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P3A - Mistaken Landing Then Disconnect

Discussion in 'Pro/Adv Discussion' started by bpatrick, Jul 22, 2016.

  1. bpatrick

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    So here's the situation...

    I have the P3A. I was flying the drone around and all was good, but then I started to get a bit a weak signal - the drone was about 1500 feet away with some tree interference. I tapped the "Land" icon by mistake in the DJI Go app, I meant to tap the "Return to Home" icon.

    The landing had been initiated. When I realized what I had done, I immediately tapped the "Red X" to cancel the Landing operation. However, at this point, I received a messaage that the command "Timed Out". Then, the app showed that I no longer had any connection to the drone.

    My assumption was that the drone would realize that it had lost it's connection to my remote control, cancel the landing operation (since my cancel command failed due to the time out), and Auto-Return Home.

    Well... I was certainly wrong. I waited a couple of minutes expecting to either see the drone returning, and/or have the connection re-established. Neither of those things happened, so I quickly jumped in the car and drove to the last known point on the map that app reported location of the drone.

    Sure enough, when I arrived at that location, my drone had safely landed (by sheer luck). If it had landed 10 feet away, it would've been in a tree or water [​IMG]

    I immediately checked the settings in DJI Go app, and it set to Auto-Return Home when a disconnection occurs.

    Obviously, I would like to avoid a potential disaster in the future, and obviously it was my fault for accidentally tapping the "Land" button, but I'm wondering why/how the drone actually landed while disconnected.

    Shouldn't it have returned home?
     
  2. msinger

    Approved Vendor

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    Please upload your TXT flight log here and post a link back here so we can review your flight in more detail.
     
  3. bpatrick

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    Please forgive me, I've never obtained the flight logs before. I tried following the instructions provided here: Professional - Downloading flight data using a Mac.

    However, I'm not having any luck. All I see on my Mac is a mount for "NO NAME" which allows me to navigate into the DCIM folder and get images/video. Using the Disk Utility, again all I see in the Left column is Macintosh HD and NO NAME. I'm not sure what I'm doing wrong, but I don't see any logs anywhere. I've followed the steps provided in the link above, and chose to enter flight data mode from the DJI GO App, so I'm not sure what's happening here...
     
  4. bpatrick

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    Additionally, in the app if I tap "Flight Data Mode. Restart aircraft to exit." It takes me to a screen where "Overall Status" has a red icon. If I tap that - it says "Data Recorder Errors"
     
  5. msinger

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    Please follow the instructions in my link above.
     
  6. BigAl07

    BigAl07 Moderator
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    It seems like I've seen similar behavior before from other flyers. When the "land sequence" is initiated I "think" the aircraft will complete that completely void of the controller unless it gets a specific set of instructions otherwise.

    It's like this (and I'm going out on a limb here because I have never looked into the code for the Phantom FC)....


    Land and Return To Home are hard-coded processes within the aircraft. It's not a function of the controller except the controller can execute the command for each one. Once the process it started the true automation of the Flight Controller (FC) goes into play and they will attempt to complete the assigned task until it's complete, or it's instructed not to (by the controller) or until a condition is disruptive (tree, water, powerline, building etc) preventing the completion.

    Since it sounds like you lost connection to the aircraft nothing you did could "affect" the flight and it continued until Terr Firma.
     
  7. bpatrick

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    #7 bpatrick, Jul 22, 2016
    Last edited: Jul 22, 2016
  8. bpatrick

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    Thanks for the info, and based on what you're saying, that sounds exactly like what happened. The problem is that is obviously very dangerous. It doesn't really make sense to me that under any other circumstances the craft would return home. Seems like this is a bug in the logic. If I have the option enabled in settings to always return home when disconnected from the controller, the craft should do just that...

    Frustrating
     
  9. BigAl07

    BigAl07 Moderator
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    Keep in mind that Auto Land is a very good and needed fail-safe. It will be almost impossible to account for every situation but the Flight Controller on these AC are almost amazing.
     
  10. Rommel

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    I guess you need to look at it from a different POV. The AC has certain automatic functions that will kick in unless you direct it otherwise. You gave it a command and it followed that command.

    If you had a situation where it RTH but you wanted it to land elsewhere, for whatever reason, but the craft simply ignored you, you'd be much more frustrated.

    Don't take this wrong, we all make mistakes, but this seems to be user error.

