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RTH Fail - experienced pilot, never thought it would happen to me :(

sesd97

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Friends, hope you're all flying safe!
Have 4 DJI drones, flow literally hundreds of flights....issue free (till now)!
Yesterday went on an incredible hike and threw out my MP1, flew for 17 minutes with no problems and being only 1,000 ft away from me at most, and at 400' above from home point, I thought time to come home......(thats when the not so fun part started) :

- Lost signal (wow I thought, bad cable maybe?)
- Unplugged and replugged in , with no success
- closed the dji4 go app on my phone, restarted and yes, reconnected! (wow, I was happy)
- pressed controller sticks to take control of drone...NOTHING!, zero effect....oh crap, now I'm in trouble!
- initiated RTH ....(tons of beeping and recognition that she'll RTH)
- ............ahhgggggg, nothing, won't RTH (wow, panicking now.....)
- 2 minutes later, battery low and auto lands....
- I immediately in DJI4 Go app, go to "find my drone" ..... even though it's not the 'exact' location, I find my drone 30 minutes later.... (phew, totally relieved)

....and now, post-mortum please from the experts. I've included all my .dat files, and AirData files...........

thanks in advance for your review :)
 

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Bill combs

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Friends, hope you're all flying safe!
Have 4 DJI drones, flow literally hundreds of flights....issue free (till now)!
Yesterday went on an incredible hike and threw out my MP1, flew for 17 minutes with no problems and being only 1,000 ft away from me at most, and at 400' above from home point, I thought time to come home......(thats when the not so fun part started) :

- Lost signal (wow I thought, bad cable maybe?)
- Unplugged and replugged in , with no success
- closed the dji4 go app on my phone, restarted and yes, reconnected! (wow, I was happy)
- pressed controller sticks to take control of drone...NOTHING!, zero effect....oh crap, now I'm in trouble!
- initiated RTH ....(tons of beeping and recognition that she'll RTH)
- ............ahhgggggg, nothing, won't RTH (wow, panicking now.....)
- 2 minutes later, battery low and auto lands....
- I immediately in DJI4 Go app, go to "find my drone" ..... even though it's not the 'exact' location, I find my drone 30 minutes later.... (phew, totally relieved)

....and now, post-mortum please from the experts. I've included all my .dat files, and AirData files...........

thanks in advance for your review :)
i’m hoping some expert here will help you soon,i have a mpp,m2p,ph4p2.0 and would like to know what happened too.my mpp had an issue with a weak signal a few days ago that shouldn’t have happened since she was only about a 1000’ away with nothing obstructing between me and the bird.
 
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Jet skier

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I just had a similar experience, With my M2P I had to crash my drone into my roof just to get it down as I am in the city. The drone has gone seven months without a hiccup . Sent my drone to DJ I waiting for the results.
 
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bob8755

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That is my worst drone nightmare. It makes me think of all the parents who have to let go of their child as he or she grows up and wants to go places out of our sight. I haven’t encountered a scare like that ... yet. I hope I can keep my wits about me to save myself from my panic.

i’ve read about various bad things that crop up for the first time after a firmware update. So, I’m very reluctant to perform a firmware update. By chance had you done an update recently?
 

Jet skier

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That is my worst drone nightmare. It makes me think of all the parents who have to let go of their child as he or she grows up and wants to go places out of our sight. I haven’t encountered a scare like that ... yet. I hope I can keep my wits about me to save myself from my panic.

i’ve read about various bad things that crop up for the first time after a firmware update. So, I’m very reluctant to perform a firmware update. By chance had you done an update recently?
For me I did have warning signs to somewhat plan for this I had started getting intermittent stick errors that initially I did not think much of and then it started doing more peculiar things and I finally called DJI to ask them what to do. They had me re-calibrate almost everything and I tested it it worked fine for five minutes and then all heck broke loose
 

Jet skier

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For me I did have warning signs to somewhat plan for this I had started getting intermittent stick errors that initially I did not think much of and then it started doing more peculiar things and I finally called DJI to ask them what to do. They had me re-calibrate almost everything and I tested it it worked fine for five minutes and then all heck broke loose
I did have everything updated also
 

sar104

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The reason that the aircraft didn't actually return to the home point, even though it was in failsafe RTH mode, was that the OA system applied the emergency brake. It detected something in its path. That happened a few times previously during the flight too - always when facing approximately SSE.

comp.png
 

sar104

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I think if you had just waited your drone would have returned home. The worse thing to do (IMHO) is to start turning everything off. The drone is programmed (unless altered) to return home if the signal connection is lost.
No - that wasn't the problem. The aircraft was already in failsafe RTH.
 

