This problem appeared a week or so ago for me, using version 3.4.1 on a Samsung Galaxy S2. As others have commented, the chart comes back if I select on of the tabs along the side in flying mode.

Just purchased skydemon and installed latest version 3.4.1 on my android phone running jelly bean 4.4.2. I came across the same issue with the charts randomly disappearing, clicked on Flight tab and the chart usually appears again, but not always. I came across this post and downgraded to 3.3.2 and all is working perfectly now. 

It would be good to see this fixed so we can install the latest version:-)

Unfortunately this is one of those problems we just cannot see on any of our test devices in the office. I reviewed the main code changes post 3.3.2 build though and identified a couple of potential suspects. I have just published a new beta build. Please test it and let me know if it helps at all.

I Installed the beta on my droid phone, and initial findings would seem that all mapping is working correctly now.
Cheers,
KevW.

Thanks Kev. Can anybody else confirm too, please?

I had this problem yesterday for the first time on my Samsung Tab 7.
I have installed the beta version this morning and from testing in the garden it now seems OK.
[Flying home from the LAA rally on Friday mapping was all OK but I couldn't get a route leg I was joining to be displayed. I tried direct to a point but got no track display on map - the nav data to the point was all correct.]

I had somethlingl like this in Warsaw. Ipad 2 wth skydemon 3.4.1.15. All perfectly OK in the terminal, but after laborious departure procedures etc and after starting the engine, no maps! With no time to investigate further, switched to backup ipad and used that. After landing it worked normally. Screencap shows attempt to reload maps, but obviously to 3G or wifi in the aircraft.

I had the same problem with map disappearing - using anyone of the toggles on the right and map reappears. Had 3.4.1.29177 installed on Android 4.2.2 However problem fixed by installing your beta 11 sep 15

Had the same problem for a few weeks on a Samsung Galaxy 2 running Android 4.0.4. Seemed to occur when activating "Go Flying" mode (just when you don't want it!). Have downloaded Beta and seems to be working OK