    Tony
     
  11. bpatrick

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    Yes, I accept full responsibility for it being user error in that I accidentally tapped "Land".

    However, If I had not lost connectivity, I would've easily been able to cancel that command. Additionally, look at it this way: If I had instructed the drone to fly away from me, and it disconnected, the drone would return home. So, I don't see how it is any different.

    Scenario 1) Instruct the drone to fly away from me, disconnection, return home.
    Scenario 2) Instruct the drone to land, disconnection, land anyway??

    Certainly seems like a logic flaw to me. Perhaps it is my software engineering mind getting in the way...
     
  12. bpatrick

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    Perhaps they need to add another configuration setting called: "Really Return Home Upon Disconnection" ;)
     
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  13. Not A Speck Of Cereal

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    Respectfully, it is quite a bit different:

    Look at it this way: lets say that someone is flying and their RC starts wigging out. Seeing this, they initiate a landing procedure immediately and see it begin that, then the RC gives out. They see the AC stop the landing procedure that they requested and then fly off to do something else (the RTH procedure). We could very well have a user complaining "I told it to land, but then it did something completely different!!"

    If by "instructed the drone to fly away from me", you mean simply pushing the stick forward, then what would happen on disconnect would be the same thing as letting go of the stick: it would stop going forward and just hover. After the time-out, it would perform the programmed failsafe procedure (which could be RTH).

    But you had already given it instructions to land. It wasn't just hovering. So to me, it is different.
     
  14. bpatrick

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    Certainly you could argue that the 2 scenarios are different, and that's fine.

    However, I still think the AC should *always* return home when it gets disconnect from the controller. I personally cannot think of a scenario where I would want it to not return home.

    Having said that, I understand other people, perhaps, have a different view/preference, which is I why I think they should add another configuration setting, which says "Really, no matter what, return home if AC disconnects from controller". The user can choose to turn that setting on/off. I *thought* the configuration setting that already exists was clear enough.
     
  15. Not A Speck Of Cereal

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    I certainly wouldn't object to a "No matter what, return home if AC disconnects from controller" setting.

    In response to this: "I personally cannot think of a scenario where I would want it to not return home", here is one: People using Litchi to fly missions point out that a valuable feature of that app is that it will continue to fly the mission, even if the remote signal is lost. This is not the GO app, but note that the mission is no long APP specific if the remote goes down — the instructions are now all in the bird. I suspect that's because the Litchi app is developed with the DJI SDK with the AC's onboard controller/log.

    Another scenario: a person might instruct it to land because they are not sure of their RTH procedure is programmed to have enough clearance on the return trip to hit an obstacle on the way back. That clearance is programmable and people are advised to check that setting each time they fly, but do they?

    What if I previously programmed in 80M for an RTH altitude, but during a firmware upgrade (or for any other reason), the setting was defaulted back to 30M and I didn't notice it? In that case, "I told it to land, but it performed an RTH anyway when my remote signal was lost" might not end happy.

    I am not certain that my viewpoint is any more correct that yours. But I can imagine that when designers and engineers at DJI sit in a room and ponder default and user programmable procedures, they take these kind of scenarios into consideration.

    Chris
     
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  16. bpatrick

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    With regard to Litchi - Obviously the craft knows what is a real time flight, vs what is a pre-planned flight. Because you're correct, when running a Litchi mission, the craft does not return home when it disconnect from the RC.

    So, in the end I think we're in agreement, it just needs to be another configuration setting.
     
  17. Numone

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    RTH does it for me. For the first time the other day I lost signal. Screen went dark and probably for 20 or 30 secs (which seems like an hour, with my heart in my mouth!) and nothing...
    Then it sprang back to life and it was returning home with the message "cruising at xxxx feet returning to home." Frankly I was amazed. It is amazing!
     
  18. fastfed

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    only time I would ever use auto land feature would be a long distance flight and I cannot get home due to battery restraints. I would look for a safe and secure location lower it as low as I could before losing connection and hit auto land.

    and drive to the location.

    For return to home , why not just use the big button on the remote? I never use the app.
     
  19. ufo88

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    This is a definitely a user error- Let's move on and don't waste time. Case closed.......
     
  20. Numone

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    Thanks Judge...

    The OP realises that, but we try to be helpful, supporting here, not judgemental and disparaging.