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Air 2s crash - looking for the cause

PhuketAl

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Last week at a family gathering I launched my Air 2s, flew around my brother's yard a bit then offered the controller to my nephew-in-law (NIL), a fairly capable drone pilot from what I understood. So he's flying around the yard for a few minutes - doing some circles and other another manoeuvres. Before I looked away briefly I saw him swinging the drone side-to-side in a rocking motion about 6 feet off the ground which was making me nervous. No sooner did I turn my head to talk to my brother than I heard the drone hit the rock wall of my brother's house. It pulled away from the wall briefly then seemed to hug it as it slid down into the rock garden 4 feet below, grinding the props on the wall all the way down, landing upside down. I turned to look at my NIL and he was frozen with a stunned look on his face as he handed me the controller and I pulled the sticks to shut off the engine which had continued to run. NIL claims the controller became unresponsive suddenly causing the crash

Damage was fortunately limited to the props and the nose. Luckily, after replacing the props the drone still flies the same but it seems the sensor system was damaged by the nose hit since it constantly beeps as if there are obstacles present - even when I turn off the obstacle avoidance. Control is now somewhat affected with obstacle avoidance on so I solved that by turning off obstacle avoidance and turning the sound way down. The gimbal looks undamaged but won't finish re-calibration without me giving it a nudge with my finger. Result is that sometimes I have to adjust it in the air in order to get the horizon to look even after panning. There are no software error messages.

Anyway...I'm very curious as to how it happened and have attached the .txt file from my iPhone. I tried to find the .dat file but it appears it has been overwritten or deleted for some reason (I do not sync my flight data to the DJI server) since the folder that contains the .dat files only shows the last flight I flew.

Any insight would be appreciated.
 

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Phantomrain.org

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First thank your friend for taking the drone on a Carnival ride , ugh

I have seen every kind of magnetic interference and loss of signal and none of those action would result
in side to side swinging.

I think you have to accept that your Friend just had to much fun at your expense.

You can upload the Data File :
Go to DJI Flight Log Viewer | Phantom Help


Phantomrain.org
Gear to fly your Air 2S in the Rain and Land on the Water..
 

MARK (LI)

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Looks like a motor stopped at 6:49...not many satellites were available either..at 6:47 it was unable to hover because of week signal ...which could have been that rocking motion you observed...some guys are real wizzes with this and will be able to tell you what controls were in use
 
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Desert Sands

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Al:
First off, very sorry that your drone was damaged. As for the cause I'm sure one of forensic guys will give you a determination. However, I believe you already know what happened.

Two things stand out here.

1. You didn't mention if any apologies were offered... not that it would have made any difference in the outcome.

2. The swinging side to side is a an intentional action, I've not seen a drone do it by itself.

Now, I don't want to add insult to injury, but NEVER let anyone fly your drone. I have two rules, that I am strict about, 1. Nobody except my wife drives our vehicles. 2. Nobody but me flies my drones.

The reason for both is the same. Liability. Cars are a rolling liability, drones are a flying liability. If I hurt someone whilst driving, it's on me... and I have to make it right, if that's even possible. If I hurt someone with my drone... same thing....

If I loan my vehicle to someone and THEY hurt someone... guess who else will be sued? What if your nephew lost control and hit someone.... you (at least in the US) are responsible because even though you handed the controls to your nephew... you would still be considered the Remote Pilot in Command.

I'm reasonably sure you won't make that mistake again. I have been asked by friends and family if they can fly my drones... I politely tell them no, and explain they are tools, not toys... and I am responsible for anything bad that happens.

The great news is that the drone still flies, and a trip to DJI will fix the sensors.

Be thankful Nobody got hurt...

All the best,

Joe
 

MAvic_South_Oz

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I saw him swinging the drone side-to-side in a rocking motion about 6 feet off the ground

Well, lesson learned, always watch people you decide to trust with your drone, standing right there ready to take the controller . . . beginner mode to start is an absolute must.

It could be your NIL is a reasonable pilot on cheaper toy drones, which typically fly atti mode and need constant niggling of the sticks.
The motion you describe was probably him thinking he needed to fly like that, or he was just being a clown with your drone.

Anyway, there are at least 4 good analysts here and I'm sure one will be along for some input.

It sounds like there are at least some repairs needed here to get you back to a decent flight experience.
No cover through DJI ?
 
