After the HMD loses tracking my view is filled with light blue, but it doesn't seem to want to start tracking again, no matter how much I wave it in front of a lighthouse.
It can be fixed by totally closing Prepar3d which turns off the HMD, and starting FlyInside again.
This can be reproduced by starting a flight, and then covering the hmd with a thick t-shirt...
Could FlyInside try and re-initialize tracking if it's lost? Or have a button for this?