Return to Home Failure

[KCVAPOR]

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.

 

[msinger]

What happened?

Check out your TXT flight log to see if it explains what happened. You can upload and view it online here. If you'd like other people to review and comment on your flight log, then please post a link back here after you upload it.

 

[KCVAPOR]

OK. Will do since I realize my recollection of events is only HUMAN.

What does the blinking HD Signal with full bars mean? What is the HD Signal responsible for? Please explain in detail.

 

[Robin]

HD signal is the video link.

I would NOT calibrate at every new location.
Only if it tells you to do. Which in my case never.

 

[KCVAPOR]

Also, in the event I did not have LoS (I know I know but **** can happen) ... What would the bird do if I had just let it hover and not flown LoS? My understanding is a failsafe kicks in upon low battery, in which case it either hovers or returns home depending on the setting selected.

Does the landing assistance turn off for no reason very often like I witnessed? I thought it worked off of sensors independent of HD Signal, since it normally refuses to hit the ground no matter what I do.

 

[Robin]

Never had that, but you need to check your settings.

And loss of control signal and what it does again depends on your settings.

 

[KCVAPOR]

Is there a setting I can toggle for downward sensors/landing assistance? I am unaware of any setting that allows me to turn crash mode on, so to speak.

 

[KCVAPOR]

The only thing I noticed during pre flight checks (I check EVERYTHING, Calibrate EVERYTHING, and TRIPPLE CHECK EVERYTHING!!!!) my battery was at 4.3v across all cells. Is this normal or was this cell over charged??? What range of full charge do you guys see on your battery during pre flight checks? My understanding is 4.2v is the limit, however most of my RC's do fly frequently with lithium polymer cells charged to `4.4v fresh off the charger (I know batteries, sell electronics that run on lipo/li ion, etc)

I'm just curious what your batteries show during pre flight check. Please elaborate if necessary.

 

[Robin]

As I said I dont think you should calibrate every time, yes check settings but not calibrate.

Yes there is a landing assistance than can be turned on or off.

 

[KCVAPOR]

HD signal is the video link.

I would NOT calibrate at every new location.
Only if it tells you to do. Which in my case never.

Why would you not calibrate at every new location? This is common sense flying to me. When I researched this bird I assumed it was mostly user errors causing fly away but I now realize this bird is very unpredictable all on its own. The fly away videos, posts, and complaints are the reason I believed in common sense flying methods.

Please elaborate on what the pro's/con's of calibration are. I do not comprehend how I should go against common sense pre flight methods as I've done with all my birds since the old days. If there is a problem caused by calibration, please explain why it happens and how to avoid it.

 

[Robin]

First of all you dont need to.
The manual says only if app tells you.
It takes time and power which is better used flying.
Thirdly you risk adding a bad calibration into the mix doing it everytime.

I never had to calibrate, even though it went from China to USA to EU.

 

[KCVAPOR]

My belief is that the lack of common sense flying is the reason for so many crashes, regulations, and losses. For example, had I not been LoS I would have potentially lost my bird, or crashed it before retrieval.

I don't understand what a bad calibration is. If the sensors indicate good calibration, then your efforts should not affect anything negatively. Also, I have yet to see the indication through the UI that my calibration caused less accuracy, actually quite the contrary. Green, is green. However, less green the better as well according to the UI itself.

I am relying on the very same user interface as you. I am determining the calibration is good, then calibrating it to see better than what it started at, or same. Either way, so far, the user interface has not suggested my calibration was bad, or that the bird was worse off than when I started.

Further more, if I'm flying near a giant rock filled with minerals and metals of different composition, with different signals and towers around me affecting magnetic field. It seems contrary to common sense to not calibrate. The composition of the landscape and magnetic field changes at every new location.

My Karma UAV has yet to malfunction. It flies like a drunk weed wacker, but has yet to respond unreliably. It has no range, no sensors, no features, but has yet to let me down like the Mavic has only a few flights in. I am aware of the recall. However, I don't buy ANY machine the day it comes out. I've learned from years of RC, wait for the revision. So I never dealt with that issue, nor any issues on my cars (automobiles are always revised heavily right after release) etc etc. Following this common sense method with my Mavic I thought I would be safe, I was wrong.

