I had some fun flying today (P3Adv), and pretty much flew it till RTH kicked on low battery. While flying back i took over quite a bit, then cancelled RTH (20% battery).
Close to the landing spot it went into autolanding mode, because of critically low battery - 10%, again expected and fine with me.  
As it was sort of too close to a tree, I started adjusting the position, and it felt like the forward/reverse were reversed, so the drone started to go (while still autolanding) over the water, rather than where I wanted it to go.
When I look at replay on DJI go, i can see me pushing the right stick forward and the drone going back! Then as i gain altitude, it recovers and behaves! (3 images attached)

Here's HD link:
http://healthydrones.com/main?share=XnYFpG

I have also noticed that while the red bliniking "battery low" is blinking, I cannot see if I am in GPS mode, or atti or other... not in the place I usually see "green GPS", and as I had my hands full, I did not clidk the button to get details...

Anyhow, some ideas would be appreciated.. This did NOT give me a warm fuzzy... even though I did not have an accident this time (no accident in EITHER meaning of the word ;) )
Could this be something in the 1.8.80 firmware perhaps?

I woudl love to hear of DJI's take on that too, but also of anyone else who experienced it or has a theory!

Thx!

Hi gtokarsk! I believe you got confused because the drone was facing you. In this case all the controls would be flipped (left is right , right is left)

DJI-Tim Posted at 2016-5-5 10:05
Hi gtokarsk! I believe you got confused because the drone was facing you. In this case all the contr ...

Absolutely.

When you make your next drone.

Can you make it in the shape of an arrow, so we can always see which way it's pointing.

malvern Posted at 2016-5-5 06:43
When you make your next drone.

Can you make it in the shape of an arrow, so we can always see which ...

Lol!!!!!!!

Am I missing something guys?  Phantom doesn't have a headless mode.  On the map it shows the orientation of the phantom, it shows him pushing forward on the stick, but the next screen clearly shows it has moved farther away from it's "front"?   That has nothing to do with his vision, it shows the phantoms orientation on the map and appears to be moving backward while he is pushing forward on the stick.  Unless I'm interpreting that incorrectly, he did indeed experience reverse controls for a few moments which could have been disastrous.

DJI-Tim Posted at 2016-5-5 02:05
Hi gtokarsk! I believe you got confused because the drone was facing you. In this case all the contr ...

Well, did you look at the attached screenshots? It confirms (or seems to) I was pushing the stick forward and the aircraft was clearly moving back. So I would disagree that is was simple confusion. I have flown RC aircraft for years.. so no, I does not seem that in this case I simply got confused, and the DJI app log confirms it...
I did recover, and I could get it working, it was just not a behavior I expected nor can explain.... So I would really appreciate if you can help me to dig into it, and again, for the sake of others, I chose to do this here.
Just imagine, if I was too close to a tree and moved towards vs away, esp. over water, that would MEGA-SUCK... (there was a posibility of issues as this was confined area and low battery, so I planned and made sure I was OVER the trees, not next to them and that saved me) so I am sure you can understand why I am really wanting to get to the bottom of this.... I am sure open to the posibility that I goofed up , but I really do not believe so....Log attached

GT

did you have home lock on?

kcmusa Posted at 2016-5-5 10:48
did you have home lock on?

That was going to be my next question.

No! Not on purpose, but it sure acted like I would have! That is why I really want to look at the logs.... My switch was in P position, so there's no way it could have been... Anyhow if so, DJI app should have told me so...

Hi Gtokarsk!

First - congratulations on not panicking, staying focused and successfully landing your P4 back on shore. Good job in a tense situation!

Based on review of the HealthyDrones report, there was an estimated 9.8 mph wind gust blowing in the direction your craft was drifting backwards during the final minute of flight and your screen shots show you were initially applying 33% forward stick in the first backwards drift photo and then 66% forward stick in the second photo.  Was there a wind as you were landing?  You may not have noticed as I am sure that you were extremely focused on getting your P4 back safely to shore.  My best guess is that there was a wind blowing in the direction you were drifting (backwards), your battery level was critically low and it was trying to land, so just as you had to provide 62% up stick just to maintain altitude you may have to provide more stick than normal both to overcome the wind as well as the P4's determination to land.  It may also be that power to the propulsion system was already being compromised by the critically low battery level and the P4 may have barely had enough power to maintain altitude.  

As another observation, I have learned that with both my P3Pro and my P4, if I am in a hover in a wind of 10+ mph, if I apply only partial right stick flying directly into the wind, my aircraft can drift backwards in the direction of the wind.  Try this the next time you are at a location with 10-15 mph wind and you'll see what I'm talking about.

