S1000 flyaway and crash

[mkheng]

RCedit, sounds very much like a GPS fault to me. I was testing the other day with no problems. Had a break then went to do some more tests and exactly what you describe happened (almost). The problem I encountered was due to me not putting the GPS upright and leaving it in the transport position. Good job I was in the middle of my test field in the middle of nowhere. 'Don't fly whilst attached' ribbon now in place!


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[Ronan]

Well, logic would state that properly developed firmware would recognize a GPS glitch when it encounters one and wouldn't obligate the operator to have to "switch to manual" to prevent it from flying off to who knows where. I guess this is to be expected from DJI FC and operators just accept this as "normal" or "by design" way of dealing with it.

As long as the later is the accepted course of action, there is not much pressure on DJI to fix what should be considered a design flaw. :highly_amused:

Actually the A2 will switch mode if there's a lack of GPS signal called GPS Atti or something like that. When components fail, you have to switch modes, just like most FC out there. That's what most users do. It's not hard you just have to flip a switch.

if you want a system that does everything for you, there's some $50,000-$100,000 FC systems out there for you... Big price difference...

 

[sk8brd]

if the a2 is working right it should drop into atti with a less then ideal gps signal. there was a theory reported by experienced members that on earlier firmware like 2.2 the craft was dropping into a purgatory like land, not in gps or atti but somewhere dark and in-between which caused no control stick response in any mode..lol

side note-- knock on wood no issues with years of flying on any of my naza rigs. only time that something happened was when i was doing flip stalls with my phantom. i dropped to much altitude and bonked the ground with the landing gear. the bonk wasn't crazy hard but it hit and when i flew the craft up into a hover i switched from manual mode to atti it started to bank right. i switched between gps/atti /manual at least 5 times and every time in atti or gps it would bank right ...manual mode was always fine.. i landed did a power cycle all was well. i wonder if any the crafts that exhibited issues were crashed ever?

one thing i will say is Ronan is right there nothing 100% in the world,. but in some cases in regards to dji fc's the firmware i firmly believe are to blame even on wkm and its not just user error. too many rigs went down the same week after upgrading to 2.2 and dji admitted what the problem was and fixed it which was good. i know a guy with 100's of flights on a2 he had it the first week it came out and never had an issue...kloner reported many flights without issue before retiring it so there not all bad.

 

[gtranquilla]

I get the impression that the Multirotor can go haywire, if after locking in it's GPS position before take-off, the new GPS data coming in becomes bogus, i.e., is substantially offset from the home location. This condition would not be a loss of GPS signal but a new and faulty GPS position significantly offset from the FC recorded GPS location. In such a situation, taking off in GPS mode would cause the MR to immediately attempt to reposition horizontally to the newer home location, hence a possible crash or a fly-away.

 

[RCedit]

Thanks for the thoughts. I'm still curious about the fact that my A2 was shipped running different versions of Main Controller and IMU firmware, which DJI advises against in it's latest A2 release (or risk a crash). I haven't found that stipulation in any of their previous releases. Does anybody know if this is in fact a new stipulation or if it has been advised from the start?

 

[1Placerville]

Well...I dont know guys...I've had one of my 1000's do what he is describing but a bit more violently. I had it in GPS mode when it suddenly dipped steeply left and began rapidly descending. I flipped it into Atti mode and regained control before it hit the ground. Scared the crap out of me but I now know that when in GPS mode and it starts to do weird things flip to Atti...just my experience, dont know if it would have worked for you but it worked for me.

 

[dazzab]

What can be done about this? I keep reading about these issues and really it seems unacceptable that such expensive equipment can end up as junk through no fault of the owner. Can you imagine the outrage if a certain brand of car just decided to steer in to oncoming traffic once in a while?

You may recall the incident in Geraldton Australia where a women was struck by an out of control DJI copter. I've been told by very reliable sources that they reproduced the radio interference that caused that incident proving that it was not the operator who caused the incident. So here we have proof that DJI equipment can go out of control from radio interference yet no one seems to think this is an issue.

