Correct response to flight software freezing?

NickU · May 19, 2017

First off, if you're flying DJI Go in Tripod mode, then the aircraft won't hover if the app freezes, it'll simply carry on flying and doing whatever you tell it to do with your stick inputs. Generally the only time the aircraft will hover is if the app tells it to if it loses control, or you've programmed it to do so when the Remote command signal is lost.

Ignoring that for now...

Option 1
unplug the cord, replug the cord, everything works. You have control, so fly home manually - why waste time trying to engage the follow me mode?

Option 2
No different to option 1.

Don't confuse the app losing video signal with the app crashing - they're different.

App loses video signal
You still have control via the RC sticks. Generally the video downlink will come back up in a second or so and you can carry on, the App controls still appear to work (i.e. you can elect menu options etc). In this case the home point is still where it took off from and isn't reset - the app has never been lost or restarted.

App crashes
The App freezes up on you or just closes down, so you've no response from the app controls or it's just dumped you back at the tablet home page. You still have full control of the ac using the RC sticks, just no comfort blanket video feed and no on-screen buttons to press

! At this point the home point is still set at the take-off point. So, you can either use the RTH button on the RC, or fly back to you manually if needed. If it's safe to try and you want to, you can try to restart the App. If it restarts, then fly back to you using manual control. if it doesn't, then still fly back under manual control. If at any point you have restarted the App for any reason, then check where the home point is showing on the map. If the Aircraft and home point are one & the same, then DON'T press the RTH as it will simply land in place (unless that's what you want!).

So, back to your scenario....

I'm out flying the ac over a lake having taken off from dry land. After a good flight and with 30% left on the battery, when I'm out over the lake, the App crashes and dumps me back at the iPad home screen. If I'm close to home and can easily see the ac to determine flight path/orientation then I'll just fly it back to me using the RC sticks only.

If I'm further out and it's harder to see the orientation of the ac, then I might try to restart the app just to get the video feed back up. Thing here is not to get hung up on restarting the app - you can get so engrossed trying to work out how to get it back up n running that you lose track of time and run out of battery power. However, you should have set your Smart RTH options - that would pick up the remaining power levels and distance to home point and would initiate the smart RTH to go home when it figures the battery level is only enough to get back home (which is still set at take off point remember - you have't got the app running again yet

)

In all cases, unless you have lost the RC command link, you can always fly manually using the sticks. If you lose the RC command link, then the aircraft will begin the RTH to its last recorded take-off/home point.

If you are running a semi autonomous program and the app crashes, then you can always toggle to ATTI mode to regain control. If that doesn't work, then last ditch attempt is to deliberately shutdown the RC to try to initiate the RTH due to signal loss. If that doesn't work... call your local ATC to report the fly-away!

It's late Friday night... hope that lot makes sense!!!

Once again... unless you've lost RC signal, you always have control using the sticks. If you're running an intelligent flight mode and don't have control... switch to ATTI, then you should have control.

Florida Drone Supply · May 19, 2017

NickU said:
Best thing to do is go somewhere with good all-round visibility where you can play safely, then try out the various scenarios to see what happens - hitting rth at various distances, dumping the app, restarting the app, pulling the usb cable, putting the cable back in, toggling ATTI mode to get control back from automation, power down RC & so on - that way you get used to what happens when the smelly stuff hits the fan *before* it happens in real life - eases some of the panic attack and "WTF!!!" moments

It also teaches you keep cool, fly with sticks only, and not to always rely on the rth function because it doesn't alway do what you'd expect it to (eg when the app has crashed & restarted & reset the home point!).

Great advice.

JoePGM · May 20, 2017

NickU said:
First off, if you're flying DJI Go in Tripod mode, then the aircraft won't hover if the app freezes, it'll simply carry on flying and doing whatever you tell it to do with your stick inputs. Generally the only time the aircraft will hover is if the app tells it to if it loses control, or you've programmed it to do so when the Remote command signal is lost.

I agree and will suggest hit the "stop" button on your RC immediately if your apps freeze or crashed during any autopilot program so let it hover and stay. Suppose your I2 is somewhere locate in a mid-air that is "safe" (e.g. not over the rail track where are train is coming....). Gain the time to restart the apps and fly home immediately once your system restored. Don't rely on RTH unless there are no-choice....

JoePGM · May 20, 2017

I have a Trackimo installed on my Yuneec and I will install it to my I2, it is not the best (highest frequency update is 1min), but at least gain more safety device to track my I2 position even lost video signal, or the worst case, find the crashing site..... (touch wood)

I have never try any crazy flight and so all my flight are constantly with smooth video signal and control.

Ftolino · May 20, 2017

Mine lost connection twice now good thing precise landing was on or it would've crashed into a wall,cemetery monument. It didn't trigger return to home it just landed an that's not how I have it setup both times it was 10' off the ground an within 50' of me . By the time it happened there's nothing you can do but watch it land an shut off . Little scary

NickU · May 20, 2017

Ftolino - If it's within 50' then that's why it landed - if it's within 65ft (20m) of the RC, then it lands in place.

JoePGM, I presume you mean the little pause button on the RH side of the RC unit (the one next to the photo shutter button). By all means press it... but if nothing happens, then try toggling the flight mode switch to ATTI and back - that's the most sure-fire way of getting back control. ATTI turns off the GPS hold, and that in turns immediately disconnects any in-flight program or intelligent flight mode settings that're running at that point. (If you're like me, using the pause button means you might hit the shutter button instead

)

The Editor · May 20, 2017

NickU said:
Ftolino - If it's within 50' then that's why it landed - if it's within 65ft (20m) of the RC, then it lands in place.

