A320 navigation lights, how do you use them, do you alternate between sys 1 and sys 2
 

Some people use sys 1 for odds days and sys 2 for pairs.
Others depending on the flight number.
What's your company policy?
How do you save the "bulbs life"? If any....

#1 if the Captain is flying, #2 if the F/O is flying. Goes nicely with transponder selection.

We also use #1 for capt PF, #2 for f/o PF

great to see others get to grips with the non-essentials

Give me strength. Is this genuinely written down in some airlines? I thought we had prescriptivie SOPs but bloody hell...

I only crash on Wednesdays!

But only if Nav Lights are #2....

On a Daily check we switch them anyway.

Nav Lights on 1. If any seem to be INOP, switch to 2.

Only 1, with 2 as back up.
Related question:

Do you use your NAV lights during the day?
We do in my company although our manual doesn't tell us to ('as required').

SOP at our company is NAV lights left on all the time 7-24, 365.

Airbus NAV lights stay in position two, position one if position two inoperative.

It does get ridiculous at some point, doesn't it? My last airline's SOP said something like "when 2 systems are available, use 1/2 if the CA/FO is flying".

It made sense for the AP and transponder. Most people would just leave the nav light in whatever position it was in when we walked into the cockpit.

Nav Lights are ancient technology invented for use on boats. They found their way into aviation when the fasted thing in the sky maybe did 200kts.
They are really a redundant piece of equipment on modern aircraft!

DJP, with all the fools who stooge around the London TMA at night without landing lights I'd say nav lights are still very useful indeed.
They also highlight where wingtips are at night and in low vis. I don't think they're redundant at all.

Don't forget taxying around a dark (or foggy) airport, NAV lights are sometimes all you see!
So not outdated at all. Some operators even switch on the wing scan light just to be more conspicuous.

Using one system all of the time and the other for back up is one way of helping to ensure at least one system is hopefully always fully serviceable. The same logic can be applied to other redundant systems where only one is in 'use' at any one time.

If both systems are used equally, on alternate days for instance, you are more likely to have failures around the same time as the associated components have had the same amount of use. Obviously, it is still rare to have dual failures and there are other factors involved other than hours of use but it made sense to me when a colleague explained it to me! That said as an aircraft accumulates time, more and more high failure rate items are being replaced introducing splits in individual operation times regardless... ah... do whatever the SOP says :}

What's the point? Use the one that isn't inop. MEL'd logo lights will help you decide which one to use

Switch it to one, i'm too lazy to switch it to two, except if one is inop. Apparently preety much all of our pilots domit that way, but there is no SOP for that.

And why is it that people flick the switch when reading the EXT LT from the Parking C/L?

:)

Multi-fingered switch flickers are among the scariest people in aviation imo.

Baad habit, baad CRM - flicking switches. Switches should be positively moved - just gives the brain as well as the other pilot a chance to verify that what you are switching is what you (both) intended to switch.
It's not like a piano where a bum note just isn't important...

The airbus only has extendible landing lights, with the attendant vibration and fuel penalties - unlike the Boeing with it's set of lights in the wing root fairing. ... So they are only fools for flying an airbus, instead of a Boeing. ;)