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Distracted Pilot = Crashed Inspire - LESSON LEARNED
814 15 2016-3-19
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I1ADDICT
lvl.3

United States
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I had an IMU failure last night while flying at about 7-10 feet off the ground, which set me going down into the ground since it threw a error on the screen, distracting me, and in an incredibly lucky move I somehow managed to maneuver my way out of it but barely scraping my camera along the mud for all of a second of sheer terror.  Believe it or not my camera is perfectly fine and everything works as fas as i can tell, check out the pics! but I firmly believe this is directly related to the firmware update as I've never had anything like this happen and it's a little too coincidental immediately after a f/w update.  I also noticed weird anomalous behavior where my display would completely cut out and then come back and it did this on the IOS and Android, but seems to be way worse on the Android.  No aircraft update was supposed to have happened, but I had a complete IMU failure after doing the update so perhaps the IMU has a link to the RC somehow?  I've worked in IT long enough to know if something like this happens immediately after an update you have to blame the update, although coincidence, is a possibility.
I cleaned up my camera make sure the joints and everything looks good put it on the Inspire and fired it back up and it looks like everything works flawlessly!  So go DJI! there's a video of the incident as well (trying to get it uploaded) and as you'll see, I am not sure how I managed to keep it in the air. Pure skill i am sure. ;)

I can't get the URL timeline thing to work, so jump to 7:54 seconds to see the point of impact.  Please be gentle...I know I probably paniced and was distracted by the IMU error, but I am amazed I saved it.  Check it out:



x3 Mud Packed

x3 Mud Packed

x3 Mud Side Shot

x3 Mud Side Shot

x3 Mud Bottom

x3 Mud Bottom
2016-3-19
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Alastair
Second Officer
Flight distance : 96631 ft
Canada
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Video doesn't work for me.  It says I have to sign in but I'm already signed in.
2016-3-19
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I1ADDICT
lvl.3

United States
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Just updated it with another link...please give it another try if you can.
2016-3-19
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Donnie
Captain
Flight distance : 3636782 ft
United States
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I1ADDICT Posted at 2016-3-19 09:35
Just updated it with another link...please give it another try if you can.

Video would not work ( Says Private ). Also strange because this update was only for the Camera and Gimbal, maybe there was more to the update than we thought ?  As a rule of thumb I always Update IMU and Re-calibrate compass after a FW upload.  Glad you accident was not worse.

****Did it say IMU failure or was it a compass warning? .   " Please be gentle ". (LOL)..What do you think everyone is going to rip on you for an accident ???  Shit happens NO Worries Mate  !

Good Luck - donnie
2016-3-19
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I1ADDICT
lvl.3

United States
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Donnie Posted at 2016-3-19 08:01
Video would not work ( Says Private ). Also strange because this update was only for the Camera and ...

Doh!  Ummmm...yeah, sorta helps if the video is PUBLIC...so sorry Donnie/Gents.  

I always calibrate my compass before all flights, but I haven't calibrated the IMU in the options, so great tip.  I am doing it right now!

Yes, that's what drew my attention away from the video, all in red lettering "IMU failure" in the upper right corner...then it (I assume) went into ATTI mode for a second, which caused me to start to lose altitude and my "hold on to your lugnuts" moment. lol

Lessons Learned:
1.  In any emergency situation, RELEASE forward stick immediately and climb climb climb (unless indoors or under something obviously)
2.  When you have a new update, wait at least a week.
2016-3-19
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daver/m
Second Officer
Flight distance : 206503 ft
United States
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Looks like your low level flight across the pasture ended as the ground elevation slightly changed rising in front of you,
low level flights with speed can be tricky and trick your eyes as you look across the field seeing the ground fairly flat and level, until contact happens.
This is what I see watching your flight video.. Flying low skimming the terrain has caught me a few times, even at the local soccer field which looked flat and level.
Another thing is if your flying low don't take your eyes off the camera fpv view until you gain some decent altitude.. be ready with your left thumb on the power
in case you need to gain some altitude when skimming the terrain. Glad your machine is o.k.  Your video looks like Washington state somewhere ?  
2016-3-19
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I1ADDICT
lvl.3

United States
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daver/m Posted at 2016-3-19 09:27
Looks like your low level flight across the pasture ended as the ground elevation slightly changed r ...

Yeah, my flight logs shows me just start to decend, but no down on the stick, so your probably right as all subsequent tests in the field accross from me this am show ATTI mode does NOT cause me to lose altitude, just drift.  So I am leaning towards pilot error when I looked away at the IMU message, the terrain changed and I looked back just in time to see the chaos unfolding.

The IMU thing worries me...but thanks for the recalibration idea.

