Howdy,

TL;DR - I destroyed my brand new Phantom 4 on my inaugural flight in beginner mode. Did I completely funk up? Was my drone performing erratically?

Full Story
After doing weeks of research and pouring over documents and videos, I purchased a Phantom 4 on Friday at my local Apple Store for an upcoming trip to Iceland. I took it home, charged the batteries, named it "Dumbo", registered with the FAA, and, following along with the DJI preflight checklist videos, updated the firmware and setup the DJI Go App. Anxious, I took the drone up to my roof in order to calibrate the compass and perform my first flight in beginner mode; my goal was to do a simple take-off, 360 degree yaw rotation and land. After the compass successfully calibratated, I checked for solid GPS/Satellite numbers and nervously did my first auto-take off. I was exhilirated when the bird lifted off. After hovering and staying perfectly stable for about 15 seconds I performed a slow rotation and began taking video; no problem here. I continued to let the drone hover for about another 10 seconds at which point it started behaving slightly erratic. It began drifting backwards and increasing in elevation. Nervous, I hit the return to home button, expecting it to adhere to the RTH parameters in the DJI Go app and return to the home point. At this moment, the Phantom shot out in front of me and performed a long sweeping arc, increasing in speed, elevation, distance before ultimately swinging around my apartment building and smashing on the neighboring buildings roof. I was able to recover the destroyed drone the next day.

Details:
1 - Took drone to isolated roof for simple take-off/landing test away from people.
2 - Kept drone in beginner mode
3 - Successfully calibrated compass
4 - Had strong Satellite/GPS signal at takeoff
5 - Drone began drifting and increasing in elevation
6 - Hit the 'Return to Home' button
7 - Phantom exited the maximum altitude/distance settings
8 - Phantom smashed into neighboring roof

So, what happened?
Are these the tell tale signs of a compass error? Did I funk up?
Was my drone funked up?
Do I have any recourse to recoup any of my Phantom 4?

Flight log:



Available flight video (from video cache):
https://drive.google.com/open?id=0B764lG2inXoFOWFOS1p4cktqOTQ

Thanks for any insights or suggestions you can provide!

Justin

can you post a video of the log playback with the sticks overlayed ( prss the button to showe stick inputs)

Sure thing, here's the video flight log:

https://drive.google.com/open?id=0B764lG2inXoFOVpaZlhvOGNudms

Sad to say, but even without looking at the logs, the first thing that stands out is that you say you performed the compass calibration on the roof of the building, and that is a bad start.

The compass calibration must be done in an area well away from concrete, building and any form of steel or iron work, and your building would have been full of steelwork.

I don't know about your drone but I do know the moderators do take to kindly to you using the f-word like a comma.

Upload your log file from your  mobile device that you used to control the drone to see what actually happened

http://www.phantomhelp.com/LogViewer/Upload/

Mattd, here's that log: http://www.phantomhelp.com/LogViewer/Z3MXWWUJUEGNVMFAGB31/

Thanks for your help!

R&L Aerial  Posted at 2016-4-25 18:06
I don't know about your drone but I do know the moderators do take to kindly to you using the f-word ...

Sorry about that.

Yep the roof thing is it.
Even listening to the description of the Phantoms behavior it sounds like a bad compass cal.  

Geebax Posted at 2016-4-25 18:06
Sad to say, but even without looking at the logs, the first thing that stands out is that you say yo ...

Thanks for taking the time to respond.

I didn't see anything about that in the setup or preflight checklist. When I performed my compass calibration it succeeded. Should the app have told me other otherwise?

Drone Man Posted at 2016-4-25 18:23
Yep the roof thing is it.
Even listening to the description of the Phantoms behavior it sounds like  ...

Rats. I didn't see anything in the documentation or the DJI videos about where to calibrate compass. And it seemed to calibrate fine.

Appreciate everyone's help. Anything discernible from the logs?

Whilst this does look like TBE I don't like it one bit, not a single compass error, also remember the P4 has duel compass so these kinds of things should not happen, calibrating on the roof that may of contained a lot of steel could have thrown the compasses but he should have had errors or it switch to the other compass or even P-ATTI
I'd like DJI to look over those logs as I see nothing you have done to cause that.

