I've now had 2 concerned customers with drones that didn't fly back after a signal loss(since November last year), one was found the other is currently being searched for.  This is just a friendly reminder that if you are going to fly longer distances or over obstacles you really should be in GPS mode with good satellite coverage.  Failsafe does not fly the drone back with low satellite coverage, it lands.  To make things worse it will be landing and drifting because its in ATTI mode.

I haven't tested this scenario for several months.  Can anyone post recent experiences with failsafe in ATTI or just low sat coverage?

It seems like there is almost an infinite number of possibilities depending on how the user has their settings!

Certainly you are correct that ATTI is bad news if the quad is not close to you. Most newer models are set so that they RTF on low battery.

Whatever the situation, the odds of loss are FAR greater when not flying in LOS.

I had my plain Phantom (same NAZA flight controller) do the auto landing (no RTH, just land where it was) when it was at a distance. I think this depends on the calculations of the controller as to whether it has enough juice to make it home.

Failsafe is, IMHO, a poor way to describe this function. It should be more "pray and hope - and there is some possibility the quad will return". Even if it's 95% reliable, that means many quads will be lost each day.

My question is, why would the operator not switch into GPS and/or IOC (and just pull back on the right stick) at the instance of losing signal, I did it a couple of times tonight, flying WTF out there, I get my first indication I have lost signal, I switch to IOC/HomeLock and start to bring the Phantom back until I see I can regain control with good signal...
That said, I have not tested Failsafe in ATTI so maybe I missed the mark here and need to try it to see what happens and maybe the characteristic of Failsafe/RTH are as different in ATTI  mode as they are if you initiate an S2 down to Failsafe and have no control of the Phantom on the landing.,.
I will also add that you should know your surroundings well enough to know you have your RTH Height set for the area and as for satellites..well..they are where they are and if they were just at the minimum number of Sat's on take off it was probably not a good idea to venture out to long distances into the wild without an exit strategy.

Northofthe49th Posted at 2015-3-25 12:18
My question is, why would the operator not switch into GPS and/or IOC (and just pull back on the rig ...

They are different, there is no RTH with low satellite coverage (the exact number I'm not sure).  A scenario I experienced was flying with a low satellite count in GPS.  If for some reason you drop below 6 you are in ATTI and if you then lose your connection you are in trouble.
There is a very subtle difference in the manual:

Ready to Fly (non-GPS) - Automatic landing
Ready to Fly - Automatic go home and land

You are only in ATTI if you have S1 set to the middle position. If S1 is in the top position, you are in GPS mode -- or, non-GPS mode if you have less than 6 satellites.

Maybe I've just been lucky, but I've never seen less than 8, and generally 11-12 sats during my dozen or so flights thus far.

Solar flares knock them out? I guess it's possible, but given a clear view of the sky (which we generally have of course) I find it hard to believe it will lose all of them (or be down to 6 even).

After all, the GPS receivers/map apps in our phones work pretty much all the time, even in downtown San Francsico with its steel high rises and so on. The technology is pretty similar after all.

Having said that, given the 'paranoia' here, I did just install a Trackimo on mine, just in case.......

Cheers,
Ian

bradreid20@gmai Posted at 2015-3-25 12:31
They are different, there is no RTH with low satellite coverage (the exact number I'm not sure).  A ...

O.k,
I did not take low meaning as in below 6 Sat's locked and that is what it is, anything blow six and you will land in the sticks!

i have been getting 10 to 14 satelites lately.  don't have a low satelite problem here in socal.  The RTH feature went off this weekend and performed as required.

Northofthe49th Posted at 2015-3-25 22:54
O.k,
I did not take low meaning as in below 6 Sat's locked and that is what it is, anything blow s ...

yep below 6 sats for more than 20 seconds and failsafe = autoland and once autoland is initiated it will not abort it even if 6+ sats are locked again thereafter.