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COMMAND TIMEOUT: Phantom would not land, move, or turn off.
984 3 2020-10-21
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Jantzen
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United States
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Hey all, I'm hoping someone can shed light on some of the events that occured during today's flight. The aircraft is a stock Phantom 4 Pro, purchased in March 2017.

I was out getting footage for a friend that's having me document the progress of a huge house he's building and things had been pretty routine on the first flight. Then, things started to get weird when I tookoff a second time using my backup battery.

Like always, I instructed the aircraft to precisely record the home point. We were in somewhat of a rush because we were on a lunch break. So, as it was taking off, I tried to switch to tripod mode and received this error: Cannot Enter Current Flight Mode – Takeoff Failed

I dismissed the error as nothing because I figured the aircraft was still recording the home point. It was hovering right in front of me so I knew that takeoff did not actually fail. It took longer than usual, but I was eventually able to switch over to tripod mode.

All flying in this situation was inherently at a low altitude and non-aggressive... The house only has the basement foundation poured at this point. Conditions were pretty ideal, except for some intermittent wind.

A few minutes in, the remote control somehow lost connection with the aircraft despite it being roughly 100 feet away with a clear line of site. This triggered the return-to-home sequence at 35% battery and the drone started ascending to 1,000 feet. The video feed was restored within 2 seconds but I never regained control of the aircraft. I tried to cancel the return-to-home sequence but it kept saying: Command Timeout

When the drone finally made its way to the home point, I went to manually land+catch it like I always do (people love seeing it). However, it just sat there hovering at ~10 feet above the cul de sac... just out of arm's reach. The app said the area was unsafe for landing. I cleared the space and tried to land it using the app, but, again: Command Timeout

I killed the app and restarted the remote multiple times but nothing worked. I had crystal clear video but couldn't control the drone.

It was COMPLETELY UNRESPONSIVE. It wouldn't move forward, backward, left, right, up, down, upside down... nothing. It wouldn't land and I couldn't reach it. I had my wife hold the controller while I moved my truck underneath it so I could grab it... DO NOT DO THIS. The drone's obstacle avoidance kicked in, causing it to fly aggressively forward in the direction of a 50-thousand dollar truck and million dollar house. Thankfully, it stopped about a foot away from hitting the truck and was somehow a couple feet lower than it was before.

I ran over to it and was able to jump up and snatch it out of the sky. Obviously, the drone did not like that much either. I could not get the battery to turn off manually. I had to physically remove it with the motors spinning at full tilt. Thankfully, I only lost one finger.

I'm hesitant to take it out again because I believe this could have ended much, much worse. I am looking for answers about what happened and why. I'm not sure if this is normal, but the flight log was split into two. I've posted them below. Thank you for reading and any insight you can provide.

Flight Log - Part 1: https://www.phantomhelp.com/logviewer/4LJX0ERIZWDMZ4C9KT01/
Flight Log - Part 2: https://www.phantomhelp.com/logviewer/9HXJ5A554SR940QWPPEO/
2020-10-21
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DJI Stephen
DJI team
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Hello there Jantzen. I am sorry for the trouble this has caused and thank you for reaching out. May we know what mobile device you are using please? If you are receiving a command timeout error on the DJI Go 4 application, this means that the DJI Phantom 4 Pro can not receive and react to your commands. Kindly please uninstall and reinstall the DJI Go 4 application and also kindly please try to use a different USB cable as well. Thank you.
2020-10-21
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Labroides
Core User of DJI
Flight distance : 9991457 ft
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Australia
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Like always, I instructed the aircraft to precisely record the home point.
Why?
The Phantom records its homepoint automatically without you having to do anything.

I tried to switch to tripod mode and received this error: Cannot Enter Current Flight Mode – Takeoff Failed
There was some sort of minor glitch that hung up the control of the drone.
It's not clear why.

This triggered the return-to-home sequence at 35% battery and the drone started ascending to 1,000 feet.
Why do you have your RTH height set to 1000 ft?
There are several reasons why that's not a smart thing to do.

The video feed was restored within 2 seconds but I never regained control of the aircraft. I tried to cancel the return-to-home sequence but it kept saying: Command Timeout
What did you do to try cancelling RTH?
The simplest way to cancel RTH (or any automated flight mode) is to flick the Flight Mode switch out of P-GPS and back.
That probably would have sorted things out for you.


2020-10-21
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JJB*
Core User of DJI
Flight distance : 12225059 ft
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Netherlands
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Hi Jantzen,

I combined your 2 logs into 1 file.

Did you try 2 times to grab your drone standing on your truck?  2 times driving under your drone?

As said by the DJI moderator ; command timed out so no RC connection upwards to your drone.Seen in your log, all the RC inputs had no effect. Even switching the RC on/off did not help.
It hovered at 2.9 VPS height all the time as the landing spot wasn`t safe to land.

I think beacuse of compass disturbance it flew away from position, in the log at the end a compass error. Don`t think it will move away when the bottom sensor detects something ; your hand. Normally it will only pull up, not move away from position.
Last record only 1% batt left, so if you had waited just a bit longer craft was coming down; easier catch...

Sorry about your finger, did you really lost it ?

cheers
JJB


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2020-10-24
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