Divorce is inevitable, MM and me

[David2111]

On Sunday 12th January MM and me had a bit of flying time around our local river in Armagh Northern Ireland. Weather was good. Wind was around 10mph well within MM capabilities.



11 minutes into the flight, the drone dropped 27ft and almost hit the water, it failed to respond to my power inputs on the left stick. The drone was sent back and the flight log also sent to DJI.

DJI responded that the drone was OK.

When asked for their analysis of the flight log it was as follows:

Dear David,

Thank you for your message.

Our Data Analysts have checked the data you provided. Please see their conclusion below:

"1. The aircraft worked under GPS mode and did not respond well to the pilot's command due to the strong wind;

2. Flight Time T=05:16,Relative Height H=13.6 m,Distance to Home Point D=31.8 m,there was no pilot’s input, the aircraft tilted 11.6 degrees rightward to resist the wind,which indicates that there was strong wind affecting the aircraft;

3. T=05:31,H=12.3 m,D=34.1 m,the warning of “High wind velocity. Fly with caution and land in a safe place ASAP” appeared;

4. T=11:00,H=3.7 m,D=23.5 m,the aircraft descended because propulsion was affected by the strong wind;

5. T=12:47,the aircraft landed on ground and no crash incident happened "

If there is anything else we can do for you, please let us know. We will be happy to assist you.

Kind Regards,

Stefan

Customer Service EU
DJI Europe

So, at 5:31 I got a message saying High wind velocity, I honestly cannot remember, but if I did, I did. Apparently during the entire flight, that was the only message I got regarding High Winds.
At 11:00 "the aircraft descended because propulsion was affected by the strong wind"

The MM did not get blown away from me or anywhere else, it simply descended.

That's it case closed.

For me, its the end of me and the MM, I simply cannot put a drone in the air if I can't control it.

There are numerous other posts on this forum and the DJI forum as well citing MM falling from the sky.

I think there is a problem, a serious problem with the control systems of the MM, perhaps lack of power, I don't know but I am very, very glad I still have my Mavic Air.

 

[netsonic]

Mate, just for your own sake and for ours too, please post the log here. Someone with a paid Airdata account might upload it and share it here. This will show your altitude as well as the wind at that altitude. 12m high is not very much, however the suspicion is that the wind you see above is at the ground level and up in the air there is another speed. Please post the log and we'll see it black on white.

Help us to help you!

 

[Phantomrain.org]

One of the first things we noticed at Phantomrain was that the sensors on the bottom of the Mini were going to be a problem flying low over the water do to alt change.

Most likely do to how sensitive they were to reflection , sun light, and bounced light.

When we designed the Wet Suit for the Mini we created a mask that would create some depth to protect the sensors from unwanted reflections off the water and from any light bouncing which was an improvement.

However the best way was to completely cover the sensor using the Plug right into the Mask.
Since than we have not had any issues , so those sensors may be the problem for these unexpected loss of alt in some of these cases.

In any case I think it is more than the wind that is causing these incidents.

Phantomrain.org
Gear to fly you Mavic in the rain.
Coal

 

[RodPad]

@David2111, upload your log here or to this websight: DJI Flight Log Viewer | Phantom Help

Rod

 

[chriscuk]

I've seen 1-2mph winds at ground level but 15m up a steady 20mph wind. Local weather map predicted 4mph winds.

I would love to see the logs and we can see what airdata or similar say about the wind claims.

They do seem to have a bit of a habit of wanting to take a bath though There are quite a few people who have had this happen.

 

[David2111]

Flight log here: DJI Flight Log Viewer - PhantomHelp.com

Please note, I hand launched the drone about 13 feet above the level of the river.

Around 11 minutes into the flight the drone descended 4 feet without my input, I then reacted and despite full throttle the drone continued to descend until it reached minus 11 feet. I estimate the drone was about 30 feet above the river level before descending, my calculations are:

Start of descent = 16 feet
End of descent = -11 feet
Height above river at end of descent, about 3 feet
30 feet

This is a dronie, taken just before the failure, notice the water is calm and very, very little wind.

