Why did an iPad software failure cause a return to the gate? I was amazed to read this which implies that a software failure on iPads caused departing flights to return to the gate.
I used to be an avionics engineer up until a point before the current generation of consumer electronics and now develop &quot;field&quot; apps for phones and tablets.  I know two things to be true.


Consumer phones and tablets of all persuasions used in field applications have nowhere near the reliability of certified avionics.  I own an iPad, amongst many
other devices, and it does not get close to six nines reliability (as do
none of my other consumer devices).  In particular, since the latest iPad updates over the last year or two, it's been quite buggy.

The hardware is not designed and built to the standards required for avionics and, without appropriate hardware, the
software cannot be to aviation standards either.



I know that these devices have been certified for use and I know why and what they are used for but I thought they were only convenience devices.  It seems that they have become part of the safety chain.
Are they MEL items?  Does anyone know what's really going on here?
iPads are used so the flight charts and manuals are electronic instead of the old phonebook that had to be printed and distributed every few months.

This means that without it the pilot has no up-to-date copy of the flight chart of the airport where he is trying to land which is a safety issue.