IMHO, they should stop the sales of DJI equipment until this issue is resolved. I bet that would finally get DJI to start cooperating in having their code reviewed and to prove that their systems are reliable enough to be considered safe for flying.

 

[RCedit]

To be fair, the exact cause of my crash hasn't been determined. I'm pretty sure it was not pilot error but the flight analysis should be happening soon. I hope to post DJI's official 'cause' of the crash along with the mark ii flight log for cross-reference as soon as I hear from them.

 

[222GR]

Rig had been working beautifully on a 2 day shoot. Had probably 15 flights without issue. On my last battery/flight, I ascended to 15-20 ft and the coper immediately began strafing right. Slowly at first but quickly accelerated. Tried to correct by rolling left but that seemed to increase the speed going right. Same with yaw. It only took about 8 seconds for it to find the woods about 75 yards away. Broke my centerplate and I'm sure one of the motors is toast since it's full of bark. Tremendous bummer.
I've been up all night going through everything in my head and I just can't deduce a theory of what happened. Until I do I'm not going to be terribly comfortable lifting off again once I get it repaired. Any opinions of what may have occurred?
s1000
A2 (GPS mode)
LightBridge
GH4

Thanks

out of curiosity do you have a flight radius limitation set in the software?
i learned an interesting lesson the other day about GPS mode, home points, and walking a powered aircraft to another takeoff point other than its recorded home point. Just something to think about.

 

[RCedit]

No fence set in software.
The previous home point theory is interesting but the A2 searched and locked on satellites and the flyaway direction was the opposite from previous takeoff spot.

 

[222GR]

without knowing for sure, I'd tend to agree with with faulty gps data auto flipping to limbo mode or Atti without your knowledge.
It happens fast and its realllllly easy to try and over-correct for an out of control aircraft (not that you did)
flipping the physical and mental switch to atti may have saved the day but you may never know. Hopefully when you get your rig back there will be some resolution and you can pull the data and see for yourself what may have happened.

 

[1Placerville]

Heres a video of how fast you can lose control courtesy of "Old Fart".

 

[blkupspilot]

I ost a Tarrot 690 similarly...i put to 5000mah batteries on it for more flight time. It lifted off fine and flew for 12 minutes before it did what your video displayed. I think the ESC's thermal out but I can't be sure....still scratching my head over that one...Lost everything!

 

[RCedit]

From DJI (all under warranty):
We have replaced the top/bottom frame, GPS bracket, A2 flight controller, A2 IMU and propellers. The A2 firmware has been updated to the latest version using the A2 assistant software 1.4.
The LightBridge ground station board has been replaced with the new V2 board. We also replaced the old antennas with new pancake antennas.
The GH4 gimbal has been re-balanced and calibrated. The HD/AV firmware has updated.
The S1000 was test flown and fully operational.
Make sure to calibrate the compass in every new flight location. The compass is very sensitive to electromagnetic interference, which can cause abnormal compass data leading to poor flight performance or even flight failure.
Do not calibrate your compass where there is a chance of strong magnetic interference, such as magnetite, parking structures, and steel reinforcements underground. Do not carry ferromagnetic materials with you during calibration such as keys or cellular phones. Do not calibrate beside massive metal objects.
The customer support through the entire ordeal was very good (says he who had his rigged fixed for free ). I'm waiting to have a detailed convo with the technician about what exactly happened but the context of the email from them seems to indicate a GPS malfunction.
Thanks for your thoughts along the way.

 

[dazzab]

From DJI (all under warranty):
The customer support through the entire ordeal was very good (says he who had his rigged fixed for free ). I'm waiting to have a detailed convo with the technician about what exactly happened but the context of the email from them seems to indicate a GPS malfunction.
Thanks for your thoughts along the way.

