I understood it was illegal to depend on electronic equipment in the air?
A few airlines have switched over to digital maps for airports, since they offer some substantial advantages (less weight, more up to date, etc).
If you want to have a look at one of these apps, its on the public app store (https://itunes.apple.com/de/app/lido-iroutemanual-aeronautic...) - though I could not find a source that AA is using the LH Systems app (and if it was the source of the problem, I guess there would be several more stories about it.
edit: Source: did some work for LH Systems, but not affiliated with them.