Mini 2 crashes into the Singapore river during night flight. Crash analysis request from amateur.

[toothless]

1 week new mini 2 drone pilot, and absolutely loving the experience. Flying daily over land had been comfortable thus far.
Overexcitedly flew the mini 2 over a large body of water Marina bay during evening time- with no issues. Tried once more at night time resulting in a crash.

Wind: low, satellites 11, batt 89%
Take off was smooth, along the bay - adequate signal and RC transmission. After hovering stably for several seconds, I rotated the drone clockwise so that the camera could face myself and friends.

Thereafter, the drone suddenly started flying forward despite there being no input on the controllers. Wind was a gentle breeze and was not fast either. The drone abruptly jerked and sped forwards, and I tried to direct it back but it continued flying forward and hit a structure.

After it hit the structure, it went into the Marina Bay sands river and was lost, unretrievable despite a futile attempt diving in.

I’m devastated but trying to figure out how to avoid such mistakes in the future.

I have a video from my iPhone of the whole incident as well.

From reading the threads- learning points
1. Ensure home point updated first (was not updated when I took flight)
2. VPS affected in low light conditions so ensure take off point is well lit

Flight details:
(Appears to be extremely limited data collected before the crash)

Also have a video documenting the entire flight - with flight records

Dji crash - Google Drive

drive.google.com

I’m keen to learn from this experience and will sincerely appreciate if anyone might be able to give additional lessons/ pointers/ tips from the misadventure.

Also wondering if this is human error from ignorance or a malfunction - leading to this crash.

Many thanks to anyone who is able to help this noob pilot right here!

 

[Meta4]

Thereafter, the drone suddenly started flying forward despite there being no input on the controllers. Wind was a gentle breeze and was not fast either. The drone abruptly jerked and sped forwards, and I tried to direct it back but it continued flying forward and hit a structure.

The data is almost useless as it doesn't show any of the flight and just shows 8 seconds at the start of the takeoff.
It doesn't show any flight or your joystick inputs and ends just as the drone is lifting off.
If that's the correct file, there's just one piece of information that might help when combined with something in your description.
Do you remember what direction your drone was pointing when it was on the ground for launch?

 

[aaron.m93]

Mate, you’ve shared a lot of personal info on your google drive. Full name, address, phone number. And heaps of cached videos in the videoCache folder. Best un-share this asap.

 

[slup]

...Do you remember what direction your drone was pointing when it was on the ground for launch?

It appears that the log-indicated yaw direction correspond well with the direction the Mini 2 shows in the video ... so don't think a yaw error is responsible for this.

From Video:

Ground


Just after take off ... note the neon striped building in the yaw direction ...


And here from GE showing the yaw direction the Mini 2 have in the log ...

...Appears to be extremely limited data collected before the crash

Yeah ... & that's unfortunate, furthermore it doesn't cover what we see in the video either. The commanded rotation you do there isn't included in the log ... this indicate that the log recording was interrupted due some reason (cable to mobile device came lose?).

Nothing useful is revealed in the log ... so this can only be a guess work.

But I suspect that the number of sats locked & the GPSLevel could have deteriorated when you ascended (big & high building just behind & to the right of you) ... & due to being dark the VPS sensor also lost track of the surface beneath it. All this would have left your Mini 2 without horizontal position hold ... either in full ATTI mode or in some pseudo GPS/ATTI state which we have seen in other cases before. When this happens the craft drifts with what's affecting it (wind) & stick inputs usually come in with delay & the control feel mushy & imprecise.

 

[toothless]

Mate, you’ve shared a lot of personal info on your google drive. Full name, address, phone number. And heaps of cached videos in the videoCache folder. Best un-share this asap.

Hey Aaron really appreciate this. Always better to be cautious. I’ve removed the document containing the details and left the phone vid as well as the cached vids which I am ok to share.

 

[Crouching Leopard]

1 week new mini 2 drone pilot, and absolutely loving the experience. Flying daily over land had been comfortable thus far.
Overexcitedly flew the mini 2 over a large body of water Marina bay during evening time- with no issues. Tried once more at night time resulting in a crash.

Wind: low, satellites 11, batt 89%
Take off was smooth, along the bay - adequate signal and RC transmission. After hovering stably for several seconds, I rotated the drone clockwise so that the camera could face myself and friends.

Thereafter, the drone suddenly started flying forward despite there being no input on the controllers. Wind was a gentle breeze and was not fast either. The drone abruptly jerked and sped forwards, and I tried to direct it back but it continued flying forward and hit a structure.

After it hit the structure, it went into the Marina Bay sands river and was lost, unretrievable despite a futile attempt diving in.

I’m devastated but trying to figure out how to avoid such mistakes in the future.

I have a video from my iPhone of the whole incident as well.

From reading the threads- learning points
1. Ensure home point updated first (was not updated when I took flight)
2. VPS affected in low light conditions so ensure take off point is well lit

Flight details:
(Appears to be extremely limited data collected before the crash)

Also have a video documenting the entire flight - with flight records
DJI mini 2 jonas ho - Google Drive

I’m keen to learn from this experience and will sincerely appreciate if anyone might be able to give additional lessons/ pointers/ tips from the misadventure.

Also wondering if this is human error from ignorance or a malfunction - leading to this crash.

Many thanks to anyone who is able to help this noob pilot right here!

Sorry you lost your drone. Data analysis will be useful but I reckon the reasons are fairly straight forward

Flying at night means no visual positioning system. Also flying low you had no GPS lock. This would cause the drone to in effect be in Atti mode and difficult to control if not experienced.

