Wouldn't return to home - even though it said it was doing that

[Shadow2020]

I flew two flights.
On the first, my phone lost communication, which happens occasionally.. and I hit RTH on the controller and my drone returned to home.

I then took off for a second flight. I flew for about 10 minutes and hit RTH on the phone and the drone said it was returning.. but it didn't move..it may have gone to the return height.. but otherwise wouldn't return. I got a low battery warning and started to panic a big because I was over a bridge with traffic and water. I invoked RTH multiple times with the phone and the controller and it kept saying it was doing it.... cancelled.. tried again. I then believe I tried to fly manually (although I was panicking because it said it only had enough battery to return..and I can't exactly remember what was happening..)

Finally I tried to get it to land where it was manually... it responded to that and came down. I could control the camera so I pointed it down. I saw that I would miss the bridge... and it would miss the water by about 2 feet. THis was the most incredible luck. Down it came and it hit a tree or town and finally landed. I was able to find it using the video as a guide. It was on it's side wrapped around some vines, undamaged. I am now afraid to fly it because I can't trust it to return. I am attaching the flight log and would appreciate any help. I am not a novice although I wouldn't consider myself a pro either. I have never had issues except the occasional loss of connection which unnerves me.

Here are both flight logs

 

[Broken Arrow]

Others will have to help with technical data, but from your pic I noticed the Sun was low. Were you flying into the glare, causing the avoidance system to stop your progress?

 

[Shadow2020]

Yes. I didn't realize that was an issue.. but clearly it is. It solves why it wouldn't return home.. and why putting the stick forward didn't cause a response but going down worked fine. If I had known, I would have put it in sport mode and home it would have come. Thank you!!

 

[Meta4]

Yes. I didn't realize that was an issue.. but clearly it is. It solves why it wouldn't return home.. and why putting the stick forward didn't cause a response but going down worked fine. If I had known, I would have put it in sport mode and home it would have come. Thank you!!

That was a close call.
You were on a collision course with the sun and only missed it by 93 million miles.

Reminds me of a near miss I had out in the middle of the Pacific when the crew woke me concerned about a ship bearing down on our boat.
It looked a lot like a ship on a collision course but changing course made no difference.
It turned out to be Venus rising.

 

[Shadow2020]

LOL.

The close call was that when I went down, I was lucky to have not ended up in the road or the water.

 

[Meta4]

I'm not sure what happened to my original reply ... so here it is again

On the first, my phone lost communication, which happens occasionally.. and I hit RTH on the controller and my drone returned to home.

RTH landing accuracy is normally +/- a few feet unless you specifically use the Precision Landing feature that uses optical technology

I flew for about 10 minutes and hit RTH on the phone and the drone said it was returning.. but it didn't move..it may have gone to the return height.. but otherwise wouldn't return. I got a low battery warning and started to panic a big because I was over a bridge with traffic and water. I invoked RTH multiple times with the phone and the controller and it kept saying it was doing it.... cancelled.. tried again. I then believe I tried to fly manually (although I was panicking because it said it only had enough battery to return..and I can't exactly remember what was happening..)

As usual the mystery is solved by looking at the recorded flight data.
AT 13:32.8 you initiated RTH.
The drone turned to face home and climbed toward RTH height.
It was reporting the whole time: Backing up to avoid obstacle
It reached RTH height (197 ft) but kept climbing to avoid the obstacle until it reached your Max Altitude limit at 394 ft.

The obstacle was almost certainly a bright and low sun and the Mavic couldn't see a way to get past it.
This happens occasionally.
The mavic would have flown anywhere you directed it, except straight towards the sun.
Flying 10 degrees in either direction would have been fine or disabling the obstacle avoidance would have solved the problem.
Your screen display should have shown you obstacle avoidance info (?)

 

[Shadow2020]

They are on the Mavic forum. I originally posted here by mistake.

 

[gnirtS]

Flying directly into the sun. Obstacle avoidance.

However i would question why, if you noticed RTH wasn't work you simply didnt fly it back manually? If something isnt working then just take over manually. Although features like RTH are nice they shouldnt be relied on. They can, and do, fail.

 

[Shadow2020]

I tried... I was on the other end of that bridge...directly forward. So when I tried to have it come toward me, it wouldn't move. I assumed it was not responding to me at all. When I moved the other stick, it went down and I assumed that was the only thing it would let me do. I was surprised at that. If I had my wits about me, I might have tried to move sideways or backwards or to turn on sports mode. However, it was blaring that it was running out of battery and I was worried to have it high above the bridge... and thought I needed to do the only thing it would let me... bring it down.