The DJI report, point 4 says propulsion failed due to strong wind, it will be interesting to see is anyone can throw light on this, the only mention of strong wind being reported was at 5.16 and 5.30 into the flight.

Having flown a Spark and Mavic Air for over 3 years I can honestly say I have never experienced control issues like this one.

 

[dronedronedrone]

I don't have the logs with me, but I experienced a similar phenomenon the other day.

I was flying over the ocean, winds were very low according to app at my altitude (experienced no high wind warnings indicating gusts either). I was 200 ft off the ground.

Did a fly out over the ocean and was rotating to return home. Upon rotating I noticed the Mavic Mini drop in altitude very quickly, almost 50 ft. I was able to adapt, fly back up, while accelerating forward home but it was jarring. If I was closer to the water I probably would've crashed.

Only time I've experienced this.

 

[Phantomrain.org]

Flight log here: DJI Flight Log Viewer - PhantomHelp.com

Please note, I hand launched the drone about 13 feet above the level of the river.

Around 11 minutes into the flight the drone descended 4 feet without my input, I then reacted and despite full throttle the drone continued to descend until it reached minus 11 feet. I estimate the drone was about 30 feet above the river level before descending, my calculations are:

Start of descent = 16 feet
End of descent = -11 feet
Height above river at end of descent, about 3 feet
30 feet

This is a dronie, taken just before the failure, notice the water is calm and very, very little wind.

The DJI report, point 4 says propulsion failed due to strong wind, it will be interesting to see is anyone can throw light on this, the only mention of strong wind being reported was at 5.16 and 5.30 into the flight.

Having flown a Spark and Mavic Air for over 3 years I can honestly say I have never experienced control issues like this one.

Once again I do not think it was the wind that is causing this behavior.

You mention you hand launch , this begs the question did you ever put the drone down on the ground before take off.

Other than that this is a good example of a possible reflection challenging the sensors.

Try that same flight with the Sensor covered and see if the outcome does not change.
We found the sensors right away to be an issue.

Phantomrain.org
Gear to fly your Mavic in the rain.
Coal

 

[RodPad]

Hum,
11m 0.5s It starts going down, and you telling it to go up, with a twist
11m 4.9s It starts going up lost 23' in 4.5 secs.

Well anyways, the log file must be the correct one.

Rod

 

[David2111]

Hum,
11m 0.5s It starts going down, and you telling it to go up, with a twist
11m 4.9s It starts going up lost 23' in 4.5 secs.

Well anyways, the log file must be the correct one.

Rod

Yep, I thought it was going for a swim, the bottom sensor detected the water and it "bounced" up about a foot. Then I got a bit of control back, it was very sluggish flying it back.

 

[barrybcar]

I’m thinking that if I knew I was going to fly over water with the MM I would do what @Phantomrain.org said and cover the bottom sensor.

 

[dronedronedrone]

Is there any downfall to covering sensors / how does one do this?

Thanks!

 

[grahamjohnson10]

The VPS is active up to 10M / 32.8084 Feet, so it seems to me that when over water be 33 feet or more up.

 

[netsonic]

Is there any downfall to covering sensors / how does one do this?

No downfall except that you need to know how to land via stick gently. You can use tape to do it.

 

[David2111]

The DJI support log has no mention of sensors.

They tell me the drone tilted 11 degrees at 5 minutes into the flight followed by a "High Wind" warning. They have not told me anything regarding the telemetry of the drone at 11 minutes, simply that:

"4. T=11:00,H=3.7 m,D=23.5 m,the aircraft descended because propulsion was affected by the strong wind;"

I have asked them to tell me the tilt of the drone at this stage, it dropped four feet with no input from me. From their analysis, a gust of wind at 5 minutes flight time affected the drone 6 minutes later at 11 minutes.

