Is this actually what the problem was? Did my drone go down because it was flying directly beneath my feet under a bridge?

[nowtleft]

I was stood on a bridge and lost all control as it passed underneath. No warning, nothing. It felt like the object avoidance went in reverse sucking the drone into the rocks.
DJI FPV.
DJI is investigating but this thought struck me as the only reason for the accident.
Thoughts please

 

[Yorkshire_Pud]

Simple loss of connection anywhere should not cause a crash. Loss of connection must happen thousands of time daily and only in a very few cases is there a subsequent crash.
What happens as a consequence of the loss of connection and your subsequent actions, if any, is an entirely different matter.

Your best bet is to provide a description of the flight and the txt flight log for the flight. That, combined with a description of the flight and area may provide clues to what is likely to have subsequently happened.

You will need to connect a phone, with the fly app installed on it, to the goggles to get the flight logs and it may take a while to get the logs downloaded. Then go to DJI Flight Log Viewer | Phantom Help to get instructions on how to get the logs off the phone, up load the relevant log to that site and then post the resulting URL here.

Regarding description, include speed as it started to go under the bridge, dimensions of the bridge, its material, what's under the bridge, the drone's settings etc......etc. etc. etc.

 

[edcMavicPilots]

Several things could have happened. Your RTH was not set to hover so lost signal told the drone to rise to whatever height it was set at, crashing into the underside of the bridge. Maybe you kept moving the controls after losing video. Magnetic interference from the bridge caused erratic behavior. There are probably a lot more but I have seen people experience all of those.

 

[nowtleft]

Simple loss of connection anywhere should not cause a crash. Loss of connection must happen thousands of time daily and only in a very few cases is there a subsequent crash.
What happens as a consequence of the loss of connection and your subsequent actions, if any, is an entirely different matter.

Your best bet is to provide a description of the flight and the txt flight log for the flight. That, combined with a description of the flight and area may provide clues to what is likely to have subsequently happened.

You will need to connect a phone, with the fly app installed on it, to the goggles to get the flight logs and it may take a while to get the logs downloaded. Then go to DJI Flight Log Viewer | Phantom Help to get instructions on how to get the logs off the phone, up load the relevant log to that site and then post the resulting URL here.

Regarding description, include speed as it started to go under the bridge, dimensions of the bridge, its material, what's under the bridge, the drone's settings etc......etc. etc. etc.

Hi, thanks. I have done all you suggest and have the video from the goggles. I am waiting t8 hear from DJI but the bridge span was large and speed about 2 mph. It was as though the drone was magnetically attracted to the rock!

 

[nowtleft]

Hi, thanks. I have done all you suggest and have the video from the goggles. I am waiting t8 hear from DJI but the bridge span was large and speed about 2 mph. It was as though the drone was magnetically attracted to the rock!

The future is green not orange on TikTok

A beautiful day and a great subject. So why did the drone stop responding 8 foot below me? I was super slow and careful. Its under investigation.

vm.tiktok.com

this is a link to the video on tiktok.

 

[FLDave]

My guess is that it hit a side wall.
I've watched several YouTube videos about flying under a bridge so I could decide if I wanted to or no. One thing is of utmost importance: maintain visual contact as GPS contact will likely be lost, and that's when looking into the bridge tunnel. Some suggested partial trial entries, It takes practice and is risky.

 

[MAvic_South_Oz]

Then go to DJI Flight Log Viewer | Phantom Help to get instructions on how to get the logs off the phone, up load the relevant log to that site and then post the resulting URL here.

Post #2, until that happens . . .

 

[Yorkshire_Pud]

It has just occurred to me that the actual name of the the .txt and or .DAT flight logs may not follow the usual DJI format. 'Certainly' one of them doesn't but the folder structure (where the logs are stored) is normal and it is evident what the files are from their extensions (.txt or .DAT) if nothing else.
I will check later in the morning (just woke to go to the loo) lol

 

[Rich QR]

I was stood on a bridge and lost all control as it passed underneath. No warning, nothing. It felt like the object avoidance went in reverse sucking the drone into the rocks.
DJI FPV.
DJI is investigating but this thought struck me as the only reason for the accident.
Thoughts please

How's the GPS signal under the bridge? How far above the underlying ground was the drone? Or was it perchance over a body of water? How much experience do you have flying in ATTI mode?

My crazy guess would be that you lost GPS signal under the bridge, and the downward-looking vision sensors were unable to maintain stability, so the drone went into ATTI mode. In ATTI mode, if you get close to a solid object beside or above the drone, the vortices will feel like they're sucking the drone into the solid object.

 

[nowtleft]

How's the GPS signal under the bridge? How far above the underlying ground was the drone? Or was it perchance over a body of water? How much experience do you have flying in ATTI mode?

My crazy guess would be that you lost GPS signal under the bridge, and the downward-looking vision sensors were unable to maintain stability, so the drone went into ATTI mode. In ATTI mode, if you get close to a solid object beside or above the drone, the vortices will feel like they're sucking the drone into the solid object.