JoePGM, I presume you mean the little pause button on the RH side of the RC unit (the one next to the photo shutter button). By all means press it... but if nothing happens, then try toggling the flight mode switch to ATTI and back - that's the most sure-fire way of getting back control. ATTI turns off the GPS hold, and that in turns immediately disconnects any in-flight program or intelligent flight mode settings that're running at that point. (If you're like me, using the pause button means you might hit the shutter button instead )

Just be mindful this will not ALWAYS instantly release the aircraft.
I have personally suffered a lock out when I had an app crash.
I can catagorically say that there was no stick response immediately after the app crash. Atti had no affect in my scenario and after some trouser filling seconds, I regained logical thought and pulled the USB lead - control was immediately returned.
This is why I mention about USB protocol release above. It is not alway instantaneous and whilst (in theory) full RC control should be maintained I can say from experience it isn't!
I have reported this to DJI R&D but unfortunately (and probably thankfully) I have been unable to replicate the issue.

NickU · May 20, 2017

Good to know about that Editor. I'll remeber that if it ever happens. So far, the ATTI toggle's always worked for me.

Mikemal · May 20, 2017

NickU said:
Yes, it's purely a visual aid. The RC is the really important thing that controls the aircraft.

If an App freezes, then several things can happen:

Nothing! You're cool, just restart the app and carry on. Watch out though - check where your home point is set to as the app may reset it to the current aircraft position when it restarts - you may need to manually reset the home point to the RC's location instead.

if flying under pilot control, then the RTH options MAY kick in or not. It depends on what has been lost App only, App & RC Signal - the RTH options will normally only activate if the Remote controller signal is lost for several seconds - that isn't the same as the video downlink being lost, or app control being lost. Getting home is easy... you carry on flying with the RC & sticks, and manually fly the aircraft home... of course you're a good law abiding person and are operating within line of sight at all times, so flying home isn't hard! If you haven't restarted the app yet (ie changed the Home point), then you could manually activate RTH - but you need to know what it will do - rth/hover/land!

If the RC signal is lost for several seconds, then RTH should automatically activate - so the aircraft will either ascend to the set RTH height then fly home, or hover until it gets the RC signal back, or it will land if within a certain distance of the RC - depends what you set in the RTH options. When the RC is back in signal range you can cancel the RTH and fly manually again.

Your tablet freezes up and needs restarting. Don't panic! Simply hover the aircraft in a safe spot, or land if safe to do so, and restart the app. If the App starts again and doesn't show the live video feed, then try unplugging & re-inserting the cable, it may have a bad connection. So long as the RC is still in range, you can fly manually regardless of the state of the App.

If an autonomous mission or automation flight has been uploaded to the aircraft, then the aircraft normally carries on doing what it was programmed to do - depends what response was set in the mission programming - it could be carry-on & return at end of mission, carry on & hover at end of mission, abort mission & return home, abort mission and hover... it does what you told it to do at the start of the mission. If you have RC control, but no app control and want to abort the mission and take over manually, then you can toggle the flight mode switch from P-GPS/S-GPS to ATTI to cancel the automation. Be careful in ATTI mode as the aircraft will drift with the wind... so you may want to toggle straight back to P-GPS or Sport to regain GPS position hold. The automation shouldn't restart and you should have manual control back. See 2 above for further help!

Don't panic and start hitting every button around - that's when things go wrong! Where things go wrong too is where you restart the app, think "Phew", then as you're a bag of nerves, hit the manual RTH button, and the aircraft either lands immediately or flies of somewhere! Then you think WTF!! oh no! Of course home is now not where it was (the app has reset it!)

That's why it's important to try the options out and find out what happens first! Also, don't use the RTH buttons as a lazy way to come home - they may not do what you thought they'd do!

That's the best response I've ever read (the topic comes up a lot) - good job, and thanks for posting!

Shayd · May 20, 2017

JoePGM said:
would like to know how actually the I2 will behave if the Go apps freeze or crashed during flight? will it stop and hover in the position, will it RTH immediately (suppose the I2 will store the home point or GPS data for emergency use) or just land immediately?

The DJI GO app crashed on my Pixel XL, Lost no control and was able to bring it closer before I tapped on the app

RocketBrew · May 20, 2017

The GPS chipset will work even without any cellular service activated. The cellular model is just required to get the GPS chip included.

Synonomau5 said:
I'm also wondering if I have the iPad w/ GPS and Cellular, does the GPS work if the Cellular is on 'airplane mode'?
.

Mixchief · May 20, 2017

Today I had a total disconnect, app grayed out and apparently record disabled, second time this happens to me, however this time I was maybe just 500 feet away, instead of panic, I exercised the joysticks first noticed craft responded normally and proceeded to return home manually. Don't feel confortable doing it automatic after a disconnect after a few seconds the iPad re connected and I flew back hovered for a while recording my neighbor and his daughter and allowed the battery to drain, which was my main reason for that particular flight. So the moral of the story is, if the app crashes, just fly the old fashioned way BLIND. Oh and the record never popped out, the recording is all there.

Synonomau5 · May 20, 2017

RocketBrew said:
The GPS chipset will work even without any cellular service activated. The cellular model is just required to get the GPS chip included.

Thank you, good info!