Hi to all,


I share with you a strange situation that occurred a few weeks ago. Any ideas from the forum as to what could have occurred here is greatly appreciated and might even assist others in this scenario


1. Sunrise shoot, weather fine, nil wind, low solar, elvation 2000'
2. Pre take off checks, Compas cal and imu check performed.
3. Aircraft status "Safe to Fly ATTI (no gps)....no signal at all
4. As the flight was no further than 60m from my location, I had no issue in flying ATTI mode. Out of habit, Recorded home point manually even though there was no gps
5. Took off, aircraft control check was fine.
6. Flew 2 passes of the area without issue. Returning for a 3rd pass, controls felt a little unresponsive compared to usual response rate
7. Decided to return aircraft to investigate.
8. Aircaft now approx 3m in front of me and 3m up. Struggled to stabilise it to lower the landing gear, small control inputs seem to produce a far greater effect on the aircraft.
9. RC SIGNAL loss displayed on status screen, aircraft powered up to what sounded like full power and shot off at a climbing angle of around 30 degress
10. Stick input on controller gone, I could only watch it fly away until it hit a tree around 20m away, aircraft destoyed

SO...........
(a) Where was it planning on going without GPS?.
(b)  A power cycle is meant to clear previous home point location....is this not the case?
(c) If power cycle clears home point, then what is the procedure for RTH if launch occurs without GPS? ( as per an inside flight)
(d)  RC signal loss with aircraft 3m away........ how could this be possible?
(e) Aircraft is designed to fly indoors and status would say as per my situation "Safe to fly atti, non gps" .....so is this correct or should we not fly without GPS?
(f) RTH ,  if aircraft received GPS at the point of losing RC signal AND the previous home point was still recorded, why did aircraft not    climb vertically to pre set altitude of 30m as per RTH documentation?

Aircraft had flown perfectly for 20 previous flights, software update ver 17 performed 2 days prior to this event

Any thoughts on this is appreciated. I also think that the questions above if answered may enlighten us all , DJI have the flight logs but I have had no response from them.

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Sounds like you should have been able to fly in Atti mode. I presume when you got the message reading safe to fly in Atti mode no gps you did switch into that mode correct? I have been reading of this happening to several other owners to a bigger or lesser degree than has happened to you. There are two common themes, we three actually. Fist. They all say, plane was flying fine for xxx number of flights before this. Second. They all noticed this behavior after the latest upgrade of version.17. And third. There was a notification of loss of GPS and a notable loss of radio control inputs. It really seems like flying the inspire right now is like a crap shoot. Seems we need another, nother firmware update. Good luck with yours. I hope you can get it repaired quickly and cheaply.

Was the home point set correctly? There is another thread someplace where they were thinking that the homeowner was set to their previous location and the I1 was headed to that home point instead of where you were

Luinil Posted at 2015-3-21 12:14
Was the home point set correctly? There is another thread someplace where they were thinking that th ...

Hi Luinil

that is one of the big questions.....does a power cycle reset the previous stored home point. Scondly,  what happens to the home point if the next flight is flown without any GPS signal and for what ever reason, fail safe is instigated automatically due to RC signal loss.

I think it would be great to know exactly what will occur in this situation....DJI please answer!!

inspire1flyer64 Posted at 2015-3-21 08:24
Sounds like you should have been able to fly in Atti mode. I presume when you got the message readin ...

Good points flyer64........I personally believe that either the new version of software has loaded with some issues or my machine has suffered some major failures on a few levels.
If it was the software alone, then I presume more people would be experiencing my pain at the moment!
Hopefully if we all keep asking the questions, the answers will eventually come
.....PLEASE JOIN THE CONVERSATION DJI

I had the exact same thing happen to me, I lost connection to the inspire the screen went blank it pitched to the right at the sometime and drifted until the connections was re-established. It happened very fast, lucky it did not crash.  Blade Strike requested my log files which I sent to him along with a video of what happened. My phantom 2 V3+ was in the air when it happened shooting video of the Inspire taking and recorded the event on vid.  Never heard a word back from Blade, I am sure it was sent to HQ for review.  I hope they get this straighten out soon. I love my inspire she is just a little temperamental at times..

MC

  

I have to think this out a bit, but I don't see how this could be an RTH behavior regardless of where it might think the home point was. If it were acting to go to the home point and that home point was more than 20m away (wherever that might be) then it should ascend to the altitude that has been preset. It clearly did not. If it was within 20m (again, wherever that might be) then it would land immediately. It clearly did not. So this is not about where the home point was and any RTH behavior...even if it had been triggered by the RC signal loss.

Of course that doesn't explain what it was doing. It just eliminates RTH and the home point from the list.

It also wasn't related to the Compass Error problem that I've experienced, which is always at the beginning of a flight and only occurs once. Because even when it happens, it just drifts. It does not power up and head in some direction.

So Compass Error is out.

Have to think a bit more about what else might be eliminated to see what's left to create that situation.