This is a P3, not 4, but aside from that, yes, I did look at the wind, but unless I am in atti mode, the GPS should have held the position against the wind. If there was an indication that I went into ATTI non gps  mode, I would totally buy what you just said - it would make perfect sense.
Here's a scenario where i flew with serious gusty wind, and did not have such issues, hence my suspicion of something deeper perhaps...
http://healthydrones.com/main?share=RImVBZ
But, just because I have not noticed it before, does not mean it did not happen, so I will agree with you that this is a very good working theory.
Now, if this caused a crash though, I would still consider it a failure of DJI's flight envelope....
So if that is the case, that even such minor wind can have such a stron effect, DJI needs to confirm it, define it, and put this in the manual as a warning of some sort, that if there's wind, and you do a low stick input, the gps lock may not work well.. 10mph wind, in my mind is not enough to cause this issue - but that may be just my expectation. I will do way more testing of this scenario at low altitude, open area, with similar wind, perhaps in "landing" mode....
Thx for the idea!
Oh, I just reread you post, and yes, the low battery and power required to hold position, is another piece that could make sense... So I changed my settings to 20% 10%, I may need to flip them back to 25% 15% perhaps....
Again, if DJI can confirm with pretty good confidence, I'd buy that.. Power management IS also an important part of flying....
GT

I strongly suspect a wind gust at that altitude and you didn't put enough input to go forward to overcome it.  david.p.mann beat me to it but that is exactly what I found before seeing his post.  It's blowing in the exact direction to cause this movement.  I don't know how you managed to get a wind map on a Healthy Drones free account, but here is yours:


Have you adjusted your throttle EXP settings perhaps, and 33% doesn't give you the sort of power you would expect at that percentage?  I notice there were a few warnings of "Mode changed to GPS_Atti".  I think that comes on when you are in "P" mode, but it drops out to ATTI.  Perhaps that is why GPS wasn't holding it stationary?

In your other flight, you didn't seem to be flying hard and fast and fighting against the wind.  You also did not run out of battery.  Perhaps that accounts for no warnings popping up in that case.  But in this flight, you were critically low, and it has a mind of its own in those circumstances.  It will land by itself if it needs to, it will refuse to go into Intelligent Flight Modes ("F") and the batteries could shut down to protect themselves if heavily depleted (e.g. fighting wind). You should have more in reserve for all these unknowns when it comes time to land and you should keep the cutoffs higher than 10% or so.  Good to see you have already raised them.

Congratulations on not having an incident.

Thx, I certainly appreciate you guys giving me support. It is easy to lose confidence!

Well, it is possible, and I never flew with that low power before, but today i did quite a bit of flying in the wind. today I had 4 flights with wind up to 19mph gusts, and 11-14 actual wind, and did not see any of these issues. Mind you, it was not confined area, which usually helps with not over or under controlling, but overall the system flew steady as a rock - even when the radio reported no gps (which actually is wrong, at least according to signal/gps maps)...  So I have even more uncertainty now as to what the heck is going on...
I am really beginning to be tempted to go one rev down in firmware and see what happens...
http://healthydrones.com/main?share=VWcyjL
And no, this is not free HD, that's why i got wind info...
I am definitely not losing my respect for the great technology this baby has, but I just dislike not knowing things for certain...
Anyhow, life goes on, so does flying Every experience like this actually does help in future "emergency" situations, as well as it helps to avoid them, but it is not comfortable sometimes, if the answers are not definitive.
Thx again for the support and helping to evaluate this.
GT

I just attempted to downgrade, no dice:
========== 2014.01.01 00:00:10 remo-con disconnect======
Packet: P3S_FW_V01.07.0060.bin
Result: Abort.
The firmware on the SD card is identical to or older than the current firmware on the aircraft.

Any trickery?

gtokarsk Posted at 2016-5-6 12:33
Thx, I certainly appreciate you guys giving me support. It is easy to lose confidence!

Well, it is  ...

OK, I thought it was a free account because of this:


It seems to be behaving well otherwise, I'd put your problem down to that one-off flight because you were less than the critical battery level.   Don't do it again

The only curious thing left I can see is that GPS_ATTI thing...

gtokarsk Posted at 2016-5-6 12:43
I just attempted to downgrade, no dice:
========== 2014.01.01 00:00:10 remo-con disconnect======
Pac ...

I think a couple of the firmwares won't let you go back.  1.08 must be one of them.

Yes, http://forum.dji.com/forum.php?m ... &fromuid=277621
oh well... I just home a new update comes out soon... too many people are talking about  various issues, and no question, i have a lot of false "gps lost" and "signal issues"....
GT

Yes, so while talking about batteries, how do you guys have your battery thresholds for battery set? I adjusted up to 25% and 15% from 20/10 yesterday. Originally I think It used to be 30/20.... A bit high in my opinion.. but maybe I just experiences why it is so?
HD always displays that way if you share the default privacy settings I guess....
GT

gtokarsk Posted at 2016-5-6 12:56
Yes, so while talking about batteries, how do you guys have your battery thresholds for battery set? ...

Coincidentally, I initially thought the default limits were WAY to conservative, and I dropped them way down to 20 and 10 IIRC.  The next few flights I had to contend with strong wind and quickly learned how fast the batteries would discharge under load, which was a bit hairy when it came to landing.  I have mine on 30 and 20 now.  That suits my flying style where I don't extend too far, I'd have it higher if I was routinely flying a couple of kilometers away and having it RTH on an empty tank...

Was the default setting 40/30?