Return to Home Failure

[imnotreallyscott]

I have never used the phone screen RTH button. Only the controller. And I've never had an issue. If you suspect your phone could be an issue, perhaps the controller button is the way to go.

 

[Chickenhoss]

Compass Calibration - there is an internal compass that senses the magnetic fields of earth, and knows N,S,E,W etc. Calibrating it one time in the general area where you are is enough. If you fly in one spot then go 5 miles away and fly again, calibrating the compass does nothing to help the drone - it already knows where it is (magnetically). You wouldn't calibrate your car's engine computers every day before going out.
IMU Calibration - only needed if prompted to do so - again, you wouldn't do a tune up to your car every morning.

 

[KCVAPOR]

If the phone screen dropped out, then how could you press the RTH on the screen ? Just trying to find out which one you pushed. The RTH button on controller will kick in for the action you want.

The video feed dropped. The functionality of the app was still in tact. Pressing return to home on the screen did not work in the following sequence.

1.) press return home on phone screen
2.) slider bar appears
3.) slide the bar to return home
4.) repeat multiple times while bird hovers in place, clearly still having GPS signal because it was blowing 17mph wind and 200 to 300 feet up and didn't move an inch.

Long story, explained above, I had to completely reboot my phone to get HD signal back once bird was on ground.

I wish I had thought of pressing the return to home button and holding it down (on the transmitter). I had line of sight, was concerned, still had RTF control. SO, once the app return to home did not function after several attempts and waiting. Due to my concern, I immediately flew her straight back to me low and steady before I encountered a complete loss of control. I realize there is a return to home button on the transmitter and wish I had thought to use it at the time.

I flew her in manually and realized the landing assistance was not functioning either once I got 1 inch off the ground full speed down, on uneven surface, in grass. I intentionally did this because upon landing I realized the downward sensors were not functioning and tested them to see if they'd kick in, THEY DID NOT.

I moved around multiple places attempting to get landing assistance (because I was testing it during a problematic flight and manual return) IT DID NOT WORK. IT WAS TURNED ON.

If it was not for the lack of landing assistance, I'd already be telling myself... DUDE USE A RECOMMENDED DEVICE THAT NOBODY ELSE HAS TROUBLE WITH LIKE AN IPAD MINI 4 AND IT WON'T HAPPEN AGAIN!!! (although I personally would use a mount and larger ipad with more current and faster processor for the money...)

The lack of landing assistance is what really makes me question the bird malfunctioning. Especially since rebooting the bird by itself, nothing else, regained landing assistance in a quick hover test to 40ft altitude. Remember, the HD loss at 5 bars with no additional warnings, the lack of landing assistance for no reason...

Again, this could all be the phone that malfunctioned or my watch that did something funny.

I wish I knew more about landing assistance and if the device could glitch/error and cause it not to function. This should be hardwired but it is not... there for it could be an issue with the phone. If I had done more thorough testing perhaps other features would have shown non functional as well. Perhaps the app glitched and caused all this but that is a huge mistake on DJI part if true. Bottom line, I didn't access menus and nothing should have glitched or been turned off during flight.

 

[KCVAPOR]

Compass Calibration - there is an internal compass that senses the magnetic fields of earth, and knows N,S,E,W etc. Calibrating it one time in the general area where you are is enough. If you fly in one spot then go 5 miles away and fly again, calibrating the compass does nothing to help the drone - it already knows where it is (magnetically). You wouldn't calibrate your car's engine computers every day before going out.
IMU Calibration - only needed if prompted to do so - again, you wouldn't do a tune up to your car every morning.

Your car tunes itself up depending on temperature, driving attitude, fuel grade, etc etc even on newer cars based on a route it memorizes and predicts based on your daily commute. EVERY TIME YOU DRIVE IT.

Sorry, I tune cars for a hobby too. I've had many many motors and especially with 2014+ there are so many layers of engine management (minimum of 3 on every motor now) that your statement is false, entirely.

This is why I drive a VW golf 1985 that I tuned myself, diesel, to get 67mpg average at 70%/30% hwy/city driving. Yes It can hit over 110mpg actually but isn't safe on highways with that tune.

The reality of computer driven cars (unlike my 85 diesel that is 100% mechanical with only a start/stop solenoid that technically it doesn't even need to run) is they actually do tune themselves every time they start for the first 40 or so miles of your drive, unless they've determined not much has changed by checking your driving attitude, route, speed, and ignition/fuel/air rates.