Mad_Angler1 Posted at 2016-4-26 08:59
Whilst this does look like TBE I don't like it one bit, not a single compass error, also remember th ...

The dual compass does not protect against that sort of thing. If the calibration is influenced by steelwork, it will influence both compasses. The flight path looks remarkably like a spiral out from the centre, which would be the possible outcome of a compass malfunction.

Mad_Angler1 Posted at 2016-4-25 18:59
Whilst this does look like TBE I don't like it one bit, not a single compass error, also remember th ...

Thanks for your insights. How would I go about having DJI officially look over the logs?

This is from the manual;
"Do not calibrate your compass where there is any possibility of strong magnetic interference.
Sources of potential interference include magnetite, parking structures, and subterranean
metal structures
Do not carry ferromagnetic materials with you during calibration such as keys or cellular
phones.
Do not calibrate in direct proximity to large metal objects.
DO NOT calibrate indoors."
"Only fly in open areas. Tall structures and large metal structures may affect the accuracy of the onboard
compass and GPS system."

Did you have the VPS turned on out of interest ?

yogi

yogi Posted at 2016-4-26 07:16
Did you have the VPS turned on out of interest ?

yogi

VPS cannot be turned off on the P4.

Drone Man Posted at 2016-4-25 19:15
This is from the manual;
"Do not calibrate your compass where there is any possibility of strong mag ...

Very relevant, thanks for flagging. So I goofed big time doing my initial compass calibration on the roof huh? Shouldn't the compass calibration have failed?

yogi Posted at 2016-4-25 19:16
Did you have the VPS turned on out of interest ?

yogi

Made no changes to VPS.

walrus123 Posted at 2016-4-26 07:29
Very relevant, thanks for flagging. So I goofed big time doing my initial compass calibration on th ...

Sorry Justin, looks like you goofed big time.
A hard lesson learned,
I feel for ya buddy  

Drone Man Posted at 2016-4-25 19:33
Sorry Justin, looks like you goofed big time.
A hard lesson learned,
I feel for ya buddy

For future reference, I've seen loads of videos in which people are flying Phantoms in urban environments, taking off from their roofs. In these cases, were they calibrating their compass elsewhere before taking to the roof?

R&L Aerial  Posted at 2016-4-25 15:06
I don't know about your drone but I do know the moderators do take to kindly to you using the f-word ...

DO take TOO kindly? Well phuk
Your post is about as worthless as me making a worthless post to say it's worthless
Go to http://www.phantompilots.com/ . Their admins like worthless stuff

1. Compass should be done at ground level.2. RTH minimal distance to press 20 mts.
Sorry for your lost.

walrus123 Posted at 2016-4-26 07:42
For future reference, I've seen loads of videos in which people are flying Phantoms in urban envir ...

My buddy in San Jose Ca. has flown from roof top many times but the compass cal was done at ground level in a football field.
Compass cal on a roof top is a no,no.

walrus123 Posted at 2016-4-26 09:29
Very relevant, thanks for flagging. So I goofed big time doing my initial compass calibration on th ...

'Shouldn't the compass calibration have failed?'

No, because that is what the compass calibration is designed to do, take care magnetic anomalies in the region you are flying. It would have made adjustments for all the metal around it, then when it got in the air, it would have discovered that the magnetic properties were quite different.

Drone Man Posted at 2016-4-25 21:10
My buddy in San Jose Ca. has flown from roof top many times but the compass cal was done at ground ...

Well crap. But good to know if I decided to buy another Phantom. Thanks!

Geebax Posted at 2016-4-25 18:09
The dual compass does not protect against that sort of thing. If the calibration is influenced by  ...

That was my impression as well.

Geebax Posted at 2016-4-25 20:21
'Shouldn't the compass calibration have failed?'

No, because that is what the compass calibration ...

Thank you for saying that so I didn't have to. It worked as it should have.

I guess at this point I should start thinking about recouping some money. Is it worth sending to DJI if the damage is extensive? If not, I have a brand new battery, controller and extra set of blades. Is there a market for selling the useable Phantom 4 parts?

