Disaster on first Litchi Mission!

[ukracer]

Hi All,

I decided (based on what I have read) to move from DJI Go 4 to Litchi and thought lets try it in a large open field to see what happens - SO GLAD I DID!

Capture.PNG

This is the moment just prior to all hell breaking loose and the final conclusion where the drone ended upside down in the field (thankfully only mud damage to the props).

What is concerning is, at no point did the drone try to RTH and I have no idea why not, long press on C2 or Home button on the controller had no effect.

Can anybody shed some light on what I did wrong or why this occurred?

 

[AlecW]

Wow your gimbal and camera seemed unsteady and way off for the entire flight. Is it normally like that?

 

[ukracer]

No the Gimbal and Camera were fine from home through wp1, 2 & 3 an
d then just prior to the video clip went a awry!

Sent from my STV100-4 using PhantomPilots mobile app

 

[DocDiggler]

Seems your gimbal mode is in FPV not Follow mode
Was the compass and IMU checked before the flight
All sensors clean?


Sent from my iPad using PhantomPilots

 

[DocDiggler]

DJI app was not running in the back?


Sent from my iPad using PhantomPilots

 

[tevek]

Have you had a look at the data from something like Healthy Drones? It should give you some idea of what the state of your signal, controls and battery were doing. I had a similar experience with the gimbal simply dropping and the drone behaving weirdly, managed to land it, no error messages but changed the battery and it was fine after that. At the time of my occurrence, there were other threads of similar behaviour leading towards a battery issue, so I cycled the suspect battery as I had been simply topping it up each time and it never happened again.

 

[ukracer]

By cycled the battery does that mean 'run it right down, rather than top up after each flight?

sent from BlackBerry Priv

 

[tevek]

By cycled the battery does that mean 'run it right down, rather than top up after each flight?

sent from BlackBerry Priv

After each flight I recharge it to 50% and turn it off, charge it fully before each flight and so on. I realised looking at my charge cycles that they didn't match the number of times I had actually charged the batteries as it wasn't counting little top ups as a cycle. Not sure if it is related to your incident but the gimbal fault and wobbly flight I experienced, either coincidentally or otherwise lined up with a number of similar threads on this forum and I did some checking and found I was doing it wrong. You need to look at your flight data for a more definitive answer to see what was going on at the time. I use HD all the time and it's easy to sync your litchi flight to the site and check it out.

 

[ukracer]

Ok had another 'trial' today and this one seemed to be a bit better (well at least it didn't crash).

Prior to the flight, using DJI Assistant, I reset P4 to factory defaults, at the site of the flight, I calibrated the compass.

The drone completed the mission, and hovered at the last waypoint, until I brought it down to earth.

This is a short clip from the mission

Having uploaded the logs to HealthDrones, I am alarmed to see the signal between the drone and the controller is 'POOR' and could be why, halfway through this short mission, I was alerted with a caution and on checking the notifications I see this ..

Failed to upload the mission (reason: Execution of this process has timed out).

Flight time: 01m 06s
Altitude: 92.2 ft
Home Distance: 469 ft

This occurred yesterday moments before all hell broke loose so when I go the alert today, my heart missed more than 1 beat!

This is signal log from HealthyDrones (open in new tab)

And this is the GPS log (open in new tab)

Weather permitting (I am in the UK).

I will try another test next weekend.

 

[Jayfdee]

Whenever I have had a failed to load message,which is now never since I changed to an ipad, it would not even start the mission. I have never seen this message once a mission had started.
I always take off manually and check all the stick movements and home point etc, then select mission and load, and then press go. I have over 100 litchi missions, and never a problem.
I get poor signal reported on Healthy Drones if I am using a screen recorder as well. I have tested this by running the same mission twice, with and without a screen recorder. I get full signal when the screen recorder is off, and poor signal when on, maybe worth checking.

 

[Jayfdee]

PS your 2nd video looks good, and like a typical Litchi mission.

 

[ukracer]

Hmm interesting Jayfdee. I don't think Litchi on Android (Samsung) galaxy tab has a screen recorder function. If it does its well hidden.

sent from BlackBerry Priv

 

[Jayfdee]

Hmm interesting Jayfdee. I don't think Litchi on Android (Samsung) galaxy tab has a screen recorder function. If it does its well hidden.

sent from BlackBerry Priv

No not an inbuilt one,(Litchi on IOS does), but a stand alone app , I think it was AZ recorder on android that I used that had this effect.

 

[Samuraiz]

To add to what Jafdee said, I personally use Litchi 99% of the time. I only use GO when I want to do calibrations or adjust DJI only parameters (Battery issues IMU issues etc) Before flying either a mission, or a FPV flight I always allow the craft to hover approximately 30 feet (10 meter) in place for at least 30 seconds to insure that it is completely stable. I personally won't commit to a flight with less than 14 GPS sats. I then apply stick input to insure that all controls are properly functional. After a minute if all is well I either load and execute a mission or manually fly. I have never received a failure to load mission. warning. The mission is stored on your device and uploaded to the craft. I use an IPAD 4 mini. Remember you can cancel a mission at any time by moving the switch from P to sport or Atti If I saw my craft doing what your craft had done in the first video I would have aborted the mission and manually flown it back.

 

[hunterxero]

Had exactly the "gimbal tremors" issue on a DJI Go flight. Never found a root cause, although I was pitching the camera down so that it was almost at 90 degrees. In that case I used RTH and everything worked out. Just pressing the RTH button on the controller is not sufficient. You need to push, release, then push and hold to get RTH to engage. As others have said, the other option is to move the flight mode switch from P to S. Then bring the bird back using line of sight.

Another thing I have done when having a shortage of GPS satellites is pushing the bird up to 400 ft. Sometimes that improves the GPS count and the radio signal.

Finally, I strongly suggest regular IMU calibrations.