Hi All,

Today I decided to check weather my Mavic Air also uses different procedure for Fail-Safe RTH than for other RTH modes.
The answer is yes it does. It retracks the remembered track and does not take course direct to home point.
As I think about that for a bit longer - it's quite smart as retracking your flight path is possibly the best way te get into contact again.

Here's small video from that test:


Br, Pawel.

Interesting. I don’t remember reading about this. Could you post a screenshot of your RTH settings please?

Certainly an interesting one to note. I guess they assume the "RC lost" scenario wont need it to RTH completely, as if you are flying a long way out but a short way back, then the RTH failsafe might not make it home. I guess in that instance, if it gets to a point where it can't make a direct flight back, it will assume low battery RTH and fly directly home? One to test for the brave ;)

Interesting, might be a strategy to avoid obstacles. But it would not be a wise strategy in case of low battery RTH as Cameleon has pointed out above.

Wachtberger Posted at 2018-2-21 09:11
Interesting, might be a strategy to avoid obstacles. But it would not be a wise strategy in case of low battery RTH as Cameleon has pointed out above.

That’s exactly what it’s for, it’s the very same system as in inspire2 and P4Pro.

I'm not brave enough to check but I hope that during Failsafe RTH if battery low level is triggered Mavic itself (assuming that there is still no connection with RC) switch to Low Battery RTH and from that point go directly towards home point.

I realized how important is to set up RTH behavior and altitude before every flight depending on what we are going to do. It is easily to imagine that FailSafe RTH when triggered can lead to lost of aircraft if parameters are not set up correctly (ie it looses signal and tries to follow saved path with higher altitude and it hits a tree from below...)

I think that DJI is not explaining that clearly enough in the manual.

Br, Pawel.

pawel_g Posted at 2018-2-21 10:27
I'm not brave enough to check but I hope that during Failsafe RTH if battery low level is triggered Mavic itself (assuming that there is still no connection with RC) switch to Low Battery RTH and from that point go directly towards home point.

I realized how important is to set up RTH behavior and altitude before every flight depending on what we are going to do. It is easily to imagine that FailSafe RTH when triggered can lead to lost of aircraft if parameters are not set up correctly (ie it looses signal and tries to follow saved path with higher altitude and it hits a tree from below...)

I believe it does, IE: 1. "Smart RTH" flies directly to the Home Point based on preset altitude. 2. Failsafe RTH returns to Home Point flying back along flight route (FS RTH Overrides "Smart RTH"). 3. Low Battery RTH flies directly back to Home Point (Overrides FS RTH & Smart RTH). 4. Critical Battery Warning (Activates immediate landing.) Overrides all of the above. Seems to be the same for all the DJI Drones.

I wasn't aware of this feature either, but  I at first thought it a great idea.  What I was surprised to see is that the quad gained altitude before following the original track back.  What if you'd flown OUT by passing beneath some tree branches?  Following that path home, but at a higher altitude could be bad.  I wish that feature would follow the exact same flight course AND ALTITUDE on return.

StanfordWebbie Posted at 2018-2-21 10:44
I wasn't aware of this feature either, but  I at first thought it a great idea.  What I was surprised to see is that the quad gained altitude before following the original track back.  What if you'd flown OUT by passing beneath some tree branches?  Following that path home, but at a higher altitude could be bad.  I wish that feature would follow the exact same flight course AND ALTITUDE on return.

Yes, especially that you cannot set RTH altitude to nothing lower than 20m.

Br, Pawel

StanfordWebbie Posted at 2018-2-21 10:44
I wasn't aware of this feature either, but  I at first thought it a great idea.  What I was surprised to see is that the quad gained altitude before following the original track back.  What if you'd flown OUT by passing beneath some tree branches?  Following that path home, but at a higher altitude could be bad.  I wish that feature would follow the exact same flight course AND ALTITUDE on return.

There is some responsibility remaining with the pilot at all times, even with the great Tesla's, isn't it? You can disable RTH altitude but then all is in your hands naturally.

hallmark007 Posted at 2018-2-21 10:05
That’s exactly what it’s for, it’s the very same system as in inspire2 and P4Pro.

Extremely smart then, thank you for confirming!

QuadKid Posted at 2018-2-21 10:41
I believe it does, IE: 1. "Smart RTH" flies directly to the Home Point based on preset altitude. 2. Failsafe RTH returns to Home Point flying back along flight route (FS RTH Overrides "Smart RTH"). 3. Low Battery RTH flies directly back to Home Point (Overrides FS RTH & Smart RTH). 4. Critical Battery Warning (Activates immediate landing.) Overrides all of the above. Seems to be the same for all the DJI Drones.

Is anyone opposed to me getting this tattooed on the palm of my hand?

