Xiaomi Redmi Note 3 keeps restarting as mad when charging (until airplane mode) My Xiaomi Redmi Note 3 keeps restarting as mad when I charge it, but when the airplane mode is turned on, it tends to behave.

I suppose it's not a hardware issue, but something more complicated. I suppose the device tries to upgrade software when charging and it fails which causes software (it kept asking me about manual updates, each time I tried to update, it failed). My current MIU version is 6.1.14 beta, I have no idea how outdated it is. That misbehaviour makes it impossible to charge phone, because each restart eats more power than it was charged in the meantime, until airplane mode, which renders phone useless when charging. 

Is there anything that can be done to save the phone, or it simply belongs to trash bin? 

The phone is relatively new, it was used by about half a year.
Your phone is in beta rom.Try to flash latest global stable rom by edl mode,maybe this may solve the issue.