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[Resolved] GPS Module Failure? Need to return for repair.
3038 24 2016-3-25
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Old Geezer
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Flight distance : 23691 ft
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My 2 month old Phantom 3 Advanced just fell out of the sky on approximately it's 10th flight.

I'm new to multi-rotor so I've been taking my time getting used to the P3A and not pushing the envelope at all.

The flight where it failed was it's second flight of the day in the same location - one of our big open beaches here in Northumberland UK.

The first flight went smoothly with full control and testing various altitudes between -0.1 metres and approx 70 metres, plus various flight directions (forwards, backwards, sideways plus level, climbing and descending as well as rotating while doing those).  It's my longest flight to date at around 6 minutes and roughly 1200 metres flight path.

Raw footage from the flight immediately before the one that crashed over the same beach ... as in the crash flight was 2 or 3 minutes after this one, with the battery still having around 65% power on recovery of the bird.



Notice the unexplained switch from "follow" mode to "FPV" mode between  5:30 and 5:40 into the video when I turn the aircraft and the horizon  suddenly flips by about 20 degrees?  No idea what happened there. Any ideas?

The 2nd flight started well too - flew out straight from home at 15 metres above home, then tilted to 90 degrees down to get some video of the sea lapping on the beach, and did a slow pull back flight curving gently back to home.  Half way back added a slow climb too - like I said I'm a full learner and was practicing flight control.  Unfortunately, though I thought I'd pressed video record, it looks like I didnt ... so no video of this flight - aaargh.

About 2/3rds of the way back to home, the P3A suddenly tumbled out of the sky.  Watching the flight log replay shows it inexplicably started flipping between P-GPS and P-ATTI at the point where it started to fall, until it hit the ground then remained on P-ATTI.  I'm a little suspicious that it suffered some sort of failure to the GPS unit because of this.  (Edit to add - the healthydrones flight analysis seems to say it was not the GPS unit - see below).

According to the sand stuck to the bird, it landed on the starboard rear rotor arm end, and threw the prop.  It also popped out the plastic LED cover of the starboard front lights, which we have been unable to find and recover.  Worst of all, it also now suffers from Gimbal Pitch Error & Gimbal Roll Error and gives a D D D - D D D - audible warning on start up (with rotors off).  The camera does not do it's start up dance, and the lateral movement of the gimbal arm feels very loose as if disconnected from the motor's natural braking of movement.  The motors do start from the CSC on the RC, but sound a little "raspy" - not as smooth and quiet as they used to.

The green LEDs give a double green flash (safe to fly) with P3A, RC, and DJI Go all fired up.

I've synchronised the flight logs to the cloud in the app, I'll upload them here if I can figure our how and where to - can anyone give me a clue please on that one?

Before raising a support ticket, is there anything else I should do?  I'm hoping it can be repaired under warranty if it proves there was a hardware or electronics fault, but if not then I still want to get it back and in the air asap.  Of course, this had to happen on the first day of the Easter break

Can anyone offer any advice for what to do next please?





2016-3-25
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Old Geezer
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Flight distance : 23691 ft
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I've now uploaded the two flight logs to HealthyDrones.com and you can see them here -

First flight (no problems & video above = https://healthydrones.com/main?f ... amp;page_id=GENERAL

Note: the flight times and durations show the P3A was on the ground approx 1 minute between flights.

Second flight (which ended in a crash) = https://healthydrones.com/main?f ... amp;page_id=GENERAL


From the results there, it looks like the compass went bad, not the GPS module ... the drone retained a 100% / 15+satellite GPS strength throughout, even after it crashed into the sand.
2016-3-25
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Old Geezer
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Flight distance : 23691 ft
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DJI Moderators - I've now submitted a ticket (# 184603) please ask support to ensure they review this thread.

Here's a couple of images that may be useful - they are screenshots from the video in the OP (the flight immediately before the flight when the P3A crashed) and relate to the simulated flight path and flight analysis at exmaps.com - https://www.exmaps.com/acefc7 - which contains data for my assertions below these pictures ...