Yes, I am up in the Pacific Northwest, 20 mins from Washington....Hillsboro, Oregon to be exact.   Good call!
2016-3-19
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I1ADDICT
lvl.3

United States
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Nevermind...I can't recalibrate the IMU...I was thinking about the IOC option.  Anyways, yes, I always calibrate my compass when I get to a new location.
2016-3-19
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Donnie
Captain
Flight distance : 3636782 ft
United States
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I1ADDICT Posted at 2016-3-19 11:45
Yeah, my flight logs shows me just start to decend, but no down on the stick, so your probably righ ...

    I would not calibrate that compass before every flight if you stay within a 100 mile radius of calibration point you are fine. Just do it once and do it properly, keep the transmitter back about 15 feet make sure not metal on your person or in the surroundings and you are good.   The only times I calibrate compass is after a FW upload or travel out of the 100 mile radius or hard landing.    The best way to test your compass and IMU is to let it hover in calm winds, see if any major drifting ,  also do  a RTH and see how close it comes to the takeoff point.  If within 6 feet you are aces if not re-calibrate.
Hell I thought you were in OHIO..................on second thought maybe I should calibrate my compass more often.........

** I think you should lower your gimbal wheel speed also for a smoother video when Panning up, sya around 30 ish.  Just a suggestion.

good luck and have fun-  Donnie

2016-3-19
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daver/m
Second Officer
Flight distance : 206503 ft
United States
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I1ADDICT Posted at 2016-3-19 09:45
Yeah, my flight logs shows me just start to decend, but no down on the stick, so your probably righ ...

I think your right on doing an imu cal and compass cal before you fly again..
Sometimes a light tumble can change things. Oregon that makes sense.. The farmland just looked like Washington..I'm on Whidbey island north of Seattle.  It's a good day for flying and photography, I'm gone.
2016-3-19
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I1ADDICT
lvl.3

United States
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daver/m Posted at 2016-3-19 10:06
I think your right on doing an imu cal and compass cal before you fly again..
Sometimes a light  ...

Amen...better safe than "oh shit". lol

It didn't tumble/hit the ground at all from what I can tell, just the camera dragged/spun and the craft managed to lift off without any damage.  What's crazy is the motion, it looks so insane I thought for sure it was going to be a hike to go get the thing in the middle of a muddy field.
This really does remind me of how quickly things can change and some of those longer flights could turn into a very crappy retrieval weekend. lol  Gosh that would suck.

I am off to fly too...a couple of spots near the coast I want to see from the air.  We're headed up to Long Beach one of these weekends, the air shots should be amazing.  I keep playing with settings and such, I am new, but man is this stuff a blast.  The freedom to fly like this is unexplainable man, and then couple it with tunes and it's beyond a zen moment for me.  Bluetooth headphones are the ultimate.
2016-3-19
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LICENSED PILOT
First Officer
Flight distance : 644833 ft
United States
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Glad you were able to bring it down safely. I think that worrying too much about the display and forgetting we are still flying is an occupational hazard, and we've all done it. One of the first lessons I learned when I was a student pilot (1969) was that we are not done flying until the wheel chocks are in!
2016-3-19
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I1ADDICT
lvl.3

United States
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LICENSED PILOT Posted at 2016-3-19 11:48
Glad you were able to bring it down safely. I think that worrying too much about the display and for ...

EXCELLENT words of wisdom...really.  I think it's really easy to start focusing on the display and forget just how quick you could be down and on a very different experience...especially when I start geeking on my camera settings.  "oh shit!" lol
To me this is just practice for actually being in the cockpit.  I'd really LOVE to get my Pilots license someday and have been a Flight SIM guy for a loooooong time flying everything I could get into a SIM.  I even did the old Military RS360 about 15 years ago and it was a blast...although I almost puked.  
Anyways, back on topic.  
I did find the IMU calibrate option.  It was hidden under sensors.  It did recommend that I calibrate, so I did.
Heading out now, so we'll see how it goes.  I've check and rechecked everything.  All systems are go! w00t w00t.  
Thanks again guys for all the help/words of encouragement.  

2016-3-19
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Machoman
Second Officer
Flight distance : 1036959 ft
Austria
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For me it looks you just flew into the ground because the ground level rises a few meters while you were flying straight in one direction.

You know that the altitude it shows you - say 10feet - are meant over your starting point and have nothing to do with the ground level where the drone actually is. If the ground level goes up 10 feet you already crash though the display will still show you 10feet alt. Its very dangerous to fast fly over ground at low altitude.

I do not see an effect of an IMU failure here.
2016-3-19
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Harb
lvl.4

Australia
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Oh man, Good save, whatever reason it did it..........I bet your heart was beating hard there for a few mins haha
2016-3-19
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mtnmaddman
Second Officer

United States
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LICENSED PILOT Posted at 2016-3-19 12:48
Glad you were able to bring it down safely. I think that worrying too much about the display and for ...

Further any landing you can walk away from is a good one.   Addict,  glad your bird is alright keep us updated
2016-3-20
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