First flyaway experience, hopefully the last

[xfreedommasterx]

Obvious, I know, but haven't seen it mentioned here (unless I missed it)... Have you checked your GPS plug for a tight fit? Some say it is thought to have intermittent issues with connectivity because of the crappy plug and receptacle hardware that doesn't mate too well. That may explain the random behavior. I modified mine to get a snug fit because it seemed to just pop out with no resistance at all when I took off the upper shell.

Nice work to save your bird. You're right on the money with getting prepared for flying without GPS. It's just a matter of time for all of us to lose a GPS lock for one reason or another.

I hadn't considered that. I'll give it a look over tonight when I have time to take a closer look. It'd be nice if the issue was that easy to fix and diagnose. If it was a simple fix like a loose plug I could fly easier knowing there isn't a phantom in my phantom waiting to flyaway.

 

[MapMaker53]

I know one theory is the loose GPS plug (and I myself have done the snug fix for that), but what shoots down the loose GPS plug theory is the total loss of stick control. Lose GPS and you automatically drop down into ATTI -- but you always retain stick response. I think loosing stick control while in GPS mode but being able to regain stick control by flipping to ATTI mode to me suggests a firmware gremlin that raises it's ugly head every now and then. Could be a Phantom glitch, could be an RC glitch.

 

[justin00]

Very odd.... I had a similar situation sges ago....

Few mins into second flight of the day (first flight as in using up battery #1) and all of a sudden lost all RC control/inputs. Just before I lost control I was just going forward into the wind then I purposefully stopped and let it hover. When I wanted it to resume fkying around and moved controls nothing happened. Sticks had no affect. Couple of seconds later it started goibg forward into the wind in a straight line, not all crazy like yours was doing. The entire time FPV was working and app reported a suitable amoubt of satts. What makes mine diff to yours was I lost all RC. S1, S2, sticks etc etc all had no affect and changing didnt do anything. After about 10 seconds I get a message popping up saying control signsl lost and it flew back home. If it hadnt been for the automatic fly back home if no RC functiomality it woukd of literally flew away.
Once back within a few feet of me I hand caught it and had to press bsttery button to turn off motors. wierd thing was it was not far away at all...maybe 100ft horizontal and 50 ft vertical, well within range. Turning off RC had no affect and I only regained use of the RC was by rebooting the phantom. Also happened at a spot I had flown at 50 times before and probably 100 times after and only ever once hsve I had that problem... both batteries been charged over 160 times each so ive done fair bit of flying..
Anyways still have no idea how/why..... if it was a firnware or hardware issue I should if had problem again i would of thought, but nope no idea.... my only thought was extrene interferrance but instead of regaining control the interferance pissed off the RC TX or RX and only reboot ciuld resolve. Like I said though been in same spot 100+ times and only happened once. If it was interferance it shiukd be a constant issue for me, in that area.

Watchibg your vid is scary!! You were seconds away from crashing into the bridge!!!

 

[ianwood]

This is all compass. Nothing to do with GPS. When it leans left and right and circles around, that's the compass flipping out. TBE. By flipping to ATTI, the compass wasn't being used to navigate which allowed you to regain some control.

 

[N017RW]

I know one theory is the loose GPS plug (and I myself have done the snug fix for that), but what shoots down the loose GPS plug theory is the total loss of stick control. Lose GPS and you automatically drop down into ATTI -- but you always retain stick response. I think loosing stick control while in GPS mode but being able to regain stick control by flipping to ATTI mode to me suggests a firmware gremlin that raises it's ugly head every now and then. Could be a Phantom glitch, could be an RC glitch.

I know you mean to help, but of what value is the last two sentences???

Why not just say you don't know rather than foster or promote superstitions?

 

[SnoozeDoggyDog]

I calibrated the compass far away from the bridge and off the concrete path that leads to it. As far as the solar k level, from what I saw after looking it up, it was at normal levels. As far are electrical interference goes, I can't rule that out entirely either because the bridge does have lights on it but I'd think that flying in a city would cause more issues than out on a remote bridge. This bridge is miles out of any town and I had to hike 1/2 just to get to it. I didn't see any nearby transformers, cell towers or high tension lines that would give me reason to pause.

Calibrated on a Concrete path? Reinforced concrete has a steel frame within it. Just a thought .....

 

[MapMaker53]

I know you mean to help, but of what value is the last two sentences??? Why not just say you don't know rather than foster or promote superstitions?

