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Crash out of the blue
877 11 2015-8-23
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trrdesign
lvl.3

United States
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OK, so I have about 30 flights on my phantom 2V+, latest version, all hardware upto date.  Have had no problems up to now.  Today, flying some homes under design, went around first home.  Drove down to second and using same battery, went up to shoot.

All of a sudden, the drone shoots bakwards with no contorl, it angles towards the ground and hits and bounces and lands upside down.  No warnings, it just took off backwards and angled to the ground.

Battery came out.  So not sure if it was loose or something, but it had been flying fine.  3 propellers broken, the camera plate is bent, one cord came disconnected and the gimbal is slightly bent.    So went throug the whole thing, recalibrated everything, checked it on the desk to make sure everything spun up OK.  Battery now has to be really pushed in hard to finally click all the way in.

Took it back out after rebending the camera plate mount and did some tests.  E verything seems fine.

So some questions:
Any idea on why it would shoot backwards?  Was flying fine for about 10 minutes.
What should I look for on any other damage?  One arm separated a bit, but it looks like the screw was pulled through a bit. Unscrewed it and put it back in and it works fine.

Any help would be appreciated.

2015-8-23
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roy
First Officer

United States
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Tr, that's a thought one, if it had turned and crashed on a 45 angle down it would point to an ESC but haven't heard of going backwards. After the crash just check the motors to see thy turn fine and have about the same resistance. Check to be sure  none of the shafts are bent. If all looks good a couple of short out and low altitude test flights are in order. Have to gain confidence back that all is working well. Plug into the assistant and review the battery specs. Beyond that  hopefully al is good.
2015-8-23
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trrdesign
lvl.3

United States
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Thanks Roy.  I tested all of the motors and they moved correctly.  i then went through complete checks on both softwares, controller and Drone.  Went out and flew the basic square patterns and checked everything out.  it hovered, a little bit shaky, but it was a little windy.  Flew about 6 squares and it seemed to do fine.

It was definitely backwards, because i was filming the house and it flew away from the house.  It flew straight for about 40 feet and then went down in a field.  I need to photo the battery that popped out.  how do you know if it is still good?  Anyone?
2015-8-23
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billswanson89
lvl.1

United States
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A couple things I noticed....

You wrote...You DROVE DOWN TO THE SECOND... AND USING SAME BATTERY..went up to shoot...

A. You didnt say if you used a case when transporting/driving to the other location to shield/protect the compass?

B. You didnt say if you RECALIBRATED said compass... at the second location? (which I definately wouldve done if transporting a phantom by car between shoots.. btw wheather or not I used a case)

C. I dont think I wouldve used a baterry that I had flown for ten minutes prior for a "new flight" in a new location... but thats just me.... I just dont take off on partially used batteries.. and I think it makes a difference...

I have only had like three 'fly away' attempts  in 300+ flights /9 mos and they were all on a low or lower charge battery status, near the end of flights....once I flicked the S1 switch down one click to Atti... it stopped the 'fly away'  

Sounds like you might be in Phantom Mode...?
2015-8-24
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yorlik
lvl.4

United States
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billswanson89@g Posted at 2015-8-25 03:42
A couple things I noticed....

You wrote...You DROVE DOWN TO THE SECOND... AND USING SAME BATTERY..w ...

I've only probably had 150 flights in my 9 months of ownership of p2v3+ so not as experienced.

I have NEVER done a compass calibration since received and I have driven my phantom to various places during this time.  I question the validity of doing either compass or IMU calibration unless specifically called for.  

I have two batteries so never did a flight on a used battery.  my flights are normally about 10 minutes and then I consider my battery done until recharge.

I have never had a possible fly away situation so no need to flip to ATTI and back, but by gosh when/if I do, that is EXACTLY what my first step will be.
2015-8-24
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trrdesign
lvl.3

United States
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Thanks all.  Some clarifications:
Drove to house which was about 400 yards away.
I stuck the drone in the foam case, but did not zip it up.  
I always do the compass dance, no matter what.  
Battery was at about 70%.  
Not in Phantom mode.

So I was thinking the same thing on the battery.  When I found the drone on the ground, the battery was sitting next to it.  Possibly it was not fully seated or got jostled, driving the 400 yards.  Only thing I can think of, but it did not go straight down.  It shot off backwards and then dived into the ground.  I tried powering up, forward, nothing did anything.  Did not have time to turn off controller.

Will watch this thing carefully over the next few trips....
2015-8-24
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billswanson89
lvl.1

United States
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yorlik Posted at 2015-8-25 05:18
I've only probably had 150 flights in my 9 months of ownership of p2v3+ so not as experienced.

I  ...

I think.. Without a compass calibration.. Your phantom has no way of returning on its own in the event of a signal loss... and it decides to fly to whatever value is stored as the 'home point'  if your compass is properly calibrated.. that home point is likely to be where it took off from.. If it isnt properly calibrated? who knows?  

