Yesterday I waved goodbye to my much-loved 5inch. Was fitted with a MAMBA MK4 F722 MINI the MAMBA M8PLUS GPS unit and a HGLRC Forward 5.8GHz 400mW VTX.
I usually test fly in an open area next to our compound and have a big cell tower about 100m or less from where I usually stand and operate the drones. This time I flew in the opposite direction as there is a larger open area because I wanted to test the RTH function as I started considering medium range flights with the 5 inch.
At first everything was going well, then I started noticing the home direction arrow on the monitor didn’t point in the right direction anymore. I flipped the switch into horizon mode, and it started to act very strange, didn’t respond to the way it should to the stick inputs. The drone was less than 60m from me (making it 160 odd meters from the tower) and started drifting away, I thought okay if anything this is the time to test the RTH for what it’s worth. It started gaining altitude and I got encouraged until it turned in the complete wrong direction and started flying away. It changed direction again and started flying away sideways. The next moment I lost visual, and it was already too far to have LOS, my son was spotting for me. I cancelled the TRH and tried to gain more altitude in the hope the VTX will restore but all in vain, it left me for good. When I reviewed the recording, I noticed it also gave complete incorrect distance from home readings (hindsight yeah).

Here is the question though, is it possible that the tower caused all this interference? As a norm we only fly 3” in this area without GPS so my only logic explanation is that the GPS, FC and VTX all got influenced by strong signals from the tower. Any suggestions as to my suspicion?

your suspicions may be far from the truth sir.

i believe the cell tower had nothing to do with the erroneous RTH behavior. of course we are assuming you have previously conducted several successful flight tests that your gps rescue is working properly and reliably.

you already lost battle the moment you noticed home point did not indicate the correct direction. after establishing 3D fix that home arrow must point to (at least) the general direction of home a few meters away after quad gets airborne. the next worse thing you did was attempt RTH without this prerequisite. in doing so the quad will follow whatever direction of home regardless if it’s correct or not.

it also seems you were not in full control of the quad at any point during the time you suspected something was already amiss. always keep in mind that it is only you, the pilot who is ALWAYS flying the quad. in lieu of any external forces like cell tower, RF interference, or failsafe event, it is your primary responsibility to relinquish full control of the quad immediately if anything doesn’t seem right.

OTOH, if it were indeed the cell tower that (may have) caused your flyaway, the interference should have triggered gps rescue (if your failsafe was set up this way) then your quad would also follow the incorrect home direction as it did when you triggered gps rescue manually. so in essence it’s not the cell tower to blame. it’s your dysfunctional gps rescue.

flyaway events involving perfectly flying quads are always unfortunate. in majority of the cases the pilot has already become a helpless passenger when he/she relies on the autonomous features (like gps rescue) to save the day. more sadly is when said features fail when you need it the most.

HTH, sorry for your loss.

Thanks for the response, I do agree with you on the first indicator, the time I noticed the home location indicator issue that chain of failures that happens so quick started, last resort was to cut the motos, but I wanted to retrieve the quad rather than blindly crash it, which eventually did happen, but I missed that window of opportunity. I can only hope and pray it was into a wall or open area somewhere and not a person.