I am not buying into that, something affected the propulsion of the drone and it could not maintain height.

The bottom sensors worked perfectly at minus 11 feet they detected the water, at this point the drone was about 2-3 feet above the water and it "bounced upwards" same affect you get when you hand land it. This gave the drone a little lift and I was able to slowly gain altitude and hand land it.

There is a problem with this drone maintaining propulsion, there are many other recorded instances of this behaviour.

Here is another little video of the day, note the weather conditions, the light ripple on the water. If a MM cannot fly in these conditions its not much good to me.

 

[chriscuk]

I can't get the log file to open annoyingly but the videos all show you flying too close to the water. The MM's are known to have issues over water.

 

[Gkinghrn]

I've , in ignorance, flown mine just 3 feet above water on several occasions... No bounce up no down movement ..

I confess I don't really see the point in the bottom sensors as such ... Send to me they can cause as many problems as they can solve , if not more. Going under something close to the ground for instance .. it really needs to have top AND bottom sensors to be more useful

 

[David2111]

I can't get the log file to open annoyingly but the videos all show you flying too close to the water. The MM's are known to have issues over water.

Log file here, issues started at 11 minutes

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

I have been flying for 3 years, two with Mavic Air. Never had issues. The problem was propulsion being lost by MM, DJI say it was related to strong winds, I contest that. Winds were light and essentially no issues until 11 minutes.

 

[maverickRKJ]

On Sunday 12th January MM and me had a bit of flying time around our local river in Armagh Northern Ireland. Weather was good. Wind was around 10mph well within MM capabilities.

View attachment 92256

11 minutes into the flight, the drone dropped 27ft and almost hit the water, it failed to respond to my power inputs on the left stick. The drone was sent back and the flight log also sent to DJI.

DJI responded that the drone was OK.

When asked for their analysis of the flight log it was as follows:

Dear David,

Thank you for your message.

Our Data Analysts have checked the data you provided. Please see their conclusion below:

"1. The aircraft worked under GPS mode and did not respond well to the pilot's command due to the strong wind;

2. Flight Time T=05:16,Relative Height H=13.6 m,Distance to Home Point D=31.8 m,there was no pilot’s input, the aircraft tilted 11.6 degrees rightward to resist the wind,which indicates that there was strong wind affecting the aircraft;

3. T=05:31,H=12.3 m,D=34.1 m,the warning of “High wind velocity. Fly with caution and land in a safe place ASAP” appeared;

4. T=11:00,H=3.7 m,D=23.5 m,the aircraft descended because propulsion was affected by the strong wind;

5. T=12:47,the aircraft landed on ground and no crash incident happened "

If there is anything else we can do for you, please let us know. We will be happy to assist you.

Kind Regards,

Stefan

Customer Service EU
DJI Europe

So, at 5:31 I got a message saying High wind velocity, I honestly cannot remember, but if I did, I did. Apparently during the entire flight, that was the only message I got regarding High Winds.
At 11:00 "the aircraft descended because propulsion was affected by the strong wind"

The MM did not get blown away from me or anywhere else, it simply descended.

That's it case closed.

For me, its the end of me and the MM, I simply cannot put a drone in the air if I can't control it.

There are numerous other posts on this forum and the DJI forum as well citing MM falling from the sky.

I think there is a problem, a serious problem with the control systems of the MM, perhaps lack of power, I don't know but I am very, very glad I still have my Mavic Air.

the more negitive MM flights i read about the more im glad i bought the bigger Mavic Pro , hope it gets bettr for all MM drones

 

[unionglzr]

Log file here, issues started at 11 minutes

DJI Flight Log Viewer | Phantom Help

Upload and view flight logs from your DJI drones

www.phantomhelp.com

I have been flying for 3 years, two with Mavic Air. Never had issues. The problem was propulsion being lost by MM, DJI say it was related to strong winds, I contest that. Winds were light and essentially no issues until 11 minutes.

Not that it will do you any good