Crash flight command locations

Crash flight command locations


T/O = Take off point
R/C = Remote Controller Operator (static) location
C/C = Compass Calibration position
H/C = Hand Capture aircraft recovery position


Flight path composite from exmaps.com and previous flight's video

Flight path composite from exmaps.com and previous flight's video


Take off at 17.29m GPS & Barometer - - but actual was only 2 metres above mean high water line ... does this mean the GPS and barometer were faulty?

A = Alt 33.67m, 02:27mins - hover to turn on video capture in DJI GO (or so I thought - it never started)
B = Alt 32.75m, 02:50-02:55mins - Rotate drone and begin backwards flight curving slightly to shore
C = Alt 31.27m, 03:06mins - Begin tilting camera upwards very slowly
D = Alt 35.47m, 03:38mins - Begin climbing and change from curving left rearward flight to sideways flight towards home
E = Alt 57.56m, 03:49mins - Aircraft began uncontrolled tumbling descent and changed direction to northwards trajectory (instead of southwest towards R/C)
F = Alt 26.12m, 03:53mins - Attempted full throttle climb to slow uncontrolled descent ... marginal response (paused the fall momentarily)
G = Alt 17.67m GPS / 17.82m Barometer, 03:55mins - Impact ... luckily about 5 metres inland of the then water's edge, battery ejected and one prop flew off - battery was still switched on when recovered, and had approx 60% power remaining.


From the simulated flight path and flight analysis at exmaps.com - https://www.exmaps.com/acefc7 - I glean the following ...

- From 03:48mins until impact at 03:55mins, there was sudden and massive compass "interference" according to exmaps.com's extraction from the .DAT file - did the compass unit fail?

- During the same period, the GPS satellite count held steady at 18 satellites with a momentary dip to 16, however there was an increasing difference between the reported height by GPS and Barometer ... could the barometer have been skewed by flying in and out of cloud shadows. as well as over sand and water - air temperature and density changes?

- From 03:48 to 03:55 the X, Y, & Z axis accelerometer graph shows massive vibration - probably the aircraft trying to correct the tumbling - it doesn't explain why it started tumbling.

- Power drain is as expected, based on commands to aircraft, until 03:48mins when power use falls off dramatically to about the level previously shown for a stable hover, even though the bird is tumbling and trying to right itself, as backed up by the Roll, Pitch & Yaw graph ... shows power may not have been fully reaching the motors during the uncontrolled descent, even though all else was working normally, or that the aircraft had locked at "hover power" while tumbling.

2016-3-26
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AG0N-Gary
Captain
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United States
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After watching so many crash videos and reading explanations of what they did, I'm really beginning to suspect a chicken and egg thing.  Instead of loss of GPS causing the crash, I think something else it causing loss of control by the flight system, and the loss of GPS is caused by the bird doing so much tilting and flipping (some are upside down when they spin down) that the antenna is actually losing lock on the satellites.

Good luck with your claim.  So far, no unexplained downings with my P3A.  Just my own error, for which I replaced the affected parts.
2016-3-28
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Old Geezer
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Unfortunately Gary, although I am a fairly advanced PC support tech, I wouldn't consider myself competent to perform parts changes on my Phantom ... it's one thing to do swap outs to the innards of a box that'll sit on a desk, but another entirely to do them on a machine that'll fly.  (Maybe it's a self-confidence and training issue ... are there training courses for drone repairs?).

Geezer
2016-3-29
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Homestead72
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Old Geezer Posted at 2016-3-29 10:01
Unfortunately Gary, although I am a fairly advanced PC support tech, I wouldn't consider myself comp ...

Sorry to hear about your crash.

I am UK P3A flyer like you and have had my Phantom for a similar time as you.

And like you have been taking small steps in order to learn the ins and outs...

...the fact that this is unexplained is really worrying though.  I personally would be really grateful if you could update this thread with the DJI analysis when you get it and the final outcome?

Cheers
2016-3-30
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Old Geezer
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Homestead72 Posted at 2016-3-30 09:26
Sorry to hear about your crash.

I am UK P3A flyer like you and have had my Phantom for a similar  ...

Hi Homestead,

Where in the UK are you?

