Weird behaviour from Air 3 - drone seemed to flip over then lost signal (possible bird strike?)

[MM2]

Hello all,

Am hoping to get some assistance please in regard to a flight with my Air 3 a few hours ago. Was about a minute or two into a flight when I noticed on the RC2 the drone seemed to flip sideways or upside down and I thought it was about to go down into the river below. It then suddenly lost connection to the controller and I was not able to gain any control over it, other than press the return to home button on the controller.

I breathed a huge sign of relief as the last picture I saw on the screen was the drone appearing sideways, looking like it was going down I and was convinced I lost it. Luckily, after pressing RTH it then began returning without issue. Landed it as soon as I could and checked the drone over as I was convinced it was a bird strike and was looking for claw marks on the props/on drone etc, but could not see any marks. I was confused though as a bird strike would not cause a loss in connection to the controller surely and I had visual line of sight. The props were all fitted properly as well as the battery inserted fully.

Upon looking at the video off the sd card, I could not identify any bird that may have flipped it over and also did not hear any obstacle avoidance sensor going off on the RC2 as far as I can remember. Unfortunately, was not doing a screen recording as I could then have noticed if a bird was close to the drone.

I do know I was close to some large power lines and I thought I may have clipped some wires, but reviewing the video footage again showed the drone had not reached the wires and so ruled that out.

I ended up moving to a local park a short time later, putting he drone back up using the same battery, flew for 20 mins or so and there were no issues with the flight. So would really like to know what may have happened on the previous flight and whether I should send it into DJI for assessment.

The only things I can think of possibly are a bird strike, a sudden and momentary loss of power or some type of interference from the power lines nearby. With any of these possibilities though, I can't fathom why signal was also almost immediately lost straight after the drone lost control/flipped. I guess it could also be an internal component fault, such as the motherboard, but unsure if that could cause the behaviour witnessed on this flight.

Link to flight video: DJI_20240317102110_0002_D.MOV

Link to flight log: DJI Flight Log Viewer - PhantomHelp.com

Appreciate any thoughts on what may have been the cause. Thank you.

 

[Yogi053]

That looks like your propellers showing in the video at the end. Areyou sure you didn't clip a powerline? I've seen other videos where users have done thsi and effected a recovery.

 

[MM2]

That looks like your propellers showing in the video at the end. Areyou sure you didn't clip a powerline? I've seen other videos where users have done thsi and effected a recovery.

Hey mate, thanks for your reply. Yep those are definitely the props you can see I think. I thought for sure I must have hit those powerlines too after initially looking at the video but upon zooming in on the map, it looks like the incident happens a bit before where the big powerlines are actually located. I"m pretty certain those ones visible on the map are the only ones there. I can't be 100% certain though. I also don't know if it would cause the sudden loss of signal directly after the drone appeared to flip.

 

[Vic Moss]

Just a thought...

You were pretty close to those power lines, but I don't think you hit them. However, you were close enough to be affected by the RF emitting from the lines. High tension lines will do that.

My guess is that this wasn't the drone doing that. It never turned completely upside down according to the video. I think instead of your drone dancing around in the sky like that, it was your gimbal. The RF may (key work "may") have affected your gimbal cable. Or, it's possible your gimbal cable is loose.

I've seen video like that from drones with bad gimbal cables. They dance around at start up.

Again, just a guess. Especially since your drone flew home after you hit RTH.

 

[GDadd]

The exact same thing happened to me with the Air 3 about a month ago. I didn't post about it because it was in camera mode and had no video to show. I thought it had been struck and lost it for sure.

As I recall, about 15 seconds passed before it reconnected with the remote and showed it returning to home. I inspected it closely and found nothing that suggested it had been struck.

Per Vic's theory, I could only assume something affected the gimbal, but do not recall whether any power lines were in the area. I have flown the unit maybe 50-60 times since that incident and it has not happened again.

 

[Cafguy]

That is strange. I am with Vic Moss on this. I think the gimble went crazy not the drone and the RF explanation would fit perfectly. You can try and see if it will happen again at a different spot. if it happens at the new location you will have your cable replacement question answered. Away from those power lines you may not see this again.

 

[MM2]

Just a thought...

You were pretty close to those power lines, but I don't think you hit them. However, you were close enough to be affected by the RF emitting from the lines. High tension lines will do that.

My guess is that this wasn't the drone doing that. It never turned completely upside down according to the video. I think instead of your drone dancing around in the sky like that, it was your gimbal. The RF may (key work "may") have affected your gimbal cable. Or, it's possible your gimbal cable is loose.

I've seen video like that from drones with bad gimbal cables. They dance around at start up.

Again, just a guess. Especially since your drone flew home after you hit RTH.