Jeff

Nice! Pawal i guess u liked mine so much u made your own video.. lol post mine yesterday ..  this comes out today! Beauty of the internet.  Check out "Mike sarni" yt

https://youtu.be/mEJDqzxGUJg
I do have alot of informative videos also...like how to return home faster in rth mode....and how to pick wifi setting on mavic air..

First, you flew out downwind.  Always a bad idea.  Second, you flew out in sport mode.  Not good either, as it uses even more power.  At least you thought to put it down before letting it go in the drink.  

Huh?? ^^^^^

$gambino$ Posted at 2018-2-21 16:43
Nice! Pawal i guess u liked mine so much u made your own video.. lol post mine yesterday ..  this comes out today! Beauty of the internet.  Check out "Mike sarni" yt

No I did not see your video as this is not so easy to see any video about Mavic Air that is posted on YT. I don't recall seeing it here.

I was inspired by some posts here and wanted to simply make some "laboratory" test for myself (low altitude, low distance) to be sure how it works. That's why I did not make this video public, only showed it here as my personal test.

Not going to teach anyone via my videos as I'm total newbie to drone world.

br, Pawel

Hi there, it is true that the drone will retrace the original flight route back when the fail-safe RTH engaged for Mavic Air. When failsafe RTH is engaged, users can try to adjust the antennas position and see if the signal will regain.

Thanks, I know that part of manual, but I always need do see how this works in real world.
Could you please confirm (as I'm not so brave to make such test) that if during Failsafe RTH low battery condition is met aircraft switches to Low Battery RTH and flies shortest way to home point abandoning the retrack procedure?

br, Pawel.

Thanks for point that out... guess I overlooked this one too. Also thanks for the perfect summary QuadKid. Guess this clarifies the RTH once and for all.

It is very fascinating how much tech goes into these quads

Interesting vid - thanks for sharing.

Cameleon Posted at 2018-2-21 08:27
Certainly an interesting one to note. I guess they assume the "RC lost" scenario wont need it to RTH completely, as if you are flying a long way out but a short way back, then the RTH failsafe might not make it home. I guess in that instance, if it gets to a point where it can't make a direct flight back, it will assume low battery RTH and fly directly home? One to test for the brave ;)

The manual has some new clarifications, if not reconnected within 60 seconds, it will fly straight back.

https://forum.dji.com/thread-139795-1-1.html

Thanks for showing us your test. I was too afraid to try disconnecting while in flight.

$gambino$ Posted at 2018-2-22 15:40
It is very fascinating how much tech goes into these quads

It is absolutely awesome - i was flying the other day, and an older lady wandered over to talk to me, ask about the drone; "My husband used to fly RC aircraft - is it plastic, or balsa wood?" - i really had to try hard to stifle the massive laugh that almost errupted!  "It's basically a flying computer" i said, and then spent a few minutes showing her many of the features. "Wow it really is like a flying computer!" she says at the end   


Anyway, thanks for highlighting this RTH info - much appreciated!

pawel_g Posted at 2018-2-21 10:27
I'm not brave enough to check but I hope that during Failsafe RTH if battery low level is triggered Mavic itself (assuming that there is still no connection with RC) switch to Low Battery RTH and from that point go directly towards home point.

I realized how important is to set up RTH behavior and altitude before every flight depending on what we are going to do. It is easily to imagine that FailSafe RTH when triggered can lead to lost of aircraft if parameters are not set up correctly (ie it looses signal and tries to follow saved path with higher altitude and it hits a tree from below...)

GPS positioning is a little "drifty". That's why precision landing requires the drone to initially gain altitude without moving horizontally. A snapshot of the landing area is saved to better position to the exact take-off point. This isn't happening For the entire flight. Even if the return height was the same, the zig-zag pattern can't be completely trusted to match exactly. I've been lucky and haven't had any disconnects, but I'd be running towards the drone, holding the remote in the air if I did.

Talking about RTH what would happen if in RTH program APAS is turned on and it would have to fly to the direct bright sun (APAS does not work in very bright or low light) would it stop, o what would happen?

Reading latest version of Mavic Air manual - it says that Fail Safe RTH will follow recorded track only for 60 seconds. If no contact with RC is made within those 60 seconds aircraft abandons recorded track and starts return in straight line to home point (exactly the same as Low Battery and Smart RTH)

Br, Pawel.

Supose, while the MA is on its returning pad and are in these 60 seconds under a tree, and the straight home starting up, the MA will rising up to min 20 meters or to the additude that you have set in you settings..I think, you can pick them up under the tree.

Anyone knows how to dissable this feature?
In case i want to use the old school RTH....

Not trying to be facetious, but how many people have read the manual?