One thing you don't note in your opening description was the environment you were flying in, e.g., proximity to cell towers, antenna, other RC aircraft, power lines, proximity to complexes that might be emitting various signals, etc. Or were just in a park or open area with no notable structures nearby?

Hi bkackman

About 1km from cell tower, no other rc aircraft, no major power lines. Area was quite open as per the picture, flight was along the tree line, no notable structures

Sorry, pic did not attach, here it is of the location:

Bkackman and forum members,

Yes, it makes no sense what occurred. All we are missing is the voice of a DJI rep who should be able to answer the questions I have posed.

They are something that I have probable never needed to consider until now but if someone can answer them, then we will be all the better for it.

Did you switch the remote to ATTI or leave it in GPS because with a GPS signal it's kind of the same thing?   I wonder if in the middle of your flight it suddenly decided it had GPS and headed off to some unknown destination?   Just stabbing in the dark.    Guess you don't have a proper log of the flight because no GPS?

Hi Wolfman,
Does the flight record on your mobil device provide any clues?  The flight record usually shows when home is set and if it was successful, stick Inputs, mode, etc. If this is the same question Jimhare was asking, sorry.

I have to say that today, in my garden where I do all my test during a few years, I encountered also a few sudden losses of GPS. Then the copter was swinging quick from side to side on the Roll axes. (not a side swing as on manual mode !!!)  I was used for flying manual from the RC helicopter days so no problem to recover it. But all this going well because I look at the inspire during flying and not the image.

Second flight today.
- went ok for about 5 minutes
- message on the screen appears to switch to ATTI ( DJI please add a sound with this message !! )
- 15 seconds later (in ATTI mode) a red message of Compass Error  and control becomes a bit difficult

Landed: Did a new calibration

- 1 minute good flight
- same scenario , message to go to ATTI
- a few seconds later the red message of compass error
- 10 seconds later it's gone
- switch back to GPS mode
- ok for a little wile and then again the same scenario.

The inspire was flying good for 2 weeks without any problem.
Must be something wrong because as appear on the list I'm not the only one.

Almost forgot. Maybe important to add.
All this was happening together with a loss or disturbance of the camera image on my ipad.  Flying distance +_ 10meter.

info.gerdschelf Posted at 2015-3-21 23:46
Second flight today.
- went ok for about 5 minutes
- message on the screen appears to switch to ATT ...

Although you have calibrated your compass what are your compass mod values (at rest)?
The number will flicker around a bit but what is the ball park numbers your app is showing?

What should compass mod values be. Mine are 750 to 820 but my compass won't calibrate

it should be more than 1300++

mattks Posted at 2015-3-21 23:55
What should compass mod values be. Mine are 750 to 820 but my compass won't calibrate

Compass mod values should be between 1400 -1600 (1500 optimum) so I would say with mod values that low you have a problem!
Although slightly outside this range (1400-1600) is acceptible they shouldn't be THAT far out!

compass should be between 1400 and 1600

at rest
X: jumps between 45 and 106
Y:550
Z: 1400
Mod: 1508

info.gerdschelf Posted at 2015-3-22 00:08
at rest
X: jumps between 45 and 106
Y:550

In that case I would say that your compass mod value is pretty much spot on. However, the fact you are getting compass errors will be the reason your craft becomes difficult to control.
Until you get to the bootom of what is causing this issue I fear you will not have a very pleasurable flying experience and also run the risk of loosing control completely.
I would suggest you open a ticket with DJI and get the flight logs to them.
It may be of course that your Inspire is just more affected by the GPS/Atti bug than others and you need to wait out the new FW release........ I would still try and get the logs analysed by DJI though.

Shew. My mod values way out then. Compass calibration should fix that then? Or is the reason I can't get my compass to calibrate? Any opinions on whether the upcoming firmware could fix this problem?

mattks Posted at 2015-3-22 01:13
Shew. My mod values way out then. Compass calibration should fix that then? Or is the reason I can't ...

If your magnetometer (compass module) has become badly magnetised, possibly during transit or being stored near to a strong magnetic field (speaker etc) then sometimes the mod values simply cannot bring the error down into an acceptable range.
In the days of Phantoms and with the Naza flight controllers it is possible to degauss the compass module with a strong magnet to correct for such errors. I have not tried the procedure on an Inspire as I have never come across such a large error before. I guess you should contact DJI support in this case who will be able to tell from the flight logs the errors that are coming up on your compass unit.
The Inspire logs continuously (even when on the ground) when switched on so any failure of compass calibration will show in the logs.

strange, I did some 14 successful flights after the upgrade.
Doesn't give a safe feeling anyway.

Anybody an idea why the video transmission interrupt at the same time as the compass error occurs?

How do I pull the logs?

Open the app, click on the mode icon, advance settings and then Enter flight data mode. Right before you hit ok connect the craft to a computer via the rear USB port on the Inspire. It will open open just like a sdcard.  

jimhare Posted at 2015-3-21 18:27
Did you switch the remote to ATTI or leave it in GPS because with a GPS signal it's kind of the same ...