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Meta4

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Before I looked away briefly I saw him swinging the drone side-to-side in a rocking motion about 6 feet off the ground which was making me nervous. .... NIL claims the controller became unresponsive suddenly causing the crash
He might say that but it's bollocks.
He was whizzing around, pushing and pulling both sticks to their limits in all directions, like a monkey on meth.
That should have been enough to take the drone back from him.

Right up to the time of the collision, the controller was functioning completely normally.
The drone was fully under his "control" when it crashed.
You are just lucky that the crash occurred at low speed (2 metres/sec), just after he had changed direction and the drone hadn't had time to accelerate much.
 

Meta4

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Looks like a motor stopped at 6:49...not many satellites were available either..at 6:47 it was unable to hover because of week signal ...
Don't be fooled by the messages that show up after a collision.
The crash happened at 6:45.4.
GPS was not working well because the drone had fallen to the ground and was lying upside-down.
The only weak signal mentioned was GPS and that's explained above, as is the failure to hover.
 

PhuketAl

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Al:
First off, very sorry that your drone was damaged. As for the cause I'm sure one of forensic guys will give you a determination. However, I believe you already know what happened.

Two things stand out here.

1. You didn't mention if any apologies were offered... not that it would have made any difference in the outcome.

2. The swinging side to side is a an intentional action, I've not seen a drone do it by itself.

Now, I don't want to add insult to injury, but NEVER let anyone fly your drone. I have two rules, that I am strict about, 1. Nobody except my wife drives our vehicles. 2. Nobody but me flies my drones.

The reason for both is the same. Liability. Cars are a rolling liability, drones are a flying liability. If I hurt someone whilst driving, it's on me... and I have to make it right, if that's even possible. If I hurt someone with my drone... same thing....

If I loan my vehicle to someone and THEY hurt someone... guess who else will be sued? What if your nephew lost control and hit someone.... you (at least in the US) are responsible because even though you handed the controls to your nephew... you would still be considered the Remote Pilot in Command.

I'm reasonably sure you won't make that mistake again. I have been asked by friends and family if they can fly my drones... I politely tell them no, and explain they are tools, not toys... and I am responsible for anything bad that happens.

The great news is that the drone still flies, and a trip to DJI will fix the sensors.

Be thankful Nobody got hurt...

All the best,

Joe
1. Yes profuse apologies were offered and he offered to pay for repairs.

2. I guess I didn't make it clear in my post - but the swinging action was deliberate as I saw him do the same thing with a toy drone last year at his house. It was a swinging lateral U-shaped arc. I think he did that prior to doing acrobatics (flips) with his toy. I don't know if that was his intention in this case.

Lesson learned. You can bet that no one will ever lay hands on my controller again.

Al
 

PhuketAl

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Well, lesson learned, always watch people you decide to trust with your drone, standing right there ready to take the controller . . . beginner mode to start is an absolute must.

It could be your NIL is a reasonable pilot on cheaper toy drones, which typically fly atti mode and need constant niggling of the sticks.
The motion you describe was probably him thinking he needed to fly like that, or he was just being a clown with your drone.

Anyway, there are at least 4 good analysts here and I'm sure one will be along for some input.

It sounds like there are at least some repairs needed here to get you back to a decent flight experience.
No cover through DJI ?
I think you're right. I had only seen him fly his toy ATTI drone - at which he was quite skilled.

No DJI cover purchased. I bought it in Thailand (where I live) but as I'm in US for a few months I'll wait 'till I return to there have my DJI dealer in Bangkok get it repaired.
 
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MARK (LI)

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@Meta4 ....A few of you guys ...who have apparently been around for a while can figure all that out...and really good at it...how did you learn about it?...It doesn't seem like the kind of thing someone has written an instruction manual for....just repeated reviews of the flight data?
 

Meta4

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@Meta4 ....A few of you guys ...who have apparently been around for a while can figure all that out...and really good at it...how did you learn about it?...It doesn't seem like the kind of thing someone has written an instruction manual for....just repeated reviews of the flight data?
Sar104 put his thoughts on the topic together here:
I just flew a lot and learned how the drones work and started looking at the data in spreadsheet form.
 

slup

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...my nephew-in-law (NIL), a fairly capable drone pilot from what I understood.

Anyway...I'm very curious as to how it happened...

Mmm ... this wasn't anything else than careless flying with nearly only full stick deflections in close vicinity to objects ... had nothing to do with funky control signal or bad GPS reception (17-18 sats with 5/5 in confidence level).

