DJI Mavic, Air and Mini Drones
Friendly, Helpful & Knowledgeable Community
Join Us Now

Speed error

ugabuga

New Member
Joined
Aug 22, 2017
Messages
4
Reactions
0
Age
40
Location
Bulgaria
Couple of days ago my Mavic issued Speed error and as visible from the log also Yaw error and Compass error in a short period of time at the beginning of the flight. It felt like it was drifting uncontrollably for couple of seconds. Then everything came back to normal and there were no more issues during the flight. I have no other flights since then. What may be causing these errors? How dangerous are they?

DJI Flight Log Viewer - PhantomHelp.com
 
I lost my drone to the depths of a lake. When I checked out the flight log it had the message "Speed Error" right when it started spinning and falling to the water.
 
Anyone experienced Speed error? Is it only me?

I get a Max Motor Speed issue when pushing both sticks full forward, esp. in sport mode. If you don't let off, it soon becomes a Battery Discharge Error (or something like that) and the AC will just stop and hover until it recovers. That's a real "pucker' moment, I tell you what! LOL.
 
Max Motor Speed is totally different stuff than Speed error. I had a chat with DJI support and they said it may happen when there are not enough GPS satellites or the compass is not calibrated. It is connected with the actual speed of the aircraft, not the motors. They recommended calibrating the IMU and compass. I have never experienced this error since then. One of my "conspiracy" versions is that magnetic storms caused by extra solar activity altered the normal work of satellites or the device that day.
 
I got a speed error today and the MP appeared to flip. not sure as I looked up just as it happend. at this moment it said ATTI mode then went back to GPS. airdata shows the speed error warning.
 
I got a speed error message while in the process of an Auto Land. The MP suddenly moved sideways into a tree. This was not drift, but a semi-fast movement. I sustained prop damage and had to clean the dust from the motors and gimbal. I'm going to recalibrate everything as if I'm starting with a new unit. Here's the log if anyone can advise further

DJI Flight Log Viewer - PhantomHelp.com

Thanks,
ChasD
 
I got a speed error message while in the process of an Auto Land. The MP suddenly moved sideways into a tree. This was not drift, but a semi-fast movement. I sustained prop damage and had to clean the dust from the motors and gimbal. I'm going to recalibrate everything as if I'm starting with a new unit. Here's the log if anyone can advise further

DJI Flight Log Viewer - PhantomHelp.com

Thanks,
ChasD

my first thought was poor GPS and when GPS updates to a new location it results in fake very high speed (speed error) and might cause the drone to re-position itself (fly sideways into the tree).

However looking at the log, there were some very violent inputs a few seconds before the speed error.

W7t0gUO.png

36rLF

@204 there is 100% forward and 80-90% sideways input for ~1.5 seconds.
@205.5 the sonar detects something (hit the tree?)
@206 100% down and 100% rotation input
@207 it's on the ground

during the rest of the flight you flew smooth, so I expect you might have bumped the controller during the autolanding, causing some violent movements and the crash, resulting in a speed error.

I'm no expert. when one of the experts looks at the log they can confirm or deny the above.
 
laurens23...thanks for the input. The MP was in auto land when it started moving to the right. It was not a drift but a pretty fast movement. I tried to go forward to miss the tree, but I was definitely in the panic mode at that point.

Here is a video clip from the Flight Record. It shows the sideways movement right after the MP shifts into Precision Landing. I jammed the sticks to the off position after the MP was dancing on the ground.

Dropbox - IMG_0161.TRIM.MP4

(The link should allow downloading from my Public File area)

I really appreciate your help. Can you advise how you got the graphing....possible link or app?
 
laurens23...thanks for the input. The MP was in auto land when it started moving to the right. It was not a drift but a pretty fast movement. I tried to go forward to miss the tree, but I was definitely in the panic mode at that point.

Here is a video clip from the Flight Record. It shows the sideways movement right after the MP shifts into Precision Landing. I jammed the sticks to the off position after the MP was dancing on the ground.

Dropbox - IMG_0161.TRIM.MP4

(The link should allow downloading from my Public File area)

I really appreciate your help. Can you advise how you got the graphing....possible link or app?

First off, the emergency shutoff is sticks down and in, not down and out like you do at 10sec into the video.
edit: i checked the manual and both down and in as well as down and out should work.

Precision landing "looks" at the takeoff spot after ascending to 30ft at takeoff. When coming back to land the drone will initially use GPS. then when it gets below 30ft it might re-position for the precision landing. in your video the drifting starts at ~2sec and 30ft altitude. (Personally I never use precision landing so I have no actual experience with this feature) This might be the cause of the initial drifting.

Or maybe the initial drift was because of a GPS re-positioning, or maybe a big wind-gust, or some other cause. more experienced analysers can probably tell you which one.

In any case, at 3 sec in your video the drone is drifting right and you are making it worse by putting in 80% right and 100% forward on the stick. Maybe the drone was facing you and you got confused by the revered orientation and applied aileron in the wrong direction?

I used this to get the graph from the log file data
 
Last edited:
  • Like
Reactions: Tinmania
Thanks again....I think you are right in your assessment. I was definitely in the panic mode when it started to drift. I’m going to look at the actual video and see if it matches the flight data evidence. My recall is that I did not have any forward movement, but I may have been into the tree by that time.

I’d like to think this was a malfunction but the evidence doesn’t support that premise. Statistically speaking, I have to admit to pilot error and I’m trying to learn from the experience.
 
I got a speed error message while in the process of an Auto Land. The MP suddenly moved sideways into a tree. This was not drift, but a semi-fast movement. I sustained prop damage and had to clean the dust from the motors and gimbal. I'm going to recalibrate everything as if I'm starting with a new unit. Here's the log if anyone can advise further

DJI Flight Log Viewer - PhantomHelp.com

Thanks,
ChasD
Were there cars parked here under the Mavic when this happened?
upload_2018-4-11_10-41-41.png
 
No...my truck was parked several spaces away....There were cars in the parking lot, but none were close when the incident occurred.
Usually I would be thinking some kind of compass error problem. But, there aren't any of the usual indications. Maybe the problem was caused to the Precision Landing system being confused. There were 3 attempts at a precision landing with first one directly over the HomePoint.
upload_2018-4-11_11-52-6.png

I kinda think this was the problem, but if you want to pursue the compass error explanation we'll need to have a .DAT. Look here and here to see how to retrieve a .DAT.
 
Lycus Tech Mavic Air 3 Case

DJI Drone Deals

New Threads

Forum statistics

Threads
130,097
Messages
1,549,221
Members
159,150
Latest member
ScottCrudge