On several occasions I have down loaded the charts in the AIP. When planning the trip they are in the memory. After shutting down the iPad and restarting for the trip the AIP charts have disappeared. Have I some incorrect settings?

Hello,
I had the same problem happen to me today (Android 4.4.4)
I tried a few things to reproduce the problem.
The problem only occurs on first tries : if the plate is not shown when off line, and then it appears while being online (with a green background showing it is downloaded) it will thereafter always appear except if I clear the cache (Settings - Application.....)
But the problem completely disappeared after I updated the AIP.
May be there is some internal check for out of date plates.
Hope this helps.
Pascal