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Triple yellow status warning lights. I need to know!
1243 19 2017-8-7
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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Hi all, great forum, it has quenched my thirst for several pieces of information regarding my new Mavic; keep up the great work.
  
I love my Mavic and I’m impressed with the tech and reliability that I’ve experienced thus far; as a 45 year old electronics tech I’m not that easily impressed either!

  
However, my technician curiosity is killing me. Someone help me with the observation below please!  
  
My Mavic's flight performance has been pretty much faultless. However I keep getting intermittent ‘fast-triple’ yellow status lights. I know these lights indicate loss of RC connection, but this doesn’t really add up as I’m not losing RC control and it is happening at close range with no warning messages. Some non-conclusive observations below:

  
1.   1.  I initially thought it was happening with only one of my batteries. However, it is happening with both.
  
2.   2.  No other warning messages on DJI GO.
  
3.   3.  Full RC signal strength on RC during occurrences. No noticeable negative flight performance.
  
4.   4.  Actually seems to be most prevalent when flying over my own (controller) location. Especially when descending from altitude.  
  
5.   5.  I’m pretty savy at analysing the flight logs and can’t spot anything.
  
Go on, give me a steer, Mavic ninjas!    

2017-8-7
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I am the E
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Luxembourg
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Did you adjust the antennas, RC and antennas flat parallel to the AC?

2017-8-7
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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Thanks Intern Pilot, It's something that crossed my mind, particularly with the Mavic crossing / going overhead and my body possibly shielding the signal.  The Mavic would have been above the tips of the antennas; though I would still be surprised if it lost signal at such a short range. Either way, I have still experienced it with the Mavic 'broadside' to the RC Antennas (most notably with it above 50M alt). I'm wondering if the RC / Mavic actively adjusts it power, and crossing overhead is catching it out.  I'm still not entirely convinced it's a loss of RC signal indication; could it be something else?   
2017-8-7
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Eagle_Eye
First Officer
Flight distance : 4137720 ft
United States
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I also have the same observation w/ my MP, no warning/notifications whatsoever.
DJI what is this, anyone pls chime in.
This got nothing to do w/ antenna orientation.
2017-8-7
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AG0N-Gary
Captain
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United States
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Its isn't so much your body that is blocking the signal, but that can happen if the signal is weak already.  You didn't say what "branch" of electronics you're in, but if it was communications, you would likely know what cone of silence is.  Google "antenna cone of silence".  It the tips of the antennas (RC and Mavic) are pointed at each other, they are receiving a very reduced signal.  Here's a good illustration of what happens at VHF/UHF and higher frequencies.  Hopefully this link works.   https://goo.gl/images/KX8VdZ
2017-8-7
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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Nice link AG0N-Gary, my expertise is comms and radars, so familiar with antenna propagation (no arrogance though, your input is genuinely appreciated and considered). If it was just when overhead, I'd be content. However, after my last flight and running some 'crude' experimentation I'm not convinced.  I'm going to do some more tests with rapid changes of altitude as this seems to trigger the event. My gut feeling is this is just sporadic interference. It is quite possible that very short periods of interference or signal loss (possibly milliseconds) could trigger the warning lights, with no other symptoms.

It appears the Mavic's ability to deal with interference in a busy frequency spectrum is amazing though.
2017-8-7
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DJI Susan
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Double checked with our engineers, the two IMU may be disagree with each other at that moment. Could you refer below and export the flight log for further analysis? Our engineers would like to look into it. Thank you in advance!

The way to export the Main Control Data and upload to Dropbox and send us the link:
1.Download and install DJI assistant 2 via http://www.dji.com/mavic/info#downloads
2.Connect aircraft and PC,and power on the aircraft
3.Operate DJI assistant 2, find flight record and save
2017-8-9
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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Thanks DJI Susan. I've uploaded a flight that included some occurrences of the incident.  

https://www.dropbox.com/s/3d3wbv6dmgoe89u/FLY069.DAT?dl=0
2017-8-9
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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DJI Susan Posted at 2017-8-9 00:36
Double checked with our engineers, the two IMU may be disagree with each other at that moment. Could you refer below and export the flight log for further analysis? Our engineers would like to look into it. Thank you in advance!

