Yet another fly-away

Steve Perkins · Jul 21, 2015

The Editor said:
Hi, welcome to the forum.

The version differences are not electronic - they are mechanical.
A-B Change of carbon fiber weave
B-C Supply of QR props
C-D Slightly redesigned landing gear mechanism (2 parts instead of 4)

Ok, so they are happening across the board then. Has anyone tracked the flyaways based on firmware version?

The Editor · Jul 21, 2015

Steve Perkins said:
Ok, so they are happening across the board then. Has anyone tracked the flyaways based on firmware version?

Well DJI do when they analyze the flight log data.

Steve Perkins · Jul 21, 2015

The Editor said:
Well DJI do when they analyze the flight log data.

I'd be curious to see the data for the number of flyaways on various firmware and various versions of the platform. Even if the changes from A-D are all mechanical, I think the information would be valuable.

The Editor · Jul 21, 2015

Steve Perkins said:
I'd be curious to see the data for the number of flyaways on various firmware and various versions of the platform. Even if the changes from A-D are all mechanical, I think the information would be valuable.

Valuable to who?
Contact DJI and ask them for the statistics......

Good luck.

Steve Perkins · Jul 21, 2015

Well... I would think it would be valuable information for anyone that was using a version of the firmware that is more prone to flyaways than another version. If so, they should consider upgrading. The same would go for the revisions of the Inspire 1 itself.

I'm not saying DJI would provide this information, but if someone is posting about a flyaway that happened to them, they could mention the version of the inspire they are flying, as well as, the firmware version.

Hercules_One · Jul 25, 2015

French said:
I am still trying to re-engineer what happened during the fly away. At this point, I only have the flight path from my iphone. Device seems beyond repair, but may be DJI has some secret tricks.

Some key lessons learned though:
a) DJI disables multiple flight modes following firmware updates as was pointed out above (not sure how they can be so stupid to erase the previous setting given the quality of the firmware), but according to my flight plan, I could not enter in ATTI mode although I tried. MAKE SURE TO CHECK THIS AFTER EACH UPDATE OF FIRMWARE.

b) The Inspire accelerated to 17.1 m/s horizontal speed during its fly-away which is 40 mph. Given the weight of the drone, this represents a substantial risk for hurting a physical person or damaging property (Ironically I was actually relieved that the drone crashed in a solid house rather than something else).

c) The range before crash in case of a fly-away is substantial which raises the question about the safety of flying in open spaces within agglomerations (at least from my personal point of view).

d) The most scary part for me is that there is still no complete explanation by DJI of what really happens (IMU and compass calibration seem to be one, but I also found post http://www.phantompilots.com/threads/anatomy-of-a-dji-flyaway.42997/ that indicates more serious issues).

I will keep you posted on DJI feedback following the fly-away report that I filed.

Hi, I'm sorry for your loss, I myself crashed my inspire 1 (my fault) but only brake bumpers and camera, so I had to buy another one. That felt terrible, very expensive.

With point a) are you confirming that that happened to you, so switch to ATTI is still safe? I agree, very stupid move from dji to reset settings, maybe they have a reason for that?

French · Jul 25, 2015

Hercules_One said:
Hi, I'm sorry for your loss, I myself crashed my inspire 1 (my fault) but only brake bumpers and camera, so I had to buy another one. That felt terrible, very expensive.

With point a) are you confirming that that happened to you, so switch to ATTI is still safe? I agree, very stupid move from dji to reset settings, maybe they have a reason for that?

I assume switch to ATTI is still ok, since I could not activitate it, I dont know for sure in the end. I am actually starting to understand why you can switch off the engines during flight, in case of a fly-away like I had that might actually make sense before someone get hurt.

STClassic01 · Jul 25, 2015

could it be that you couldn't switch to ATTI because the app went back to default?

JamesSpringPilot · Jul 26, 2015

sanderx said:
Having experience with DJI and their flight controllers (especially naza in the past) I rarely fly in GPS mode. Too many things are communicating with each other (GPS, barometer, gyro, compass, software) (ironically the app actually tells you to switch to GPS mode when you switch to atti mode) but as you said, GPS mode is just not 100% secure. Neither is flying solely in atti mode but it takes the risk down a factor in my pov.

If I take off with gps and then switch from GPS to atti mode, I know the inspire will drift with the wind freely, but will it maintain altitude? Is the craft able to hold altitude without input? What about updrafts?

lake_flyer · Jul 26, 2015

JamesSpringPilot said:
If I take off with gps and then switch from GPS to atti mode, I know the inspire will drift with the wind freely, but will it maintain altitude? Is the craft able to hold altitude without input? What about updrafts?

it will remain altitude within a few feet give or take.
The barometer supplies the info to the flight controller about the height. The IMU senses the velocities and pitches in all directions and the magnetic compass the nose heading. Although it doesn't use GPS to hold its position in Atti, GPS is still active and Fails Safe/Return to Home will function normally.

Guy Letourneau · Jul 26, 2015

Just to add to this thread.... My impression of how you described your crash.
I have much experience in flying the Inspire one. Which brings me to the conclusion that your problem was a flight control communication interference.
Here is how I reach my conclusion:
I have flown the DJI while the software HAS COMPLETELY CRASHED ON ME. This means that even if your software is not working, the Inspire one falls into manual control, allowing the pilot to control the craft despite the software's operation.
Now weather all the control processing is fully within the craft, Ie GPs positioning, compass, etc is irrelevant. If the controller is still in full communications with the craft, your directional controls are still active. If it did not receive your command to switch to manual, its an interference from your surrounding atmosphere. usually due to micro radio or other waves that can interfere.
To remedy this freak situation, DJI can come up with interference detector, a detector that would determine if an interfering signal is coming from anything other then the DJi controller and put the unit in auto landing mode.

Let me know if I am on the right track with my thoughts

Machoman · Jul 26, 2015

Would be interesting if such situations increased since they limited the number of channels in the Pilot App. Actually I believe that 95% of fly-aways are from interference or not calibrating compass. Also in some countries its rather easy to get jammers for Gps and 2.4Mhz. I would be interested how many fly-aways happened in countries where it is not so easy to get such devices like Germany, Austria, Switzerland.