RTH Tragedy

[drickbrinkman]

Hello, first post and new to drones. I'm sure this is all my in doing, but I do have a question. I used to fly RC planes a lot, but it's been a while.

Yesterday, I was showing my new Mavic Pro to friend. I flew it around the front yard at less than 20' and all was fine until I was going to show him how it could fly itself back to home. I pushed the button and the drone immediately rocketed straight up into a tree canopy and then proceeded to do it a couple more times before dropping to the concrete driveway (naturally). I broke the camera gimbal mount (actually the anti-vibration plate) and ripped the flat circuit cable in half. Video still works, but of course I get motor overload messages about the gimbal. I watched a bunch of repair videos and I think I can fix this myself for about $40. At least I don't seem to need a full $300 camera setup or even the metallic thread video cable. I've worked on mechanical wristwatches before, so I think I can delicately handle this surgery.

My question is about overhead obstacle avoidance. Does it have any ability to do that?

BTW, I won't be flying in the yard anymore until I know every aspect of the software features. Before the crash, I also got messages about heavy interference and experienced blocky video to my phone even at very close range. Is that likely from the phone's WiFi being turned on during flying?

Thanks for reading.

I had the same experience, rocketing straight up into the tree canopy and crashing when I wanted to try the auto landing.

It relates to the RTH, Return to Home. Once activated the Mavic flies up to a predetermined altitude (I think the default is about 90 feet), then flies to it's GPS takeoff spot and lands. The idea is that it goes to a height that will avoid all obstacles and fly back to it's take off spot.

You can't disable RTH, but you can adjust the altitude. However, in a tree canopy it's not a practical feature. And once RTH is initiated you lose the ability to cancel it until it's at it's landing location. I called DJI to find this out.

RTH gets initiated three ways: 1. You pressed the button on the control screen and confirmed 2. The Mavic has determined it only has enough power to get back to it's take off spot. 3. The Mavic loses touch with the controller.

Since flying around the forest is what I want to do I have learned three things:

1. Which button on the screen is RTH and don't press it! ;-) And it's next to the auto-land button.
2. I monitor battery level and make sure I manually return before it gets down to half.
3. If I am going to fly above the tree canopy, then I take off from the one spot in my driveway that has open sky. That way RTH could work. However, that is only when flying above the trees and not within the trees.

If you are flying within the trees, you are probably keeping the Mavic in line of site anyway, so you are not going to lose touch with the controller. Then it's just a matter of not pressing the RTH (which also requires a confirmation) and monitoring battery life.

 

[colinfowler]

You can't disable RTH, but you can adjust the altitude. However, in a tree canopy it's not a practical feature. And once RTH is initiated you lose the ability to cancel it until it's at it's landing location. I called DJI to find this out.

You can change in settings to RTH hover or land

 

[Mike4884]

Drickbrinkman I am certain you can stop rth... I always just hit the pause button

 

[JeffCharger]

Took it all back apart and checked the gimbal cable. Redid it and ordered a couple of spares since they seem to be quite prone to damage. Turns out that one of the ribbon cables going to the main computer board might not have been fully plugged into its connector. After reassembling it, minus the upper shell and GPS module, it powered up, ran its gimbal test and suddenly had video again. It also stopped claiming that there was no SD card. Of course there was no GPS, but that was expected. After putting it all back together, it works! Running Go 4 version 4.1.10, I did some test flying and had one disconnect. I reinstalled 4.1.18 and it worked much better than originally. Video was smooth and not seriously lagging. I did have one disconnect though. The quad hovered and waited for a reconnect which I was able to effect. The controller was showing connected, but the aircraft knew better and so did the app (I tend to think the problem is the app) because when flying without a phone attached, everything stays connected fine. I do like flying with the app, even though I'm old school and used to having only VLOS. Took a few snapshots and captured some video. The snapshots look good on the phone, but I haven't pulled the video from the drone yet.

What I've learned: Read the manual, don't try features if you don't know exactly what is supposed to happen, the gimbal parts (cable, rubber hangers, drop hook, vibration board) are easily damaged but can be fixed inexpensively, people with the no video and no SD card complaint might have a minor problem that doesn't involve replacing the main boards, removing and reinstalling the phone app might help, many other things.

Great to hear that you were able to repair the ribbon cable. I will keep you in mind if I break mine!