Hi Jim,

I did not switch to manual atti, left it in P mode atti. My take on the situation was that if GPS was restored after taking off then it would automatically revert back to P-gps. Happy to be told that this was the incorrect thing to do....you don't know if you do not know!

This is the big question that I think we ALL need an answer to.......I am lead to believe that a power cycle rests the home point. So what is the fail safe scenario for RC signal loss if the flight starts with no GPS and what is the RTH procedure without a gps home point?????

Flight log recorded but without mapping info, DJI has the logs. It would be nice if the experts at DJI could answer these questions so we are all a bit more enlightened.

TAHOE ED, please join in the conversation

dwaiteretired@g Posted at 2015-3-21 22:19
Hi Wolfman,
Does the flight record on your mobil device provide any clues?  The flight record usua ...

Hi dwaiter,

all questions are good questions in my book especially when you do not have access to the answers.

Tablet only shows the flight duration and max altitude (48m) No further info avaliable due to no gps. Still waiting on an answer from DJI for the data from the flight logs.

ALSO, I uploaded all flights to the cloud in the user section so there was a backup copy. In doing this, I found that total flights and flight times as displayed at the top of the user screen gets doubled!

Spoke to DJI help line, theya re aware of this and it will be fixed in the next update.

Wolfman Posted at 2015-3-22 17:48
Hi Jim,

I did not switch to manual atti, left it in P mode atti. My take on the situation was tha ...

Very sorry about what happened, could have been any one of us.  

Please keep us informed as more information comes in.

Cheers Jim, the hard part is not knowing the answer. Hopefully I will get one and my loss will hopefully help out all of us. Do you know how to PM ...I want to ask you a question outside of the forum.

Wolfman Posted at 2015-3-22 18:42
Cheers Jim, the hard part is not knowing the answer. Hopefully I will get one and my loss will hopef ...

I've never figured out how to PM but feel free to email me at jim at harebrained dot com dot au

Personally, I would not have taken off if I was not able to get a GPS lock in the outdoors.  That is an indication that there is a problem.  You said that you checked the IMU but when was the last IMU calibration?  If you were in P-GPS mode with no GPS and set the Home Point, the craft would not have recognized the home point.  There was no way for it to know where it was.  If during the flight it had GPS it may have set a home point while in the air.   We do not know.  The logs are the telling factor.  Can you send me a link to your logs and I will see if I can get a reading on them.  Have you opened a ticket with DJI?  If not I would suggest that you do so.  Please send me that link, plus your RMA or case number.  Also indicate what Service Center you are using.

mattks Posted at 2015-3-22 01:13
Shew. My mod values way out then. Compass calibration should fix that then? Or is the reason I can't ...

You need to calibrate your IMU.  The actual compass calibration is different.

Luinil Posted at 2015-3-21 12:14
Was the home point set correctly? There is another thread someplace where they were thinking that th ...

He had no GPS so setting home point would be impossible. He essentially took off without a home point, no GPS, and ultimately for whatever reason lost RC signal. Really this is a worst case scenario. It started the moment the aircraft was instructed to fly with a navigational error and no fail safe. This is tantamount to loading a rifle and not putting the safety on and then doing an obstacle course. I don't intend to be unkind with this, but the pre flight checklist was a fail and if this a real helicopter it would have never left the ground.  Also if this was a investigated by an aviation authority it would be classified as pilot error, regardless of the potential hardware or software failure. The reason is that the pre flight checklist was a failure and the pilot decided to fly in this state. Unfortunately Transport Canada or other agencies are rather blunt when an aviation incident occurs.

But, it is a model aircraft and he didn't intend to harm anything. So we should find a solution to this so we can prevent this from happening again. In a different environment that outcome could have been quite severe. So I suppose we start with the pre flight check list. It makes sense why we have them, so we should really drive home the need for all of us to use one and if any part of that list fails... Don't fly until we can make it right or understand fully what has gone wrong.

If IMU is wrong when startup. Then it goes wrong the first seconds of lift off. (he did 2 flying passes as described).
I lost an +25.000$ drone on an IMU problem starting up on a boat on the North Sea.  

So, seems not IMU problem to me.

Tahoe_Ed Posted at 2015-3-23 11:01
Personally, I would not have taken off if I was not able to get a GPS lock in the outdoors.  That is ...

Thanks for your reply Tahoe. I will get this info to you tomorrow. The case has been opened in China via my place of purchase. They also have the flight logs. I am yet to hear anything though

As for your comments, can you assist in clearing these things up:

Yes, maybe I should not have taken off without GPS BUT the craft is designed to do this as per indoor flights.

IMU calibration performed approx 4 days prior.

I presumed that without GPS, manually setting home point would do nothing. SO when I lost RC signal, where would the aircraft have been going to?
What is the fail safe procedure for the aircraft in these specific circumstances, I would have thought it would go in to a hover then land

If it was in RTH mode, can you confirm that the aircraft is supposed to climb vertically to its pre set RTH altitude then proceed. Mine took of rapidly at 30 to 45 degrees whilst climbing.