 

[KCVAPOR]

I'll extract the flight log as suggested early on.

This will happen some time this evening. The life of a small business owner is busy. Ty for any help diagnosing what I've done wrong.

I appreciate all help and will definitely use the transmitter rth press and hold method in the future. As well as upgrade to an ipad since my phone seems to possibly have something to do with this. Plus receiving texts during flight isn't ideal common sense method lol.

If this is a common USB cable error, it is unlikely due to the cable only being used a few times but possible. Top Notch High Quality USB Cable and new IPAD is on the way as we speak.

 

[Chickenhoss]

Your car tunes itself up depending on temperature, driving attitude, fuel grade, etc etc even on newer cars based on a route it memorizes and predicts based on your daily commute. EVERY TIME YOU DRIVE IT.

Sorry, I tune cars for a hobby too. I've had many many motors and especially with 2014+ there are so many layers of engine management (minimum of 3 on every motor now) that your statement is false, entirely.

This is why I drive a VW golf 1985 that I tuned myself, diesel, to get 67mpg average at 70%/30% hwy/city driving. Yes It can hit over 110mpg actually but isn't safe on highways with that tune.

The reality of computer driven cars (unlike my 85 diesel that is 100% mechanical with only a start/stop solenoid that technically it doesn't even need to run) is they actually do tune themselves every time they start for the first 40 or so miles of your drive, unless they've determined not much has changed by checking your driving attitude, route, speed, and ignition/fuel/air rates.

Point is - which you apparently don't want to listen to others telling you, is you don't have to calibrate it every time you go out. I think I made my point very clear, and nothing false about it. Stop being so arrogant and try listening to others - that's why you began the post to begin with!

 

[KCVAPOR]

Yes I also asked for evidence, examples, and in what way calibrating it for better or same indication on the UI could cause problems, earlier in this very thread.

So sorry to offend but I'm not a fan of sensitive, defensive, nor inaccurate "facts".

Again, so sorry to offend. Not my intention at all. Arrogance is not my intention, simply discovering what I did wrong in this case is my goal.

I've learned
1.) use rth on controller
2.) nobody knows why not to calibrate or in what ways it causes problems not indicated by UI, based on ASSUMPTION. I could argue not wearing your seatbelt will be fine because I don't do it, but then I'm arguing under a fallacy... aren't I?
3.) Wear a body cam at all times when flying UAV, for many reasons, including warranty help and evidence in event of other unforeseen circumstances.

 

[Robin]

As said before please upload your logs

 

[KCVAPOR]

Again, so sorry, offense not intended. Its just the fallacy presented so far of not using calibration at new locations, after bumpy car driven transportation, is failing to make sense to me based on two reasons:

1.) common sense method
2.) lack of evidence, circumstances, and examples of a bad calibration not showing on the user interface (the same one people say if it looks fine then fly, period.)
3.) I'm flying under an LLC, insurance, and license as well as with an attorney on retainer. I can't afford to lose my business to negligence in the event that a court discussion comes up over my operation and calibration of a UAV.

Please provide examples and evidence of calibration gone wrong and why not to fix what isn't broken when you don't know its broken until its in the air and too late.

 

[Robin]

LOOK WE are telling you its an issue to do this everytime.

If you want help provide the flight logs as requested.

I am out of here as you clearly do not want to take said advice.

 

[KCVAPOR]

As said before please upload your logs

Happily, once I return home tonight I will post as promised earlier in this thread. I'm busy running between multiple locations of my business and wish I had the ability to pull over and post it right now but that is not an ability available today.

I look forward to the criticism and education I will receive from my flight log on this issue. TY so much for offering opinions, assistance, and taking the time to deal with me out of your own very busy day. I really appreciate this community and the support it is providing to everyone.


I can also identify with your frustration as I have come unprepared to this discussion. It is just as frustrating for me though, based on lack of information on your typical pre flight checks such as the battery voltage I asked about, the information, and examples on bad calibration or the harm of calibration when indicated better or same as by the UI. The same UI everyone is telling me to trust by spot checking after travel is for some reason not good enough for a calibration at every location. I can not comprehend this logic and it is equally frustrating for me to understand this anecdotal evidence.

I would like links, examples, and information on calibration at every location being a bad idea or even somewhat problematic, in the sense that the risk out weighs the benefits of common sense operation of my UAV in this particular pre flight step.