Next, any reflections of light the sensors did pick up could have caused the drone to drift with them.

Finally, in atti mode, even a slight breeze will cause the drone to drift in its direction.

My advice. Re-read the manual, don't fly near water until your experienced and don't fly at night.

It's exciting to get into drones but it has its learning curve.

I worked in and visited many of those buildings you filmed many years ago and used to go kite flying near Marina bay. It is a beautiful place to capture. Don't let this be the end. All new pilots make mistakes. Carry on learning. It's worth the effort.

Finally, lock your google drive up, it's wide open.


Check your domestic insurance, you may be covered

 

[toothless]

It appears that the log-indicated yaw direction correspond well with the direction the Mini 2 shows in the video ... so don't think a yaw error is responsible for this.

From Video:

Ground
View attachment 146139

Just after take off ... note the neon striped building in the yaw direction ...
View attachment 146140

And here from GE showing the yaw direction the Mini 2 have in the log ...

View attachment 146142


Yeah ... & that's unfortunate, furthermore it doesn't cover what we see in the video either. The commanded rotation you do there isn't included in the log ... this indicate that the log recording was interrupted due some reason (cable to mobile device came lose?).

Nothing useful is revealed in the log ... so this can only be a guess work.

But I suspect that the number of sats locked & the GPSLevel could have deteriorated when you ascended (big & high building just behind & to the right of you) ... & due to being dark the VPS sensor also lost track of the surface beneath it. All this would have left your Mini 2 without horizontal position hold ... either in full ATTI mode or in some pseudo GPS/ATTI state which we have seen in other cases before. When this happens the craft drifts with what's affecting it (wind) & stick inputs usually come in with delay & the control feel mushy & imprecise.

Hi Slup! Really appreciate the time you have taken to explain it. I’d seen your comments in Prev threads and feeling thankful for the input- a precious drone might be lost but at least lessons are learnt.

Im not too sure either why the flight log only recorded up to a point right before the crash, with no log of the yaw movement from my controller. The connection to the phone was secure throughout.

With the limited flight info and just the video I do think your postulation might be right - the large building behind me might have impacted the gps signal transiently causing this atti mode/loss GPS state. I had tried to pitch the drone backwards with the Right control while it headed forwards into the structure but it was really not responsive at that point. Or perhaps my actions would be too delayed by then.

Summarised learning points thus far for me are:

1. Good lighting at take off - if ever I fly at night (VPS sensors unreliable in poor lighting and risky over water)
2. Choose a more ideal take off location (Disrupted GPS risk if nearby large structures)

An expensive and painful lesson as I keep replaying the events in my head.
Thanks so much, Will await dji’s reply.

 

[Yorkshire_Pud]

1. Good lighting at take off - if ever I fly at night (VPS sensors unreliable in poor lighting and risky over water)
2. Choose a more ideal take off location (Disrupted GPS risk if nearby large structures)

An expensive and painful lesson as I keep replaying the events in my head.
Thanks so much, Will await dji’s reply.

Regarding
1) Lighting is important when you DO NOT have sufficient GPS for the drone to know where it is but if the drone does know were it is ,through GPS, lighting becomes less important.
Night flights (with sufficient GPS) are perfectly possible with the Mini 2 but the position control is not as exact because the lack of light prevents the VPS from working so be careful if near trees etc.

2) Also bear in mind possible steel near where the drone boots (the reason yaw and the drones direction were queried?).
You might like to read Sar104's opening post etc. in A short explanation of compass function, calibration and errors.

 

[Crouching Leopard]

VPS affected in low light conditions so ensure take off point is well lit

The VPS needs daytime light levels that probably wont be met with street lighting. Also Vps needs to work upto at least 5-10 metres and street lighting most likely wont be sufficient.

Check with Singapore's aviation authority, but I think night flying will most likely be banned without a permit anyway as it is in most countries.

 

[Crouching Leopard]

An expensive and painful lesson as I keep replaying the events in my head.

If you had care refresh, you might just be covered under fly-away. Its at least worth try . Log into DJIs customer service portal and just spend 5 mins submiting a ticket. You never know, you might win the lottery. There have been times when I have been pleasantly surprised at their response.

Don't beat yourself up about this incident. I have made more mistakes than myself or my wallet care to remember. Keep learning and never be afraid to ask questions. If unsure, don't fly. Become sure, then fly.

As an aside, I used to work in the building highlighted below. I moved in to the 21 floor whilst they were still building all the floors above. Talk about shortage of office space! My other place of work was Singtel HQ on Holland road and the old GEC company HQ on Bukit Timah Road. I lived out on the old army base at Seletar at the end of Jalan Kayu. My Daughter went to (what was then) Serangoon Central Primary school and my son was born in Singapore General Hospital. Great country, Great places.

 

[eEridani]

Triple supporting these learnings: having a GPS home point recorded is essential before night flight. If you don't hear the announcement from the DJI Fly app, do not launch. The few times I have launched without GPS the flights have been "interesting" in a not so funny way. Mostly all learned with my first non-DJI but GPS equipped drone.

And, the flight as you've described it sounds too much like a flight without adequate GPS locks. Then again, there have been a few Mini 2 crashes recently where the IMU appears to have problems. So be sure to reach out to DJI.

From reading the threads- learning points
1. Ensure home point updated first (was not updated when I took flight)
2. VPS affected in low light conditions so ensure take off point is well lit

 

[Meta4]

Triple supporting these learnings: having a GPS home point recorded is essential before night flight.

The data doesn't show much, but it does show that wasn't the issue