As seen here below all the dashed graphs is stick movements (value 1024 = neutral) ... I've placed the marker in the chart where the last deliberate, non panicked stick inputs were made, that's at 404,4sec & only 9ft above the house roof (probably). At 405,4sec the crash occurs ... that's only 1sec from full deflections with the aileron, elevator & throttle sticks into one direction ... not near the needed time to break & change direction from full descent to full ascent, & from full roll (aileron stick) left to full right.

(Click on the chart to make it larger)
1627388373275.png
 

GrafXXX

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He might say that but it's bollocks.
He was whizzing around, pushing and pulling both sticks to their limits in all directions, like a monkey on meth.
That should have been enough to take the drone back from him.

Right up to the time of the collision, the controller was functioning completely normally.
The drone was fully under his "control" when it crashed.
You are just lucky that the crash occurred at low speed (2 metres/sec), just after he had changed direction and the drone hadn't had time to accelerate much.
I must add that I will be stealing and using your words probably on a daily basis. To quote “ like a monkey on meth.” has to be one of the greatest phrases to describe someone that I have heard in a long time
 
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hiflyer201

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Sorry for your loss and since the would be pilot offered to make it good hurray for him. Swinging wildly from side to side would indicate to me a red flag lack of skill but you can re-live the entire exciting flight and watch the stick movements in real time right on your app. Maybe you already know that.
 

BudWalker

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Last week at a family gathering I launched my Air 2s, flew around my brother's yard a bit then offered the controller to my nephew-in-law (NIL), a fairly capable drone pilot from what I understood. So he's flying around the yard for a few minutes - doing some circles and other another manoeuvres. Before I looked away briefly I saw him swinging the drone side-to-side in a rocking motion about 6 feet off the ground which was making me nervous. No sooner did I turn my head to talk to my brother than I heard the drone hit the rock wall of my brother's house. It pulled away from the wall briefly then seemed to hug it as it slid down into the rock garden 4 feet below, grinding the props on the wall all the way down, landing upside down. I turned to look at my NIL and he was frozen with a stunned look on his face as he handed me the controller and I pulled the sticks to shut off the engine which had continued to run. NIL claims the controller became unresponsive suddenly causing the crash

Damage was fortunately limited to the props and the nose. Luckily, after replacing the props the drone still flies the same but it seems the sensor system was damaged by the nose hit since it constantly beeps as if there are obstacles present - even when I turn off the obstacle avoidance. Control is now somewhat affected with obstacle avoidance on so I solved that by turning off obstacle avoidance and turning the sound way down. The gimbal looks undamaged but won't finish re-calibration without me giving it a nudge with my finger. Result is that sometimes I have to adjust it in the air in order to get the horizon to look even after panning. There are no software error messages.

Anyway...I'm very curious as to how it happened and have attached the .txt file from my iPhone. I tried to find the .dat file but it appears it has been overwritten or deleted for some reason (I do not sync my flight data to the DJI server) since the folder that contains the .dat files only shows the last flight I flew.

Any insight would be appreciated.
Is it possible that NIL is used to flying FPV drones? Looking at the control inputs it looks like that might be the case. Unlike the MA2 when the elevator, aileron or rudder stick is released a FPV drone doesn't return to neutral. E.g., inputting some aileron rolls the FPV but it won't then roll back when the aileron is released.
 

PhuketAl

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Sorry for your loss and since the would be pilot offered to make it good hurray for him. Swinging wildly from side to side would indicate to me a red flag lack of skill but you can re-live the entire exciting flight and watch the stick movements in real time right on your app. Maybe you already know that.

I know how to replay a map-based view of the flight by clicking on the flight record in the app. Where would I see the stick movements?
 
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wardtom084

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Anyone flying should be using AirData and look at what happened. I have let several newbies fly my drone. It is altitude plus altitude. You can't beat that. Never let any one fly at less that 200 to 300 feet in my book.
 
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PhuketAl

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Mmm ... this wasn't anything else than careless flying with nearly only full stick deflections in close vicinity to objects ... had nothing to do with funky control signal or bad GPS reception (17-18 sats with 5/5 in confidence level).

As seen here below all the dashed graphs is stick movements (value 1024 = neutral) ... I've placed the marker in the chart where the last deliberate, non panicked stick inputs were made, that's at 404,4sec & only 9ft above the house roof (probably). At 405,4sec the crash occurs ... that's only 1sec from full deflections with the aileron, elevator & throttle sticks into one direction ... not near the needed time to break & change direction from full descent to full ascent, & from full roll (aileron stick) left to full right.

(Click on the chart to make it larger)
View attachment 132426
Thanks for the analysis, much appreciated.
 
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