It's great to hear that they honoured the warranty. I guess that's about the best that could be expected in this case. I would feel much better if someone independent would review DJIs code to ensure there is proper sanity checking on GPS data and that the failsafes trigger and operate as they should. I'm becoming very suspicious that their code is not as robust or tolerant of faulty sensor data as it should be.

 

[Rentakill]

What mode were you in when the incident happened. Shame you didn't have enough time to turn the controller off or switch to manual mode.

Actually tahoejmfc is spot on with his comment, which was not insulting at all. In most cases it is operator error.

We won't know until we see some logs and DJI inspects the wreck. It could be faulty hardware (that happens) or something came lose.

I'm honestly surprised the OP didn't switch mode, that's my first reflex if/when something goes bad. Changing to manual means that even if the GPS came lose or is broken, means you can bring your craft back with no to little problems depending of your skills.

Most people just panic and flip the RTH switch... which isn't much help if you are having a GPS problem (like solar flares are messing with it for example).

That's why its very import for all operators to have options, manual mode is a good one to have
Glad you got it fixed

 

[1lifefilm]

Rig had been working beautifully on a 2 day shoot. Had probably 15 flights without issue. On my last battery/flight, I ascended to 15-20 ft and the coper immediately began strafing right. Slowly at first but quickly accelerated. Tried to correct by rolling left but that seemed to increase the speed going right. Same with yaw. It only took about 8 seconds for it to find the woods about 75 yards away. Broke my centerplate and I'm sure one of the motors is toast since it's full of bark. Tremendous bummer.
I've been up all night going through everything in my head and I just can't deduce a theory of what happened. Until I do I'm not going to be terribly comfortable lifting off again once I get it repaired. Any opinions of what may have occurred?
s1000
A2 (GPS mode)
LightBridge
GH4

Thanks

Hi There
I was sorry to hear about your crash......nightmare. Whilst I've been flying large model aircraft for 35 years I'm still relatively new to the multi rotor scene and I have to say that whilst the technology we fly is very clever I can't help thinking that our machines (mines an S1000) are hugely vulnerable to system failure, far more so than most of us think. Multi rotors are essentially unstable, fly by wire machines with each element of the system being fundamentally critical to basic control (MCU, PMU, IMU). The snag is that there is pretty much no redundancy and each of these systems are dependant on each other which makes matters significantly worse, there are so many weak links its a miracle that there aren't more incidents like this. I'd like to see much more redundancy built into FC systems moving forward. Simon

 

[Rentakill]

Hi There
I was sorry to hear about your crash......nightmare. Whilst I've been flying large model aircraft for 35 years I'm still relatively new to the multi rotor scene and I have to say that whilst the technology we fly is very clever I can't help thinking that our machines (mines an S1000) are hugely vulnerable to system failure, far more so than most of us think. Multi rotors are essentially unstable, fly by wire machines with each element of the system being fundamentally critical to basic control (MCU, PMU, IMU). The snag is that there is pretty much no redundancy and each of these systems are dependant on each other which makes matters significantly worse, there are so many weak links its a miracle that there aren't more incidents like this. I'd like to see much more redundancy built into FC systems moving forward. Simon

I agree to disagree considering the insurance companies are now offering gr8 packages for commercial UAV's. If the industry was unstable I'm sure the insurance companies would be the first to act. UAVS are like any machine, with good maintenance and products most will fly for hours without issue.

Throw in some bad piloting and unmangaed batteries and you have a real accident to happen. Most governments around the world are regulating the UAVS, which is a big plus for all users.

 

[DNAPDX]

1lifefilm

Did you by any chance change the compass direction and not re-calibrate? Did you ever find out what caused the crash?

 

[aceresco]

Hi I was the same problem whit A2 Flight away an lost all satellites ,I change to manual mode immediately an I can return my machine an landing. Next week be sending A2 to DJI they impectioned an confirmed the GPS be bad an this was my problems they replaced an resolved problem


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