Sure I'll update the thread once everything is resolved, in the meanwhile I've also opened a discussion thread here - http://forum.dji.com/forum.php?m ... mp;page=1#pid359658 - for experienced pilots to give their input on the incident.

Cheers
2016-3-30
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Old Geezer
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I've just finished putting together a reconstruction from the DJI Go app flight logs - here's the video

2016-3-30
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Homestead72
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Old Geezer Posted at 2016-3-30 11:39
Hi Homestead,

Where in the UK are you?

Hi Geezer,

I am on the South Coast (West Sussex).  Haven't yet had the bottle to take my P3A over the water yet though!!

I'll take a look at the other thread as well.
On your video of flight log above you mention two accounts....one for user and one for aircraft??    I wasn't aware that we had two accounts.  Can you give me any more details about this?

Cheers for now.
2016-3-30
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Old Geezer
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Homestead72 Posted at 2016-3-31 08:56
Hi Geezer,

I am on the South Coast (West Sussex).  Haven't yet had the bottle to take my P3A over  ...

It has me a little baffled too - I think when you register you create an account for you as the user, then each drone you connect to via the app gets an account too.

However if that's true, then something is mammaries upwards in the app's code, because my P3A seems to have 2 accounts (both containing the same flight records) - one as a P3S and one as a P3A - with neither of them showing the log for the crash flight ... that only shows in the user's log (i.e. mine).
2016-3-31
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Homestead72
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Old Geezer Posted at 2016-3-31 12:02
It has me a little baffled too - I think when you register you create an account for you as the us ...

How do you change the login 'username' though to access these different flight logs?  From within the app?
2016-3-31
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Old Geezer
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Homestead72 Posted at 2016-3-31 20:29
How do you change the login 'username' though to access these different flight logs?  From within t ...

If there are multiple accounts recognised by your app, when in the flight records screen there will be chevrons (arrows) each side of the avatar at top left of the page.  Tap them to scroll right or left through the list.  The avatars and the name on them will change .  If you watch the flight reconstruction video I posted above, you will see what I mean during the first 30 seconds or so of the video.
2016-4-1
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Homestead72
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Old Geezer Posted at 2016-4-1 13:04
If there are multiple accounts recognised by your app, when in the flight records screen there wil ...

Thanks. I see now. I also have two accounts (me and the Phantom). The logs in them are exactly the same though. It is odd how yours were different....  Perhaps some kind of sync issue conflict?
2016-4-1
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Old Geezer
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'Struth ... how long does it take Support to decide on an RMA?

After emailing them on 25 March (the day of the crash), I got a non-automated reply on the 30th (yeah I know it was Easter weekend, but the 30th was the Wednesday after the holiday).  I replied to them immediately with the info they wanted, which included synching the flight logs to the cloud.  

(The dealer (Quadcopters UK) had replied the day before, 29th March, and issued an RMA number at the same time, including an offer to pursue the warranty side of it with DJI - now THAT is customer support and service and shames what DJI have achieved so far.)


Next day (31st) DJI Support Holland emailed to say they needed to see the DAT files from the drone and I immediately uploaded them to DropBox - they confirmed on 1 April (Friday) that they had them.

I chased them up on Wednesday 6th April for a progress report and same day got a sort of "it'll take as long as it takes" reply.

It's now the 8th and a full week since they confirmed receipt of the FLYxxx.DAT files and still no results from their "analysis" nor an RMA number for the repair

Come on techies - surely by now you have figured out that the drone hit nothing in mid-air, and that there was no pilot error, therefore the drone needs returned for physical inspection leading to repair under warranty?  After all, it took NASA less than this time to figure out why the Challenger Space Shuttle broke up in 1986!

DJI-Ken or DJI-Amy - please could you chase this up for me?  (ticket number #184603)  The P3A had less than one hour total flight time when this "drop from the sky" happened.

Thanks in advance ... and on behalf of my P3 Advanced.

Geezer
2016-4-8
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DJI-Tim
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Old Geezer Posted at 2016-4-8 21:00
'Struth ... how long does it take Support to decide on an RMA?

After emailing them on 25 March (the ...