If I need to build a leveling table, 2 axis rotation, w/balancing weights for the UAV to properly calibrate it I will. Please enlighten me on the failures of calibration that do not show in the UI everyone references to determine when its necessary.

Some background: I am a mechanical engineer from Purdue, work for Rolls R on jet turbine CAD design, an Eagle Scout with very proficient and practiced orienteering merit badge and skills. Please enlighten me in a way I can understand rather than berating me for who I am and how I present myself.

Thank you so much for all the help. I honestly need it as my UAV knowledge and mavic knowledge in particular is completely beginner level.

 

[msinger]

nobody knows why not to calibrate or in what ways it causes problems not indicated by UI, based on ASSUMPTION

It's perfectly fine to calibrate the compass before every flight if you're sure you're calibrating it in an area that is free of all magnetic metal objects. Calibrating before each flight is usually not recommended for the following reasons:

1) Once your Mavic has a good compass calibration stored, it does not forget it the next time you head out to fly. So, you'll just be overwriting a perfectly good calibration if you calibrate again.

2) It's sometimes tough to know if a location you're not familiar with is near magnetic metal objects (perhaps in the ground below). While DJI GO will often alert you when there is nearby interference, it sometimes does not and allows you to successfully perform and store a bad compass calibration.

 

[RavenTBK]

OP says he hit the RTH button several times with no result.

Does OP know he has to HOLD the RTH button for several seconds to get the desired effect?

Based on the description alone provided by the victim, I can only see this as pilot error.

 

[HFMan]

I'm guessing the phone or the app itself messed up- close to crashing. In this case it's best to RTH with the Controller and restart the phone. Unpredictable behavior when the phone or app is close to crashing.

 

[mightyarrow]

This thread would go a lot better if you wouldn't be so demanding and assertive. I think most people reading this feel like you're getting angry.

You keep saying "show me examples, proof, etc". We're not here to prove stuff or provide customer service, we're here for friendly advice. You shouldn't calibrate unless it tells you to. Period. End of story. Take it or leave it.

If you want to discover more about it, do some Googling or searching these forums.

Just relax man.

OP says he hit the RTH button several times with no result.

Does OP know he has to HOLD the RTH button for several seconds to get the desired effect?

Based on the description alone provided by the victim, I can only see this as pilot error.

Same million dollar question i had. I'm going to assume pilot error as well, esp given the lack of details about what he did, how he did it, etc.

 

[PDXteriors]

This guy is definitely on the spectrum.

 

[BudWalker]

Hello.

I've got about 5 flights of time on my Mavic now. Yesterday I ran into a situation and I'd like some information on what to do if this happens again.

1.) I was Line of Sight
2.) I was at about 200ft - 300ft altitude
3.) My transmitter was not obstructed by any power lines, metal, or otherwise
4.) I was not in a city, I was in a rural area with 18/19 satellites, full bars on all accounts, but my HD Signal with full bars was blinking (does this mean interference?) What does the HD Signal do?
5.) I was flying on a Samsung S7 Active attached to controller, no aftermarket accessories on transmitter or bird.


Ok so I was lining up a shot (it turned out bad... but learned a lot). I flew direct line of sight over a soybean field with the transmitter paddle antennae properly aligned to the bird (I fly a lot of RC)

Without warning (unless the blinking HD signal with full bars was a warning, please explain in detail) the display screen dropped out (about 500 - 700 feet away, 200 - 300 feet up LoS).

I immediately hit return to home on the phone screen, nothing happened. I repeated multiple times. The Mavic just sat there hovering in the sky.

I had about 68% battery so I wasn't worried. I had to fly the Mavic back LoS like I normally do with my non UAV birds.

Here is the next weird part, when I landed the Mavic it did not hesitate to just hit the ground full speed. Normally it will sense the ground, hover, and then land. This time it decided it would just flop down on the ground without even assisting landing. Luckily, I did not strike the ground hard with it on landing but I could have.

After I had it on the ground I turned it off, then back on, as well as the transmitter (in proper safe sequence). Again, standing right next to it no display, home point would not set (I click to set home point but the voice on controller did not say anything). I took off, hovered at 40 feet for about 60 seconds, then landed with assistance working (proper mavic landing).

Finally, I rebooted my phone, mavic, controller... and the issue did not happen again after.



WHAT THE HECK??? I properly set home point every flight, calibrate IMU, Compass, and Gimbal every time I move to a new location. I always hover 40 feet, straight up from set home point.

