If I exit or reboot the iPad, plates I had previously downloaded are lost, and I have to download again.

That's actuallyvery important tome, too. When I plan the flight on the ground I have all the required plates accessible. But if somerhing happens and I have to close SD or reboot the iPad I loose them. When this happens in the air I can't get them back. It is also costly to download them again with all the roaming charges on mobile networks.

-- Chris.

I just found an older thread which discusses this issue (http://www.skydemon.aero/forums/Topic6878.aspx?Update=1#bm6983). Apparently all plates and notams are already cached.

-- Chris.

The statements made at the beginning of this thread are not correct. Once a plate is downloaded it is stored forever, or until it is replaced by a newer version.