Well, that's what a theory is and they are put forth all of the time in forums in an attempt to brainstorm. I still stand by my thinking that a glitch in the DJI firmware is to blame for non-pilot error P2V+v3 crashes. Here's a recently posted screen capture video in this forum showing such a crash. Unless you can provide another reason why the Phantom's speed being reported on the screen at 10 seconds into the video suddenly jumps from 0.7 m.p.h. to around 2000 m.p.h., I'd say the firmware is relaying commands based on sudden misinformation at times.

 

[PaganLinuxGeek]

This is the original poster of this video. It might be significant to note that the rest of the flight went smooth and I was preparing to shutdown and leave when she suddenly dove hard to port so fast that the phantom was 90 degrees off its axis. I mean to say that the propellers were vertical. My fingers were OFF the STICKS and she was in GPS mode. There we no indications of interference, IMU and compass calibration was done, firmware up to date on camera, transmitter, and phantom. Preflight checks are always done.

 

[Prowler]

These problems seem to be common. I have had these same type of issues myself. Mine seems to fly fine for many many hours then one day poof it does some random BS like u guys have posted about. I never see any symptom's that it going to behave bad so I just always gotta keep my eye on it. So far I've gotten it back, but one day it just took off and would not respond to any controls, but I have gps tracker so I find it 1/2 mile away high in tree.

 

[xfreedommasterx]

I have considered getting a GPS tracker but so far haven't seen a need to get one until this recent flyaway experience. I'm not sure what might have caused this particular flyaway but I do seem to be leaning towards it being a compass issue. I'm not sure if it was a bad calibration or a malfunction, I'd like to think that it wasn't a firmware issue cause if it is, it could go at anytime no matter what precautions I take before take off.

 

[Prowler]

it could go at anytime no matter what precautions I take before take off.

This is something everyone needs to remember while flying. That and get a tracker. One second mine was flying good no problems the next second no GPS signal went to ATTI mode. Was able to bring in via ATTI mode. Set it down, restarted it, took off this time it stayed in GPS mode but acted like it was in ATTI mode or worse, I was driving like I was drunk. So I came to a crashing landing only breaking two prop guards.

 

[yorlik]

This is all compass. Nothing to do with GPS. When it leans left and right and circles around, that's the compass flipping out. TBE. By flipping to ATTI, the compass wasn't being used to navigate which allowed you to regain some control.

Is this correct?

It has been my understanding that in ATTI GPS is not used, but compass still is?

I THINK I have verified this by switching to ATTI and also CL and verifying compass original CL position is still valid.....

 

[ianwood]

CL uses the compass. Normal ATTI does not.

 

[yorlik]

so... if I am in ATTI then CL does not work?

 

[PaganLinuxGeek]

It is my understanding that the compass is used in GPS mode. Also used in Course Lock mode.
Course lock can be used in GPS or ATTI modes. Again this is my understanding.

 

[yorlik]

You had me very concerned since I have always believed one of my failsafes to get an errant p2v+ back is ATTI mode and course lock. This is why I always take off with my quad pointing north - that way I know direction if I have to go to ATTI and bring it home by compass only...

So I just went out and flew: I can say with 100% certainty that your statement is wrong: CL works as advertised in ATTI mode.

Therefore, saying switching to ATTI disables the compass must be wrong, and by continuing the logic, saying it was a compass error that caused this OP issue, MAY also be incorrect since switching to ATTI does not appear to disable the compass input to the controller inside the quad... Am I wrong pushing the logic this far? Maybe the compass IS disabled for all ATTI use EXCEPT if S2 is put in CL position it is turned back on?

Jeesh, why can't DJI give clear descriptions??

 

[yorlik]

Obviously I may be wrong. I once heard it said that even in ATTI, RTH works if GPS was left locked on enough sats, and a home position was previously set.... Unless someone has tested this one to verify it, guess that will be another test to do! Can't today as I can only get 4 sats under the trees here and no time to go somewhere else right now... I would love it if someone can verify or disprove this one.... thanks.

 

[jumanoc]

Open shell and check GPS connector is secured onto board connector. There is a known issue because that GPS cable looses connection due vibration on flight. I uses hot glue after having a similar scenario.

 

[PaganLinuxGeek]

It would seem that if the GPS is not functioning then phantom would not know it's current position and therefore couldn't navigate to it's home point...

 

[MapMaker53]

Easiest fix for that is to just stick a small piece of Velcro looping onto the side of the GPS plug to make it a snug connection. It won't pop off, but you can disconnect whenever you open the shell.

http://www.phantompilots.com/attachments/20141221_200619-jpg.12895/

But I doubt this was your problem in both of your instances. It would have just dropped into ATTI Mode, not flipped 90 degrees and crashed.