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Lost control of Mavic pro - twice

Cloud Bustet

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Joined
Jan 20, 2019
Messages
3
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4
Problem? See below

Was unit in a crash? Yes

What have you tried so far? see below

What device are you using ( iphone , ipad, Samsung , etc)? iPhone 7 plus iOS 12.1

What firmware are you running ( aircraft, remote controller)? controller 01.04.0500
AC version is unknown according to app. I do not want to turn on the AC.
When I launched everything was normal. The message stated version is up to date. I calibrated the compass.

What Go app version are you using?4.3.12

Any modification? (if so what) none

Did you change anything or install any apps? (if so what) No

Do you have a video or pictures of the problem? (if so post link) No see below



I have been flying this AC since Jan 2017 and have not had this problem. I was flying on 4/9/17 legally in a forest preserve area to capture retake video for an aerial imaging business that I was close to turning live this week.
I am a 107 not flying today as a 107.

I have flown in this area last year and a couple of times this year without incident. Last year I captured video of the roof of a 30' long 18' high picnic structure which was deteriorating. I capture this video for editing practice and wanted to retake this to make a comparison of a year' weather on the roof for my web site.

The batteries were fully charged, and I recalibrated the compass prior to launch. GPS mode was secured at launch. I took several photos and some test footage to get exposure, composition correct. I was flying in tripod mode. When I launched I heard the message RTH recorded. I did not activate RTH and the drone only launched about 7' in the air.

The building height being 18 feet via drone measurement using camera angle at 90 deg. I shot several passes of the roof at two different heights the max was 50'. I had no problems. (FYI when I got home and imported them the location was correct on photos and videos but the time of the videos were around 10AM ish and the photos showed the correct time of 3:pM ish. Not sure why? The photos were taken before and after the video scenes so it was not a clock being reset.

On the same battery I wanted to capture flying through this open structure which I did. Unfortunately I neglected to hit record for any of the remaining actions. I thought I did.

The trip through the building was at 10' height and I was about 6 feet behind the drone. When I flew thru the building I decided to try recording a backing out of the building video. So I flew about 20' into the building and was in the process of backing out when I lost total control. I heard battery warning RTH activated message. It started to fly erratically and I could not control it. I tried bringing it to the ground & (dual stick down) but nothing I did helped. FYI the flight starting point (RTH) was about 10' away directly in front of the position of the AC when it acted up. I was on low battery 20% but not sure why I could not put it on the ground. Looking at the app data RTH ht was set to zero.

As I fought the sticks the AC started bouncing off the outer roof edge and eventually came down hard and shut off.

The FRT Rt rotor lost about a third of each blade and one of the LR lost a third and the other side had damage. So they were chewed up.

I wanted to see if the motors still worked so I put in a new battery and took it out into the open and started it. An RTH activation message was again heard and it went up 7' and started again flying very erratically in spite of the blade damage. I could move it around somewhat but the best I could do was dual stick and I brought it to the ground eventually but it would not shut off. I did not want to put my hand in to press the battery button and I just watched it for a few seconds hoping it would turn off, but it jumped into the air and started flying irregularly over a large area. After a brief time it stayed in a position and so I turned off the controller and shut down the GO app hoping that it would land. It just kept hovering moving in an out and around an 8' area. It slowly descended as the battery drained. Finally landing with a dead battery.

I planned on using this drone as a backup to a new drone that I was planning on purchasing for this business. It has taken over a year and a half with learning Lightroom, photoshop video editing and building a web site to get this business off the ground. Last week I got the domain name and state registration. Now I have little confidence in this AC because of the damage.

I have to assume interference had a major role but I am not certain nor do I understand. Can somebody look at the logs etc to see what happened. I DL'd the log and text files. I am not sure why there are three .txt files for this day. I only had two flights. Two DAT files are present.

I hooked up the controller to the iPhone and I am not sure if the settings accurately reflect all the settings. Meaning does it save everything to view without being connected to the AC? On the controller tonight RTH ht was 0 ft and the interference panel showed a red line across the top. I have never looked at this before.

Looking at my flight records in the GO 4 app has me concerned how it is recording data. For example. Top distance listed is 8,823 with a date of 12/3/2019, Max takeoff altitude 862.6' 25/9/2018. I am assuming that it is referring to Christmas day. I did not fly on Christmas. The flight list shows three flights today. The first 1046 ft for 20 minutes @76', the second 166 ft @ 2' for 1 minute and the last 6 ft, zero ft for 1 minute.

Any help would be appreciated.


Thanks
Rich
 

Attachments

  • 2019-04-09_15-00-59_FLY098.txt
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  • 2019-04-09_15-26-03_FLY100.txt
    522.3 KB · Views: 1
  • DJIFlightRecord_2019-04-09_[15-03-00].txt
    2.5 MB · Views: 1
  • DJIFlightRecord_2019-04-09_[15-26-17].txt
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  • DJIFlightRecord_2019-04-09_[15-26-40].txt
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That's an interesting flight. An unusual feature is a systematic offset between the IMU and GPS, especially north/south (0.015 m/s):

69001

Discrepancies of this magnitude usually indicate a compass problem but that's not what was going on here - yaw was correct which is why most of the flight seemed fine.

At the end of the flight the problem was a combination of lack of GPS, RTH some poor choices of stick input, and possibly exacerbated by the IMU offset noted above:

69002

RTH was triggered when SMART_BATTERY_battery dropped below SMART_BATTERY_goHomeBattery, at 1125 seconds. The backwards excursion that caused the crash was due to your elevator input at 1129 seconds however, to which the aircraft responded properly:

69005
 

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