I am either wrong that the Mavic is reliable after many updates, or I am wrong in how I operate this bird. I am here to find out what is wrong!

 

[msinger]

Please elaborate on what the pro's/con's of calibration are.

Check the Compass Calibration Guide for the best advice on this topic.

 

[msinger]

What does the blinking HD Signal with full bars mean? What is the HD Signal responsible for? Please explain in detail.

Per the Mavic manual:

 

[KCVAPOR]

Please explain what a bad calibration is, when indicated well and good by the UI.

Please give examples and situations in which this has occurred. I would like to know more about calibrating for worse, even when indicated better by the UI.

Nevermind, I will pursue this through the above link posted, then return with a more enlightened attitude on this topic.

 

[KCVAPOR]

Per the Mavic manual:

View attachment 16113

I have about memorized the manual.

However, there were no additional indications. There were 5 bars, the bird was well within its reasonable range, the transmitter was aligned properly per typical paddle antennae orientation.

Like I said, even after it was on the ground and the bird was rebooted, then the bird and the transmitter rebooted/app restarted... still no HD signal connection was being offered.

Only after restarting my phone with above mentioned as well, did it return HD signal. This leads me to believe my phone may be causing issues with HD signal and is not compatible with this bird. I have since flown with my blue tooth watch turned off, in hopes this was the issue but am probably going to invest in a cellular ipad to rule out this possibility.

Yes, I did and always do reboot my phone before flying to ensure it is happy and ready. However, it was my mistake not powering off my watch before this flight.

The problem is my landing assistance did not function, while definitely turned on. This leads me to believe the bird was malfunctioning heavily since it happened as well during the problematic flight. However, in a quick hover test to 40 feet, the ground sensor did work after just rebooting the bird and nothing else adjusted in settings, with no HD signal. Like it should have the entire time.

 

[Clinton1]

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).

Do you mean the phone screen ?

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.

RTH on the phone screen, or the RTH button on controller ?

 

[Clinton1]

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.

 

[LongRifle]

My belief is that the lack of common sense flying is the reason for so many crashes, regulations, and losses. For example, had I not been LoS I would have potentially lost my bird, or crashed it before retrieval.

I don't understand what a bad calibration is. If the sensors indicate good calibration, then your efforts should not affect anything negatively. Also, I have yet to see the indication through the UI that my calibration caused less accuracy, actually quite the contrary. Green, is green. However, less green the better as well according to the UI itself.

I am relying on the very same user interface as you. I am determining the calibration is good, then calibrating it to see better than what it started at, or same. Either way, so far, the user interface has not suggested my calibration was bad, or that the bird was worse off than when I started.

Further more, if I'm flying near a giant rock filled with minerals and metals of different composition, with different signals and towers around me affecting magnetic field. It seems contrary to common sense to not calibrate. The composition of the landscape and magnetic field changes at every new location.

My Karma UAV has yet to malfunction. It flies like a drunk weed wacker, but has yet to respond unreliably. It has no range, no sensors, no features, but has yet to let me down like the Mavic has only a few flights in. I am aware of the recall. However, I don't buy ANY machine the day it comes out. I've learned from years of RC, wait for the revision. So I never dealt with that issue, nor any issues on my cars (automobiles are always revised heavily right after release) etc etc. Following this common sense method with my Mavic I thought I would be safe, I was wrong.

I am either wrong that the Mavic is reliable after many updates, or I am wrong in how I operate this bird. I am here to find out what is wrong!

You have sound policy on minimizing risk, but I believe it's also wise to mix in the old adage "If it ain't broke don't fix it." I've had my Mavic since early December (ordered a week after it was announced). I've never had a problem with it. I used to calibrate the compass before each flight session. I don't do that anymore when I realized it wasn't necessary. I've never calibrated the IMU as it has never prompted me to. I agree with the other posters. A bad calibration may have caused your issues. Your screen going blank may have been the app crashing, so in my opinion you may have had two separate issues.

 

[Clinton1]

....or did your video feed drop out, but the DJI Go app was still up and running ?