Thank you Vic for that response, you may very well be right. At first glance it looks like the drone is flipping around at all angles but may just be the gimbal moving abruptly creating that effect. I completed a subsequent flight in a park a short time later for 20 mins and no strange behaviour from the drone or gimbal was witnessed. Hopefully was the RF from the powerlines causing the issue as you suggest and therefore just a one-off occurence. Thanks again for your input.

 

[MM2]

The exact same thing happened to me with the Air 3 about a month ago. I didn't post about it because it was in camera mode and had no video to show. I thought it had been struck and lost it for sure.

As I recall, about 15 seconds passed before it reconnected with the remote and showed it returning to home. I inspected it closely and found nothing that suggested it had been struck.

Per Vic's theory, I could only assume something affected the gimbal, but do not recall whether any power lines were in the area. I have flown the unit maybe 50-60 times since that incident and it has not happened again.

Hello GDadd, yes it seems a strange one doesn't it and your incident seems very very similar to mine. Being so close to the high voltage powerlines as I was, you would think that could possibly be the cause. After checking the details on Air Data (warnings etc), there was nothing that looked amiss to me. And I don't recall hearing the obstacle avoidance sensors going off, so that would tend to rule out a bird strike, although can't be certain.

Hopefully nothing wrong with any of the internal components of the Air 3, although there is always a chance some units may get through QA with something amiss.

Thanks again for sharing your similar experience.

 

[MM2]

That is strange. I am with Vic Moss on this. I think the gimble went crazy not the drone and the RF explanation would fit perfectly. You can try and see if it will happen again at a different spot. if it happens at the new location you will have your cable replacement question answered. Away from those power lines you may not see this again.

Thanks a lot for your response Cafguy. I hope you and Vic are correct and it was just the powerlines/RF being the culprit. The drone has been flawless since I got it in November and as I mentioned, the 20 minute flight directly after in a different spot was incident free.

I had heard/read about possible effects from flying close to power lines and the like, but wasn't sure if this was just a myth or not.

I must admit, just looking on the RC2 screen at the time of flight, I was unaware just how close I was to the powerlines. I was shocked when I reviewed the video and was sure I must have hit them. That wasn't the case upon closer review though, but as you and Vic mentioned, the drone may very likely have been close enough to the lines for the gimbal to be affected as it was.

Thanks again for your advice.

 

[HoozierDroneDaddy]

Just a thought...

You were pretty close to those power lines, but I don't think you hit them. However, you were close enough to be affected by the RF emitting from the lines. High tension lines will do that.

My guess is that this wasn't the drone doing that. It never turned completely upside down according to the video. I think instead of your drone dancing around in the sky like that, it was your gimbal. The RF may (key work "may") have affected your gimbal cable. Or, it's possible your gimbal cable is loose.

I've seen video like that from drones with bad gimbal cables. They dance around at start up.

Again, just a guess. Especially since your drone flew home after you hit RTH.

Just a thought...

You were pretty close to those power lines, but I don't think you hit them. However, you were close enough to be affected by the RF emitting from the lines. High tension lines will do that.

My guess is that this wasn't the drone doing that. It never turned completely upside down according to the video. I think instead of your drone dancing around in the sky like that, it was your gimbal. The RF may (key work "may") have affected your gimbal cable. Or, it's possible your gimbal cable is loose.

I've seen video like that from drones with bad gimbal cables. They dance around at start up.

Again, just a guess. Especially since your drone flew home after you hit RTH.

Vic, The Air 3 has the new Ocusync 4.0. I thought I read somewhere that it now has a third frequency involved. I have flown around these power lines a lot as have others with no issues. Could the new added frequency be a weak spot for this interference and it's just being discovered? I wonder how many others have had this happened and they are not saying anything thinking it was just a fluke. Just a thought.

 

[StevenBrodsky]

Looks like a gimbal wobble attack to me. Ive seen some of my old drones do that after they had minor accidents. Even as minor as a 1 foot drop onto the kitchen table. It usually stopped after a little tinkering or just stopped for no reason.

 

[RodPad]

I seen this thread this morning. chose not to watch the video just played back the flight log.

Wondering before I view the video, does the flight log match the video.

Thanks in advance.

Rod ..

 

[msinger]

does the flight log match the video

It appears to be the correct flight log. The area of interest is missing since it occurred while the aircraft was disconnected from the remote controller. That's what ultimately caused it to return home.

 

[MM2]

I seen this thread this morning. chose not to watch the video just played back the flight log.

Wondering before I view the video, does the flight log match the video.

Thanks in advance.

Rod ..

