I am uncertain about the activation of a failsafe procedure if flying in Phantom Mode. In ready to fly - GPS mode in the event of a wifi failure or transmitter being turned off, the phantom returns home. However, if, whilst flying, I lose some satellites ( below 6 ) I presume I am now in ATTI mode. if I then lose wifi for whatever reason will failsafe activate in this situation?  

I believe there is no GPS input in ATTI and the manual states that in "ready to Fly - non GPS mode an automatic landing can be made but there will be no  drift compensation - fine. However, if it has lost GPS and thus position, how does it know where to return to? I assume it works on its recorded home position and the last known gps position and using the compass attempts a return from there - but if there is no GPS surely it cannot pinpoint the Home position before it commences descent.

Grateful if anypne can clarify 'muddled thinking'!

As you said, no GPS it will Auto-land where it is.
If there is any wind it will be blown in the wind direction while it reduces altitude to land.
Without GPS lock it will NOT come home.

OK great thanks, that clarifies that one. I did  wonder if it would return to near home by using Dead Reckoning and then auto land.
I appreciate your reply,
thks