RTH, obstacle avoidance, wasn't in sport mode... pretty much everything was set so it should have been able to return to home.

What happened? What can I do better? Terrified to fly out of LoS now... even with a spotter.

Please retrieve and provide the .txt for this flight as requested by @msinger . I suggest that you also retrieve and provide the .DAT for this flight which is on the Mavic itself. (There may be a .dat on the tablet but that is not the right one). Since the app crashed the only way to know what happened during that interval is through the .DAT. Look here for info about retrieving the .DAT. It'll be large so you'll need to Dropbox or GoogleDrive it and provide a link here.

From your description it seems unlikely that there was a compass issue. But, if there was it's likely the .DAT will provide the necessary data.

With regard to the comments made about compass calibrations I've done some experiments and research over the last 18 months or so. My observations:
1) It's very difficult to get a bad compass calibration. I did an experiment with my P3 where I attempted to calibrate next to a large metallic object (my pickup). If the P3 was too close the Go App would complain about interference and reject the calibration. After several attempts I knew how close I could get and still have the calibration accepted. That "bad" calibration wasn't bad enough to cause a flight problem.

The other method I used was calibrate with an allen wrench attached to an adjacent leg (the compass is in one of the legs). After the calibration the wrench was removed which yielded a P3 with a bad calibration that probably would caused an incident had I flown it.

I suspect that under just the right circumstances it may be possible to unknowingly obtain a bad calibration. So why risk it.

2) With one exception I have never seen an incident caused by a bad calibration supported with data or some other compelling evidence. I've been looking at compass related incidents for well over a yer and that one exception happened last week. Actually, that incident was likely the result of a hardware change or partial failure that got "fixed" with a calibration. Take a look at
Fly Away
if interested.

3) It wan't stated explicitly here but some may believe that a calibration is necessary at a new location in order that the geomagnetic declination can be determined. The calibration procedure for the Mavic, P3, etc does not and can not determine the geomagnetic declination. The only thing that can be determined about the local geomagnetic filed is it's strength. I suspect the P3 was more sensitive to the geomagnetic strength than is the Mavic.

BTW, I've never calibrated my Mavic's compass or IMU.

If anybody is still reading this and is interested you might be interested in the MagData player in CsvView.
http://www.datfile.net/Doc/MagDataPlayer.pdf
Basically, it presents magnetometer data in a way that would expose a bad compass calibration. It's eye candy for geeks, but it's good eye candy.

 

[Glamas]

I had the same problem.
I set everything right. I made a flight, I was 3,100 meters and I lost the control signal.
The Mavic did not do k RTH, he kept trying to go up, even after reaching the maximum altitude (checked in the log).
I was with 69% battery, it stayed like this until the battery reached 10% and landed. I needed to get my drone in a place of difficult access, I found it because I used the Find My Drone that was very precise.
I think it's a problem with the 0900 Firmware.
I've downgraded to the 0700.
I've seen several identical reports.
Sorry for my English, I'm Brazilian and I'm still learning.

 

[KCVAPOR]

OP says he hit the RTH button several times with no result.

Does OP know he has to HOLD the RTH button for several seconds to get the desired effect?

Based on the description alone provided by the victim, I can only see this as pilot error.

Sorry trying to get flight log things posted up, been looking at them on some upload sites. No, I stated I used the RTH on the phone/app and completely forgot the RTH button is even on the controller. Was more worried about flying LoS back in before it could possibly lose more control.

 

[KCVAPOR]

DJI Flight Log Viewer - PhantomHelp.com

So this log ends 700ft from home, but no I never retrieved my bird out of that field. I flew it back LoS w/no camera and landed it safely as I explained to begin with.

All my numbers stated earlier were **** close, didn't know my memory still worked until now lol.

No messages are stated, as I thought. No warnings etc etc. Just 5 bars of HD blinking, then nothing w/out warning and no landing assistance either upon flying it in.

Confused what happened.

Like I said, my app was still functional, just no picture, RTH on it didn't work, and it wouldn't reconnect at all until I completely rebooted my phone (which I rebooted before flying anyway).

Restarting the app did not help, restarting the controller did nothing, restarting the bird did nothing. Again, multiple restarts accomplished nothing until I completely rebooted my phone.

So I'm looking at firmware and my phone now, which will be replaced by ipad mini 4 cellular very soon. Hopefully this doesn't happen to someone who is out of LoS.