Hi Rod

The flight log is definitely the correct one that matches the flight video. According to AirData, at 2.51 seconds into the flight, the image transmission signal was lost. This happened very shortly after I noticed the gimbal/drone acting all weird on the RC screen. At that time I thought for sure it had gone down into the water. I tried to take control manually but was not able to, so pressed RTH on the controller hoping that might bring the drone back. I was shocked when a short time later, RTH initiated and I got telemetry back on the screen. Returning home the drone showed no abnormalitiies, i.e gimbal movements etc.

Whatever happened though, the drone or gimbal moving erratically occured first and then the sudden loss of signal very shortly after, that I do know for certain.

 

[MM2]

H

It appears to be the correct flight log. The area of interest is missing since it occurred while the aircraft was disconnected from the remote controller. That's what ultimately caused it to return home.

Hello msinger. When you say the area of interest missing (when the drone was disconnected from the RC) is important. I would have thought the moment the gimbal/drone started to move erratically would be the critical point in time to look at?

I am very likely incorrect though and thats why I wanted to get the post up here on the forum as I knew several of you here are experts in analysing these situations.

I only wish I had the DAT file (I believe it's called) to upload, but the flight logs are synced to DJI I think as per my current settings.

 

[MM2]

T

Looks like a gimbal wobble attack to me. Ive seen some of my old drones do that after they had minor accidents. Even as minor as a 1 foot drop onto the kitchen table. It usually stopped after a little tinkering or just stopped for no reason.

Thanks Steven for your input. The drone hasn't had any crashes or anything like a hard landing etc. Hopefully will be the same situation as yours and just a one-off incident. Does make you a bit concerned though sending it up again and something similar or worse was to occur.

 

[MM2]

Vic, The Air 3 has the new Ocusync 4.0. I thought I read somewhere that it now has a third frequency involved. I have flown around these power lines a lot as have others with no issues. Could the new added frequency be a weak spot for this interference and it's just being discovered? I wonder how many others have had this happened and they are not saying anything thinking it was just a fluke. Just a thought.

Thanks mate for your thoughts. A google search shows the Air 3 operates on 2.4, 5.1 and 5.8 frequencies. The 5.8 is the new one I think. I have no idea if this may be related to what happened, but you raise a valid possibilty I think.

Looking at the video, I think it is a bit of an optical illusion where it seems the drone is actually closer than it looks to the powerlines (i.e. right on top of them virtually). But yeah, I wasn't really seeing them on the RC2 screen but I will definitely be keeping a larger distance to them in the future. Was also my first time flying at this location.

 

[TonyPHX]

Drones do not crash into powerlines. People with drones crash into powerlines. But seriously, my money is on what Vic said barring any other proof.

 

[Meta4]

You lost the downlink (the signal from the drone) but never lost the uplink to the drone.
This is why you were able to initiate RTH and explains why 10.5 seconds of flight data is missing.

We don't have data to show what happened in the missing 10.5 seconds, but we can try to fill in the blanks.
Before losing downlink, the drone was hovering.
It was 43.5 metres higher than the launch point and you were pushing on the left stick to climb at 2.7 m/s.
10.5 seconds later it was 3.5 metres higher and 3.5 metres further away from the home point.
It was stable and just starting to fly towards home in RTH.
From this we can tell that the drone did not fall during the 10.5 seconds.

I noticed on the RC2 the drone seemed to flip sideways or upside down

This indicates that the scary video happened before you lost the downlink.
But the flight data before downlink was lost doesn't show any erratic moves from the drone.
This suggests that what scared you was a gimbal glitch and not a collision with an unseen object.
Your drone never lost control or flipped.

 

[MM2]

You lost the downlink (the signal from the drone) but never lost the uplink to the drone.
This is why you were able to initiate RTH and explains why 10.5 seconds of flight data is missing.

We don't have data to show what happened in the missing 10.5 seconds, but we can try to fill in the blanks.
Before losing downlink, the drone was hovering.
It was 43.5 metres higher than the launch point and you were pushing on the left stick to climb at 2.7 m/s.
10.5 seconds later it was 3.5 metres higher and 3.5 metres further away from the home point.
It was stable and just starting to fly towards home in RTH.
From this we can tell that the drone did not fall during the 10.5 seconds.


This indicates that the scary video happened before you lost the downlink.
But the flight data before downlink was lost doesn't show any erratic moves from the drone.
This suggests that what scared you was a gimbal glitch and not a collision with an unseen object.
Your drone never lost control or flipped.

Thanks so much Meta4 for that detailed explanation. Everything you say makes sense to a layman such as myself. Just a question though, do you think the drone being quite close to those transmission lines could have had any negative impact on the gimbal to make it glitch so erratically? Such as RF interference as suggeted by Vic and some others?

Thanks again for taking the time to look into it, much appreciated.