Forced auto-land crash...

[rtw07]

So... my Mavic decided to go rogue today and auto-land into a forest. I was flying off a local river getting some photos a couple thousand feet away from my location. No issues with connectivity or video feed. I turned it around to bring it back and noticed that it had been drifting higher, up around 300 feet.

I gave left stick down and it automatically went into a forced landing mode. I attempted to cancel the auto-land on screen but the red X was greyed out and wouldn't respond. Full left stick up wouldn't stop the landing. I was able to maneuver horizontally but not vertically. I realized it wasn't going to make it back to me without landing in the water so I got it over some trees before it finally went down and crashed.

Luckily I was able to recover it from the woods... It actually held up quite well. Broken prop but the gimbal seems to be alright. Thoughts? I have insurance with State Farm but this seems to be a technical issue that I hope DJI will own up to. VPS issues I assume.

DAT: Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-03-25_16-21-32.DAT
txt. log: Phantom Log Viewer - PhantomHelp.com

 

[Cyberpower678]

You uploaded the wrong DAT file. I can't open it. The DAT is a large file in the 100s of MB.

 

[msinger]

When you were trying to descend with the throttle stick in the full down position, the VPS was showing your Mavic was 0.2 meters from the ground. That cause the forced landing mode to be initiated. It's a common problem we're seeing when people are flying over water.

 

[rtw07]

When you were trying to descend with the throttle stick in the full down position, the VPS was showing your Mavic was 0.2 meters from the ground. That cause the forced landing mode to be initiated. It's a common problem we're seeing when people are flying over water.

Shouldn't stick up cancel the forced landing?

 

[rtw07]

You uploaded the wrong DAT file. I can't open it. The DAT is a large file in the 100s of MB.

Try this one instead... Dropbox - DJI_ASSISTANT_EXPORT_FILE_2017-03-25_16-21-32.DAT

Thanks

 

[msinger]

Shouldn't stick up cancel the forced landing?

I haven't tried it since I'm not able to reproduce a forced landing when not near the ground. In some other threads, people were saying a stick up does not cancel forced landing mode when using the current Mavic firmware. A few other people said it could be cancelled by switching to sport mode. I don't think any of those people were testing those cancellation methods when high up in the sky (just when close to the ground).

The best advice I can give you is to turn off VPS when flying over water. Or never move the throttle to the full down position when flying over water. Either will prevent forced landing mode from being accidentally initiated.

 

[Egika]

Without having looked at the file: he said he recovered it from the woods. To me that means it was not above water...??

 

[msinger]

Without having looked at the file: he said he recovered it from the woods. To me that means it was not above water...??

Take a look at the file and you'll see the Mavic was flying over water at the time.

 

[MacIak]

Loads of people seem to have this issue lately with the introduction of firmware .4 and/or .5
Not just above water but randomly way up in the air.
Dji blames it mostly on faulty vps units, i have my doubts.
I stopped firmware upgrades at .200 cause every firmware imports gremlins.

 

[Egika]

Take a look at the file and you'll see the Mavic was flying over water at the time.

Ah, ok

 

[rtw07]

I don't believe water was the issue here. Doesn't the bottom-facing VPS system have a short vertical range? I was over 300 ft altitude when I attempted to lower the Mavic and it automatically when into auto-land.

 

[rtw07]

And maybe the bigger problem here is that I wasn't able to stop the auto-landing command. With previous firmware versions, you could cancel it with upward stick movement.

 

[msinger]

Doesn't the bottom-facing VPS system have a short vertical range?

Yes, but something was within its detection range (e.g. sunlight shining off the surface of the water).

 

[rydfree]

Switching to sport mode should cancel any flight mode it was currently in and transfer control back to the operator . Not saying it will always work but it should be the first thing to try when the Mavic is not responding to control inputs .

 

[msinger]

Switching to sport mode should cancel any mode flight mode it was currently in and transfer control back to the operator .

Have you ever confirmed this while your Mavic was in forced landing mode and not near the ground?

 

[rydfree]

Have you ever confirmed this while your Mavic was in forced landing mode and not near the ground?

No that's why I used the term "should" . I have tried it in about every other instance though and if that ever happens it will be the 1st thing I shall try

 

[LawFlyer]

When you were trying to descend with the throttle stick in the full down position, the VPS was showing your Mavic was 0.2 meters from the ground. That cause the forced landing mode to be initiated. It's a common problem we're seeing when people are flying over water.

As a newer flyer, I admit I'm still learning but I wanted to understand this comment (at first, I had no idea what you meant).....

But let me see if I got this -- normally, when you bring the Mavic home to land and are descending close to the ground, at some point the Mavic sees the ground and then slows its descent (same as when doing a RTH -- it drops quickly when high in the sky and then slows as it approaches the ground). Eventually the Mavic will hover a few feet above the ground. In order to land, you bring the left stick down fully and hold it, which then brings the Mavic down to a soft landing.

Is that what you're calling a "forced landing" - i.e., by holding the throttle stick down, you are "forcing" it to land rather than allowing it to continue hovering? I think that's probably the idea.

I guess it makes sense that IF a Mavic is high in the air, and IF something is causing it to falsely think it's just a few feet off the ground (like sunlight reflecting off water and blinding the downward facing cameras), then pulling down on the throttle would start a slow "forced landing" (because the Mavic thinks it's just a few feet above the ground, so that's how it reacts to the downward throttle).

But I didn't realize that a forced landing can't be stopped, and I also thought the downward ultrasonic sensors measured height above the ground, not the cameras, so it's surprising that sunlight would affect them and cause a false ground proximity reading.

Hmmm....these little bugs are really frustrating, but it seems critical to be aware of them so you can respond appropriately when it happens. So, what exactly IS the correct response? Flip into Sport mode? Seems like from 300 feet AGL, there would be plenty of time to try that....or a few other things.

 

[BorisTheSpider]

In .500 firmware (the latest) the only way to cancel an automatic landing is to switch to sport mode.

It's dumb and bad design to make the highly intuitive "left stick up" not cancel it, I have no idea why DJI did that and I hope they change it back soon.

 

[no sweat]

I was hoping that DJI had stopped using the owners for testing their next firmware updates. I've got a Phantom 3A that has a 7 second video delay since I updated the firmware last fall. I've read on the forum how changing the cable on the gimbal, changing tablets, etc., etc. would correct it. I've used a Ipad and a Samsung Tab 2. They both controlled the drone great before the updated firmware. Now they both have the 7 second video delay. It appears DJI doesn't want to address the real problem - DJI's firmware updates.
I love my drone but the firmware issues are so disappointing.
I was going to order a Mavik from Drone World as soon as they sent me word that they had them in stock. Now, reading that Mavik is having issues that seems to me should have been taken care of months ago I'll have to rethink the purchase.

 

[LawFlyer]

In .500 firmware (the latest) the only way to cancel an automatic landing is to switch to sport mode.

It's dumb and bad design to make the highly intuitive "left stick up" not cancel it, I have no idea why DJI did that and I hope they change it back soon.

Good to know and VERY TRUE -- there is no reason why left stick up shouldn't stop the landing. Odd that with so many settings in the remote, there isn't a way to manually change this.

Also, as the weather gets warmer I'm going to be doing a lot more flying from our boat, and the takeoff/landing area on the rear deck is pretty small. Good to know that once I start that "forced landing" procedure, I am committed to the landing spot. I mistakenly thought that if the landing starts to go wrong, I could throttle up and attempt a do-over. I guess not!