Thanks. If the above is what happened wouldn’t it be common knowledge to not fly under bridges particularly when going under yourself? Surely if the connections good 4 miles away it should cope 15’ below the controller?
I’m not an expert in any mode but surely what I was asking the drone to do wasn’t so tricky?

 

[AnzacJack]

Thanks. If the above is what happened wouldn’t it be common knowledge to not fly under bridges particularly when going under yourself? Surely if the connections good 4 miles away it should cope 15’ below the controller?
I’m not an expert in any mode but surely what I was asking the drone to do wasn’t so tricky?

Mmmm
I thought it was pretty well common knowledge not to fly slowly under a structure that will inhibit gps signal, unless you are prepared to fly manual.
Unfortunately, when flying in anything other than manual, you are not actually flying the craft. Your just telling the flight controller what you want it to do for you. If that flight controller losses one of its primary inputs (gps, IMU or compass)its unable to maintain control.
Imagine if you were running through a maze and someone threw sand in your eyes

 

[Rich QR]

Thanks. If the above is what happened wouldn’t it be common knowledge to not fly under bridges particularly when going under yourself? Surely if the connections good 4 miles away it should cope 15’ below the controller?
I’m not an expert in any mode but surely what I was asking the drone to do wasn’t so tricky?

I thought it was (somewhat) common knowledge to either fly where you have a GPS signal, or where the downward vision sensors can stabilize your flight. If you don't do that, you'll have to deal with ATTI mode, and if you're in close quarters and not expecting ATTI mode, it will probably not end well.

If you search for the term "ATTI" in the crash and flyaway assistance board on this website, you'll find many sad tales of similar experiences.

I suspect the problem had nothing to do with being under yourself, but instead it had everything to do with being under the bridge. That is, the bridge blocking the GPS signal is what caused the problem , not the bridge blocking the control signal. Though maybe I'm wrong about that in this particular case if you lost the ability to see the view from the drone's camera.

If the detailed flight logs are posted, someone will be able to do a detailed interpretation without resorting to the guessing that I'm doing.

 

[Capt KO]

Agree with others, loss of GPS (blind) and unfamiliar with atti mode (no brakes) led to the crash. In atti the drone won't hold position and can be blown by wind and won't stop by letting go of the sticks..takes practice. Also, read up on loss of signal (LOS) and how the drone reacts. There are many instances where return to home (RTH) is not the best option, like under bridge. LOS choice also requires a GPS signal to function.
Sorry for your loss but it's pilot error. We all learn the hard way, human nature.

 

[AZDave]

Thanks. If the above is what happened wouldn’t it be common knowledge to not fly under bridges particularly when going under yourself? Surely if the connections good 4 miles away it should cope 15’ below the controller?
I’m not an expert in any mode but surely what I was asking the drone to do wasn’t so tricky?

You clearly don't understand how radio frequency energy at microwave frequencies work. Neither GPS signals nor WiFi control signals can penetrate all the steel that is likely to be in a large bridge, and both are essentially line-of-sight unless you're lucky enough to get reflections from surroundings. So no, there is no reason to expect either to work 15' below you when standing on a bridge.

Whether or not any of that is "common knowledge" is questionable, though. You aren't alone based upon many other posts I've seen on these forums.

 

[MS Coast]

I was stood on a bridge and lost all control as it passed underneath. No warning, nothing. It felt like the object avoidance went in reverse sucking the drone into the rocks.
DJI FPV.
DJI is investigating but this thought struck me as the only reason for the accident.
Thoughts please

If you want some real insight instead of guesses and speculation based on the scant information you've provided, post your flight log.

 

[JohnnyD913]

The only time I tried flying under a bridge a immediately started getting magnetic interference and even went into atti mode.
I quickly realized what was happening and was fortunate to get under control once away from bridge…
It affected my compass resulting in a near crash.
I fly a Mavic Pro btw..
Maybe that will shed new light

 

[Tarmactripper]

My guess is that it hit a side wall.
I've watched several YouTube videos about flying under a bridge so I could decide if I wanted to or no. One thing is of utmost importance: maintain visual contact as GPS contact will likely be lost, and that's when looking into the bridge tunnel. Some suggested partial trial entries, It takes practice and is risky.

I entirely agree, that it hit a side wall, as a newbie I could be wrong, but i've years of experience flying R/C helicopters, and only judging with what i've seen, as it passes under the bridge line of sight lost, big mistake, but sorry about your loss.

 

[Yorkshire_Pud]

@nowtleft. Sorry I can not find a flight log with an original DJI name, there are none on my phone, I must have emptied it. The names of logs on my my external storage are all modified.

 

[Tarmactripper]

Sorry I can not find a flight log with an original DJI name, there are none on my phone, I must have emptied it. The names of logs on my my external storage are all modified.

Hello Yorkshire_Pud, not sure your comment meant for me, but thought I'd say hello any way

 

[Yorkshire_Pud]

Hi Tarmactripper, sorry no it wasn't meant for you. Earlier in the thread I said I would check the log names as I have a recollection they do not follow the normal format

I will amend the post to make it clear it is meant for the OP.
Oh and hello.