Even though the "home point" is recorded before take-off... it still relies on the compass to fly to it../find it...

Right?

As far as the ATTI switch.... I read that here..
that sometimes a phantom will try and 'fly-away'  because it following erroneous compass info..and switching to ATTI... takes the compass out of the loop.. Like dis-engaging an autopilot...

sure enough..When my Phantom took off in an un-commanded direction... despite flying fine for 70% battery, a quick flick to ATTI stopped it cold...
Infact.. I just got a new battery a couple days ago,  to go along with my two 120 charge cycle batteries that vision assistant says have 60%percent life left, and I've made a BUNCH of observations.. regarding the Phantom..and Batteries...
2015-8-24
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yorlik
lvl.4

United States
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I have often wondered, and a few times asked for survey, how many who have had fly offs did a compass or IMU calibration immediately beforehand;  I suspect it is very high percentage.....    Anytime you do either of those things you are taking a chance of messing up a working machine.  That is why I never do either and won't until the software tells me I need to either explicitly in words or by the values going out of bounds suggested in assistant.

Is there a way to do a questionaire/survey on here of another phantom pilot type forum?

Couple facts to help understand:

- Home point is NOT defined in anyway by the compass.
- Home point is ALWAYS undefined (aka gps coordinates 0,0 - off east coast of central africa) on power up - previous is NOT saved in phantom altho it is saved in some phone apps).
- ATTI takes ONLY GPS out of the picture;  compass is ALWAYS on in GPS & ATTI mode (only off in manual mode)
2015-8-25
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billswanson89
lvl.1

United States
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yorlik Posted at 2015-8-25 19:35
I have often wondered, and a few times asked for survey, how many who have had fly offs did a compas ...

Yeah.... Besides the placard..on my P2V+ v.3  that  reads 'calibrate compass before every flight'  Im not sure where I got in the habit of calibrating it everytime.. But since I fly exclusively over water...I figure it cant really hurt...

And Im not sure I understand your first point...
A properly calibrated compass IS necessary in Helping your Phantom RTH in the event of a signal loss.
Everytime  My Phantom RTH's on its own...Im glad that it has a properly calibrated compass to help guide it back... So it took an extra 45 seconds during the launch process to do it? to me..thats a vital step before each flight..

As far as ATTI taking GPS out of the picture...  Thats the whole point during a fly-away... because GPS is being fed by erroneous compass info , telling phantom where to go like an auto-pilot...maybe caused by an improperly calibrated compass..?

I was under the impression that the Homepoint was set/recorded during the phantoms start-up procedure?  ie: second set of rapid flashing green lights?  so Im not sure what you meant by 'home point is always undefined'

At anyrate... if not ever calibrating your compass is working for you...  thats good.. just goes to show.. that theres more than one way to fly a phantom..
2015-8-25
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yorlik
lvl.4

United States
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I'm ok with you disagreeing with my comment on not doing compass cal often.

i thought i was clear on gps coord=0,0 on power up before it sets (2nd set of grn fast flashes).  ok to disagree with me there too!

hey, your manual also says discharge ur batt to 8% every 20 charges - go for it to - says so in the manual & on the internet so must be true.  if you care, watch for my post soon with proof THAT is very bad for your batt.  but, dont consider my comments, dji has lots more money than me so they must be right.
2015-8-25
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yorlik
lvl.4

United States
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billswanson89@g Posted at 2015-8-25 20:41
so Im not sure what you meant by 'home point is always undefined'

sorry for confusing you by putting additional info in brackets, causing you to misquote me.

I did not say 'home point is always undefined'

I said "Home point is ALWAYS undefined on power up"

Big difference in meaning, huh?
2015-8-25
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billswanson89
lvl.1

United States
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Yeah... I have my Battery observations also... Since I just bought a new one and have been flying with it here and there... It affects a whole lot of things...

Apparently im Lucky to have two batteries with 120+ charge cycles on them... Performing  without issue at this moment.. I never deep discharged mine every 20 cycles  either.. FWIW...

But Im going to buy another new one..and regulate these older ones to back-up duty..


The other thing... I appreciate being able to come to forums like this and share what I have learned from flying my Phantom...  Actually flying my Phantom.  I read a whole lot of "info" on boards like these... supplied by people who may or may not have lots of experience actually flying phantoms.. so much so... that I had to actually stop visiting forums like this, for fear of being paralysed by everything that could ever go wrong with a phantom...  Not to argue with people who have different opinions than mine... Yorlik.. I sincerely meant what I said... Just like there are many ways to drive a car... Im sure there are many ways to fly a Phantom... Thats all I meant.

But Since I fly my Phantom every day..pretty much at the very end of its Signal range, over water... I know the relation between loss of signal, and RTH, and compass calibration , on MY particular set-up..
Thats all..



2015-8-25
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