A320 - Left pack only on ground.
 

Why do some operators only run the left a/c pack on the A320 when on the ground?

Fuel economy is the reason, though my airline tries to alternate the pack usage.

Some prefer left pack as there is less chance for the loaders to put debris down the right...

Talk about overthinking it ��

We alternate it, left pack on on the taxi out, off on the taxi in.
We do it this way due to single engine taxi, which we are only allowed to do after landing.

Couldn't agree more check airman... Just heard several people doing it that way over the years and back in the day when the 'old 732 APU could only drive one pack we used to select the left for just that reason - which was stated in the manual of the time...

In my company left pack off for taxi out, right pack off for taxi in. On a personal account i tend to leave right pack off for the whole duration of the turnaround to comfort the loading staff. Both packs off for the pilot monitoring of the upcoming flight to be able to do his/hers walkaround with as little hearing loss as possible. Just my 2 cents...

Switching one pack off makes the other one spin just as noisy as two. Hardly any gain.
We used to do that, plus packs off take off, till we got many problems with the packs.
Now we leave them on all the time, no issues any more.