Originally Posted by
A and C
If you have an eQRH ( and some are very good ) then you need a paper back up to cover the situation of electrical problems disabling the eQRH or smoke in the cockpit that reduces visibility.
I know both situations are unlikely but Sod’s law says it will happen to someone some time.
Not true in all countries. Many allow dual iPad with the third iPad as a backup.
Airbus don’t provide a paper QRH and haven’t for 2 years.
And the EFBs have to be in an approved mount.