Sorry for your experience with customer support!  I'm escalating your case, our colleagues will get in touch with you.
2016-4-10
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DJI-Tim
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Our colleagues already got in touch with you and brought up a solution.
2016-4-11
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Old Geezer
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Many thanks DJI-Tim - I received the RMA number and instructions today ... I'm now just waiting for the Collection information and date/time (and shipping label - not sure if one of those is sent or not).

Hopefully the repair and return will be swift ... I'm eager to get flying again.

Geezer
2016-4-11
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Old Geezer
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Update -

After taking a week to analyse the flight logs, and DJI-Ken's kind intervention, an RMA number and return collection was organised.  UPS uplifted the box on Monday this week and their online tracking system shows it was delivered to DJI Holland today at 1:36pm, signed for by "Been".

Hopefully they'll repair and return it quite quickly now ... fingers crossed.

Geezer
2016-4-20
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gtokarsk
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Gosh! Good luck! Hope to hear what they determine! That is one thing that keeps me from doing anything "funny" with my 2 week old P3 Adv! I don't even want to try Lichi app quite yet... keeping it all stock ;) Your gimbal was really working hard during the tumble! Amazing to see all the tools that can be used to look at it though.. Healthy Drones is not the least of them ;)
2016-4-20
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Old Geezer
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Flight distance : 23691 ft
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It's back!  It's back!

And I've just spent the last 4 hours updating the firmware in the R/C because the new innards they put into the drone included an aircraft firmware update to 1.08.0080

What a palaver!  Could someone pass on to the software devs the difference between "download update", "downloading update", and "downloaded update" please?  Because they use "download update" for all three stages in the process and make it completely unintuitive.  At least they got "installing update" correct.

Now to get everything fully charged up and hope tomorrow's weather is like today's to do some test flights
2016-5-4
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Old Geezer
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GOOD NEWS !!!

Test flight today in the field at the back of the house was flawless.  I only flew with the sticks and did one return to home test (scary how high 30m looks in an open field) but it did everything I asked.  I filmed during the 2nd half of the flight and seem to have acquired a slight horizon tilt, but as there was a slight wind with gusts to around 12mph I'll wait for a calmer day (tomorrow according to the weathermen) to verify that.

At 1.5m off the ground doing a hover stability test in P-Atti with a full set of satellites and VPS on, the bird was a bit "drifty" horizontally and vertically.  But again it may have been the wind today (and the GPS is only supposed to be stable to a 1.5m horizontal accuracy anyway).

Big shout out to the service techies in Holland for a first class repair job, and to DJI-Ken and his team for pursuing the case when it seemed to be taking a long time.

Many thanks all.

Geezer
2016-5-5
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DJI-Tim
DJI team

China
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Old Geezer Posted at 2016-5-6 10:00
GOOD NEWS !!!

Test flight today in the field at the back of the house was flawless.  I only flew ...

Great ! Customer satisfaction is important for us! Thanks for your positive feedback!  
2016-5-5
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calls4u2
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Old Geezer Posted at 2016-5-6 03:00
GOOD NEWS !!!

Test flight today in the field at the back of the house was flawless.  I only flew ...

Hey Geezer, in the same area as you, and looks like maybe in the same business!

Surprised they sent it Holland when we have a DJI repair centre just a little to the South of us?

Great that you have her back
2016-5-6
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DJI-Ken
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Old Geezer Posted at 2016-5-6 10:00
GOOD NEWS !!!

Test flight today in the field at the back of the house was flawless.  I only flew ...

That's great, I'm glad it's all sorted out and your bird is back and you are enjoying it
And thank you so much for the kind words, all of us really appreciate it,
2016-5-6
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Old Geezer
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@calls4u2

I'm mid-Northumberland (just outside Alnwick) - where are you?  ... I've started a Northumberland thread in the meet-ups forum, maybe best to switch over to there for replies.

I had the initial option of return to seller (Quadcopters in Lancashire) for repairs (they were very fast with RMA authorisation) or wait for DJI and know it would all be done with full warranty cover.  I chose to go for the DJI route for peace of mind.
2016-5-6
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