GerdS

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...
- pressed controller sticks to take control of drone...NOTHING!, zero effect....oh crap, now I'm in trouble!
- initiated RTH ....(tons of beeping and recognition that she'll RTH)
- ............ahhgggggg, nothing, won't RTH (wow, panicking now.....)
I have experienced few remote controller freezes before with my Mavic Pro. Was quite similar to your experience, but my Mavic went into RTH because of signal loss. What action did you define within GO4 for signal loss, landing or RTH?
When I found out that unplugging the phone and restarting GO4 didn't bring back control, I switched off and on again my remote to enforce a cold reboot. That worked and I was finally able to cancel the RTH for manual landing.
- 2 minutes later, battery low and auto lands....
I am used to land before my batteries reach 30%, so there is enough reserve to handle such situations and for a safe RTH. That's also very healthy to the batteries and although they are now 3 years old with almost 140 cycles each they are still in good condition.
 

sesd97

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That is my worst drone nightmare. It makes me think of all the parents who have to let go of their child as he or she grows up and wants to go places out of our sight. I haven’t encountered a scare like that ... yet. I hope I can keep my wits about me to save myself from my panic.

i’ve read about various bad things that crop up for the first time after a firmware update. So, I’m very reluctant to perform a firmware update. By chance had you done an update recently?
Nope, no upgrade in the last few months...I thought my current platform was stable, therefore no necesity to upgrade.
 

sesd97

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The reason that the aircraft didn't actually return to the home point, even though it was in failsafe RTH mode, was that the OA system applied the emergency brake. It detected something in its path. That happened a few times previously during the flight too - always when facing approximately SSE.

View attachment 86840
Agree.....the OA is very touchy when pointing into the sun.
However I thought that once it gets into RTH mode, and no input from the controller, it will "reset" the OA, and then come home....?
My drone (I'm learning now) was kinda stuck, wanted to RTH but couldn't because the OA kept on sensing the sun, and wouldn't 'reset'? It couldn't get itself out of OA failsafe, so it was totally undecided and therefore just stayed in place till low battery and auto-land....

someone asked me if I went into SPORTS mode..... AHHGGG, I'm an idiot, I should have tried that, it would have cancelled the OA, and then MAYBE would have come home ..... what do you think, would it have?

thanks for your help....you are correct, the warning signs were there flying back into the sun!!!

Kinda pilot error, never too old to learn from my mistakes.........:)
 

Meta4

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The reason that the aircraft didn't actually return to the home point, even though it was in failsafe RTH mode, was that the OA system applied the emergency brake. It detected something in its path. That happened a few times previously during the flight too - always when facing approximately SSE.
I looked at the data and was puzzled.
I see the braking to avoid an obstacle message at 20:42.4 but the drone didn't respond to any joystick input at all.
Despite a number of full stick rudder inputs, the yaw angle never moved from 172°.
Despite several full stick throttle inputs, the altitude stayed locked on 400 ft.
Even if braking for an obstacle, rudder and throttle input should have had an effect?

Unfortunately the flyer only gave full forward elevator input so we can't see if reversing would have worked.
I'm also puzzled because the data shows:
MC_PARAM.OAenabled = False
MC_PARAM.rthOAenabled = False
 
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Meta4

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However I thought that once it gets into RTH mode, and no input from the controller, it will "reset" the OA, and then come home....?
If you have Obstacle Avoidance enabled for your flight, it will be on for the return unless you disable OA on RTH in your app settings.

It would be very strange programming to have the drone automatically switch OA off for RTH, when it is most likely to be needed.
 
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Meta4

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i’ve read about various bad things that crop up for the first time after a firmware update. So, I’m very reluctant to perform a firmware update. By chance had you done an update recently?
Despite common myths about it, updating firmware does not cause "various bad things to crop up".
The worst you should expect from a firmware update is that some settings revert to default values and might need to be reset.
I just had a similar experience, With my M2P I had to crash my drone into my roof just to get it down as I am in the city. The drone has gone seven months without a hiccup . Sent my drone to DJ I waiting for the results.
be interested to see the data from that incident.
If the drone would not descend, the obvious suspect is something blocking the downward looking sensors or a malfunction of the VPS sensors.
If you post your flight data, you'll find out a lot more than DJI will tell you and a lot quicker.
 

sar104

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I looked at the data and was puzzled.
I see the braking to avoid an obstacle message at 20:42.4 but the drone didn't respond to any joystick input at all.
Despite a number of full stick rudder inputs, the yaw angle never moved from 172°.
Despite several full stick throttle inputs, the altitude stayed locked on 400 ft.
Even if braking for an obstacle, rudder and throttle input should have had an effect?

Unfortunately the flyer only gave full forward elevator input so we can't see if reversing would have worked.
I'm also puzzled because the data shows:
MC_PARAM.OAenabled = False
MC_PARAM.rthOAenabled = False
The aircraft was ignoring stick inputs while in RTH - I'm not sure why. Almost all the stick inputs at the end of the flight were in RTH mode. However, it did respond to rudder input right at the end of the flight once it switched to P-GPS.

Graph2_1.png

The braking was also recorded in the DAT event stream:

1364.082 : 67977 [L-RC]Emergency break. rc vib!
 

Meta4

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The aircraft was ignoring stick inputs while in RTH - I'm not sure why. Almost all the stick inputs at the end of the flight were in RTH mode.
However, it did respond to rudder input right at the end of the flight once it switched to P-GPS.
I missed that in the last 10 seconds of the data.
But it's very unusual for throttle and rudder inputs to be ignored in RTH.
What was going on there?
 

sar104

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I missed that in the last 10 seconds of the data.
But it's very unusual for throttle and rudder inputs to be ignored in RTH.
What was going on there?
Agreed - rather odd. I've scoured the txt, DAT file and event stream and I cannot see any reason for the behavior. At least some of the ignored stick inputs were while OA_emergBrake = false.
 
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