant systems so if one fails you can switch over to the other. Logo will be on in either position (until in the air and flaps retracted). You can also see similar behavior in the Fenix.
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Excellent, thank you !
When I was first learning the Airbuses I had the exact same question, so I’m glad it could come full circle 
for bulb life management, airlines will alternate between system 1 & 2…
like for example outbound flights will use 1, with return flights using 2…
or odd numbered day use 1 and even days use 2 etc. depends on SOP
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