The way to export the Main Control Data and upload to Dropbox and send us the link:

Thanks DJI Susan. I've uploaded a flight that included some occurrences of the incident.  

https://www.dropbox.com/s/3d3wbv6dmgoe89u/FLY069.DAT?dl=0
2017-8-9
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DJI Susan
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Fingers Posted at 2017-8-9 13:42
Thanks DJI Susan. I've uploaded a flight that included some occurrences of the incident.  

https://www.dropbox.com/s/3d3wbv6dmgoe89u/FLY069.DAT?dl=0

Received with thanks! I have forwarded to our engineers to review and analysis. We will contact you once there is any update.
2017-8-13
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DJI Susan
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DJI Susan Posted at 2017-8-13 20:30
Received with thanks! I have forwarded to our engineers to review and analysis. We will contact you once there is any update.

Confirm with our engineers that triple yellow LEDs appear when high-frequency vibration was detected by aircraft IMU. During the flight, the high propeller rotate speed and propeller vibration will result in excessive body vibration.
2017-8-21
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Eagle_Eye
First Officer
Flight distance : 4137720 ft
United States
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DJI Susan Posted at 2017-8-21 22:36
Confirm with our engineers that triple yellow LEDs appear when high-frequency vibration was detected by aircraft IMU. During the flight, the high propeller rotate speed and propeller vibration will result in excessive body vibration.

Can you please elaborate more on this?
Which large propeller, they'll the same size isn't it?
Basing on that conclusion and analysis what is the remedy/fix for this?
I haven't had this observation w/ my MP before and I got zero crashed so far.
Does any sort of IMU calibration needed @ this point?
2017-8-22
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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Thanks for the response from DJI Susan and the engineers.  Is there any recommendations?  or should I just keep flying and take no notice of the intermittent warning?  

2017-8-23
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DJI Susan
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Eagle_Eye Posted at 2017-8-22 03:39
Can you please elaborate more on this?
Which large propeller, they'll the same size isn't it?
Basing on that conclusion and analysis what is the remedy/fix for this?

The excessive aircraft vibration will alert the IMU. I would recommend you to fly smoothly. No worries.
2017-8-24
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Fingers
Second Officer
Flight distance : 1321293 ft
United Kingdom
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DJI Susan Posted at 2017-8-24 01:32
The excessive aircraft vibration will alert the IMU. I would recommend you to fly smoothly. No worries.

Thanks DJI Susan.  I think your engineer's rationale makes sense.  

I did some further experimentation this morning.  Lovely calm day, and I've 'dialled down' many of my settings for smooth video. I had a couple of instances of the  yellow flashing lights. On both occasions they were when decending quickly from altitude and braking from pitching forward.

I'm sure we've all noticed that the Mavic has to work hard when decending from altitude due to it flying into its own prop wash (the Mavic deals with it very well in my opinion).  I'm putting the vibrations down to this additional turbulance and some braking.   

I'm starting to gain real confidence in my Mavic (and my skills) now.  It's flight performance has been excellent.  Thanks for helping me get some conclusion over this matter.  Love my Mavic more each day.
2017-9-3
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MARSAN
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Eagle_Eye Posted at 2017-8-22 03:39
Can you please elaborate more on this?
Which large propeller, they'll the same size isn't it?
Basing on that conclusion and analysis what is the remedy/fix for this?

Where did you read "large propeller"?
2017-9-3
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Eagle_Eye
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MARSAN Posted at 2017-9-3 03:51
Where did you read "large propeller"?

Obviously something was edited otherwise I will not even mentioned it.
I only pointed out that comment about the props, coz we knows and can see that there's no large props.
That's why I'm asking for elaborations.
2017-9-3
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MARSAN
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Eagle_Eye Posted at 2017-9-3 04:22
Obviously something was edited otherwise I will not even mentioned it.
I only pointed out that comment about the props, coz we knows and can see that there's no large props.
That's why I'm asking for elaborations.

That's highly interesting, because the post quoted in your post, does not contain the words "large propeller".
Dangerous forum...
2017-9-3
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Eagle_Eye
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MARSAN Posted at 2017-9-3 07:18
That's highly interesting, because the post quoted in your post, does not contain the words "large propeller".
Dangerous forum...

it is   highly interesting.
2017-9-3
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DJI Susan
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Fingers Posted at 2017-9-3 03:45
Thanks DJI Susan.  I think your engineer's rationale makes sense.  

I did some further experimentation this morning.  Lovely calm day, and I've 'dialled down' many of my settings for smooth video. I had a couple of instances of the  yellow flashing lights. On both occasions they were when decending quickly from altitude and braking from pitching forward.

Thanks for your positive feedback. Wish you have a nice time on flying Mavic.
2017-9-5
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