What happened? (litchi VR)

[Henfri]

Hello,

I just flew my first litchi VR mission and it did not go well...

I climbed to 50m and put my phone into my VR Goggles after switching to 'immersive' mode. Unfortunately, the USB cable came loose. At this point, the Mavic Pro started to descent.
But it did not just descent, but also fly left and aft. I had the feeling, I could *slow* this movement, but not stop it. The Mavic crashed into my house. This was not the end; The motors did not stop spinning, but continued. What can be the reason for that?
I understand, that in immersive mode, the direction that the head (aka phone) points in, gives the direction of the drone. But I do not think that this explains the behaviour...

Fortunately, only the props did not survive. Everything else is ok. But I'd like to learn from it (and maybe others can, too).



Greetings,
Hendrik

 

[brett8883]

Hello,

I just flew my first litchi VR mission and it did not go well...

I climbed to 50m and put my phone into my VR Goggles after switching to 'immersive' mode. Unfortunately, the USB cable came loose. At this point, the Mavic Pro started to descent.
But it did not just descent, but also fly left and aft. I had the feeling, I could *slow* this movement, but not stop it. The Mavic crashed into my house. This was not the end; The motors did not stop spinning, but continued. What can be the reason for that?
I understand, that in immersive mode, the direction that the head (aka phone) points in, gives the direction of the drone. But I do not think that this explains the behaviour...

Fortunately, only the props did not survive. Everything else is ok. But I'd like to learn from it (and maybe others can, too).



Greetings,
Hendrik

I have a possible explanation. When in immersive mode the drone is really in joystick mode so it is being controlled by the virtual joysticks of the app but they are just hidden. When you move your head the app recognizes this input and applies yaw to that direction. There have been reports that when in joystick mode and the app is removed that the drone can sometimes remain in joystick mode. Now Litchi immersive mode isn’t designed to control the altitude stick but that functionality is built into joystick mode. When the app was removed it might have remained in joystick mode and somehow thought it received those commands. This is also why you might not have been able to control it because there is a joystick limiter where actual stick inputs are dampened.

I think you would have been better off switching to sport mode in that situation to kick it out of joystick mode and back into manual flight when things went south. If you post your flight record though we’ll be able to get to the bottom of it

 

[bliksem]

I used Litchi once.... never again.
I created a mission in Litchi and it flew the drone perfectly and came in to land.... and then everything went sideways or backwards. For no reason the drone accelerated backwards and up into a tree at about 60' from a height of about 20', this happened in an instant. I switched to Sport to override but it was too late.
Needles to say that was the last time I used Litchi, never again thank you.

 

[joeruby]

I used Litchi once.... never again.
I created a mission in Litchi and it flew the drone perfectly and came in to land.... and then everything went sideways or backwards. For no reason the drone accelerated backwards and up into a tree at about 60' from a height of about 20', this happened in an instant. I switched to Sport to override but it was too late.
Needles to say that was the last time I used Litchi, never again thank you.

I have over 600 air miles on my P3P with most of those miles using Litchi, and a large percentage of those miles as Litchi missions. I started using Litchi because DJI Go didn't have waypoints. Litchi Mission Hub and Litchi Virtual Mission can now calculate and program the required altitude at each waypoint. Litchi Virtual Mission can even fly (simulate fly) the mission before you fly it for real. I don't need anything smarter that that!

You might want to determine what actually caused your accident. Maybe you had "Return to Home" as part of the mission, and the aircraft was simply raising to the "go-home" height when it hit the tree. Anyway I find Litchi extremely reliable.

Joe
KC7GHT

 

[bliksem]

I have over 600 air miles on my P3P with most of those miles using Litchi, and a large percentage of those miles as Litchi missions. I started using Litchi because DJI Go didn't have waypoints. Litchi Mission Hub and Litchi Virtual Mission can now calculate and program the required altitude at each waypoint. Litchi Virtual Mission can even fly (simulate fly) the mission before you fly it for real. I don't need anything smarter that that!

You might want to determine what actually caused your accident. Maybe you had "Return to Home" as part of the mission, and the aircraft was simply raising to the "go-home" height when it hit the tree. Anyway I find Litchi extremely reliable.

Joe
KC7GHT

Jep I had RTH set at the end of the mission.
The MP completed the mission and executed a RTH at the "safe" RTH altitude of 90' that I had set, then proceeded to land. At 20' it started climbing and backing up, I did flip to Sport mode and hit Up but I was too late to clear the tree that was about 60' behind RTH. Someone did analyze the log file and could not explain the anomaly, but put it down to a Litchi glitch - i.e. no cover from DJI. The log file shows the MP was backing up at about 25mph before impact. No other insight came out of the log file, hence I have zero faith in Litchi.

 

[brett8883]

Jep I had RTH set at the end of the mission.
The MP completed the mission and executed a RTH at the "safe" RTH altitude of 90' that I had set, then proceeded to land. At 20' it started climbing and backing up, I did flip to Sport mode and hit Up but I was too late to clear the tree that was about 60' behind RTH. Someone did analyze the log file and could not explain the anomaly, but put it down to a Litchi glitch - i.e. no cover from DJI. The log file shows the MP was backing up at about 25mph before impact. No other insight came out of the log file, hence I have zero faith in Litchi.

Litchi uses the DJI SDK and does not control the drone in RTH. RTH is handled internally by the drone and Litchi saves csv logs to your device so I think DJI pulled one over on ya hate to say. Litchi can’t make the drone do something the DJI firmware doesn’t allow it to do and isn’t capable of giving commands to the drone in RTH or sport mode.

 

[joeruby]

Jep I had RTH set at the end of the mission.
The MP completed the mission and executed a RTH at the "safe" RTH altitude of 90' that I had set, then proceeded to land. At 20' it started climbing and backing up, I did flip to Sport mode and hit Up but I was too late to clear the tree that was about 60' behind RTH. Someone did analyze the log file and could not explain the anomaly, but put it down to a Litchi glitch - i.e. no cover from DJI. The log file shows the MP was backing up at about 25mph before impact. No other insight came out of the log file, hence I have zero faith in Litchi.

Looks like Litchi completed it's mission properly, and your MP entered a DJI return to home. Then the failure occurred. At that time it was completely out of Litchi hands. Did your Mavic loose GPS signal under the tree? Anyway study any data you can get from the MP. Based on what you just told us, it is not Litchi's fault.
Joe
KC7GHT