In retrospect of course, the fact that it wouldn't fly toward me wasn't a sign it wouldn't fly at all... in the moment, I just didn't realize that. I am otherwise very adept at flying it manually.

 

[Shadow2020]

any comments by anyone on the first flight? Why did it give me a communication error with loss of the feed to my cell phone. The drone still responded to the RTH from the controller.. in that case, I was in no position to fly manually....

 

[Meta4]

any comments by anyone on the first flight? Why did it give me a communication error with loss of the feed to my cell phone. The drone still responded to the RTH from the controller.. in that case, I was in no position to fly manually....

The flight data doesn't give much to go with.
The data just stops at 1:53 with the drone 1950 feet out and in stable flight.
It was high enough that terrain would not have blocked signal.
I suspect that you were not able to initiate RTH at all (it's kind of a problem when signal has been lost) and that the drone came home just as it is programmed to when signal is lost.

 

[BossBob]

any comments by anyone on the first flight? Why did it give me a communication error with loss of the feed to my cell phone. The drone still responded to the RTH from the controller.. in that case, I was in no position to fly manually....

Even with loss of signal to your cell phone you still had full control of your drone through the remote control. Your cell phone as a viewing and information device is really just a luxury that you should be able to fly without. As for depending on RTH, yet another luxury that you should not be depending on. Try learning to fly without both, it can be much more satisfying!

 

[4wd]

The phone might only just be coping with the demanding app,
My Samsung S5 is similar and will start to struggle after a few minutes unless I turn off the video cache.
It's also useful to restart just before setting out so there are minimal background processes.
Also the thin cable into the side doesn't work as well as a good data cable in the bottom port.

 

[Meta4]

Even with loss of signal to your cell phone you still had full control of your drone through the remote control. Your cell phone as a viewing and information device is really just a luxury that you should be able to fly without.

He only said that he lost signal, not that the app crashed.
With loss of signal, you have no ability to control the drone.

As for depending on RTH, yet another luxury that you should not be depending on.

Sometimes failsafe RTH is all you have left.
DJI in their wisdom hardwired the loss of signal behaviour into their drones.
But you are able to switch disable that in the settings if you don't want to depend on it.

 

[thewinelake]

Droneless newbie here, but is the consensus that, for the second flight, you should have turned on sports mode (to disable collision avoidance) and then flown back manually, or would RTH work ok then?

 

[colinfowler]

If RTH is not bringing you home, switch to sport (disabling OA) and fly back manually. Check RC distance reading to confirm its decreasing.

 

[thewinelake]

So you can’t have RTH in sports mode? Probably too dangerous!

 

[Meta4]

So you can’t have RTH in sports mode. Probably too dangerous!

RTH is a separate flight mode.
You can't RTH in P-GPS, Atti or Sport modes.
When you initiate RTH, the drone goes to RTH mode.
In this incident, it would have been manually flyable in Sport Mode or any other mode would have worked if obstacle avoidance was switched off, or it could have been flown back manually if the course was altered to avoid facing into the sun.

 

[colinfowler]

So you can’t have RTH in sports mode? Probably too dangerous!

Aircraft cannot return to the Home Point when the GPS signal is weak or unavailable.
Aircraft will stop ascending and immediately return to the Home Point if you move the left stick in the aircraft reaches 20 meters (65 feet) altitudes or beyond during Failsafe.
The aircraft cannot avoid obstruction during Failsafe RTH if Forward Vision System is disabled. It is important to set a suitable Failsafe altitude before each ight. Launch the DJI GO 4 app, enter “Camera” and tap to set the Failsafe Altitude.
User cannot control the aircraft while it is ascending to its failsafe altitude. However, user can press RTH button to exit the ascent and regain control.

 

[BossBob]

He only said that he lost signal, not that the app crashed.
With loss of signal, you have no ability to control the drone.

Sometimes failsafe RTH is all you have left.
DJI in their wisdom hardwired the loss of signal behaviour into their drones.
But you are able to switch disable that in the settings if you don't want to depend on it.

First flight his cell phone disconnected from the rc, nothing mentioned about the app crashing. Makes no difference, as he was able to RTH on the button if he knew where his drone was he’d have been able to fly home manually.
Second flight he hit RTH to come home. No mention of any disconnect at all. If he’d been looking at the screen he’d have seen the sun blotting out his vision via the camera, it would be obvious if manually flying to turn to one side or the other to get the sun out of view and then fly a more circuitous route to his chosen landing spot.