That really sucks and I am sorry. I wish they included a manual with the Phantom (instead of expecting you to download it). My first Phantom was a Phantom 1 and I ruined it with a month (by using the screws that came with the prop guards after I had removed the prop guards. The good news: You think you just lost $1500. The slightly better news: Probably more like $1100. A local flyer crashed his and just sold the remote on eBay for $400 (as far as I know DJI is not seeking them yet). He had it listed as "Buy it Now" for $400. It was only up a few days. Your luck may vary. Again, sorry for your loss.

Sorry for yours lost. I crashed my phantom 4 too.

madaerial Posted at 2016-4-25 21:46
That really sucks and I am sorry. I wish they included a manual with the Phantom (instead of expecti ...

Appreciate that! I really did think that I'd covered all my bases by going through the DJI Phantom 4 setup video guide. Expensive lesson in RTFM. And thanks for the tips on selling. I'll get some stuff up on eBay and see if I can recoup some of the cost in preparation from "Dumbo II - The Revenge".

Expensive lesson, but after you buy another you probably will not make that mistake again.

I would be pleasantly surprised (if not a bit shocked) if DJI gave a warranty on this one but keep us posted.

Sorry for you loss
Very strange storie
When you hit RTH, as you was less then 20 m front Dumbo, it should land
I have already seen videos of phantom drifting because of the error in the compass, but with the message of "CAMPASS ERROR" in the DJI GO
P4 is very new with a new tecnology of 2 compass, maybe this could be a bug not solved yet,  it's dificult to say

What mode where you flying in?

mattd Posted at 2016-4-25 22:40
What mode where you flying in?

I was in Position with Beginner Mode enabled.

Cessna172 Posted at 2016-4-25 22:36
Expensive lesson, but after you buy another you probably will not make that mistake again.

I would  ...

Will do! Thanks for the support.

Justin,

First - I'm very sorry that you had such a bad first flight experience. I feel for you. I crashed my very expensive DJI Inspire 1 on my first day of flying it a year ago. So, I can honestly say, I know how you feel.

COMMENTS:  First, here's what you did RIGHT! You had Beginner Mode turned ON for your first flight (smart!).  You made no wild stick moves - in fact, just the opposite. You made very reasonable and controlled movements consisting of small incremental increases in elevation to 9.8 feet and then 13-16 feet, and then to 36 feet and two partial turns with less than 50% stick.  And - you knew about (and at least attempted) to execute a Return to Home (RTH) by pressing the RTH button when the P4 started drifting away from you in a spiral. (NOTE: you have to PRESS and HOLD the RTH button on the remote controller for several seconds until it remains illuminated and starts BEEPING continuously.)  Finally, you are reaching out to other forum members for input and analysis and respectfully acknowledging that input instead of lashing out at DJI. You want to know what might have happened and what you might have done better/differently -- I commend you for that.

Here's what you could have done better/smarter:  You picked a particularly bad location for a first flight - on top of a xx-story building in a very urban, busy area near other multi-story buildings and an elevated freeway. It would have been much safer and a much more controlled environment if you had chosen a clear, open field with no trees or other nearby obstructions or people for your first dozen or so flights. I can honestly say that I would hesitate to launch any of my aircraft from the location you chose - even with a year of flying experience on multiple DJI aircraft.

My Non-Expert (and possibly incorrect) Analysis:

I have reviewed your flight log and the partial video you recovered. Based on only that information, I don't think this was a compass calibration error. I don't claim to be an expert, but I have been flying multiple DJI quadcopters for over a year and I have dealt with failed compass calibrations, which you clearly did not experience (calibration succeeded), and I have experienced "compass calibration errors" caused by calibrating and then taking off from rebar-reinforced concrete structures (driveways, parking lots, even an 8-foot-diameter concrete helipad at my local model airplane park).  

Although calibrating your P4 on top of a concrete and/or steel-reinforced building certainly COULD have caused a compass calibration error - as noted by several other forum members, I don't think that's what happened in your case.  WHY?  In my experience a compass calibration error presents itself as an almost immediate drifting after take-off and is often accompanied (though not always) with a "Compass Error" warning message on the DJI GO app.  That did NOT occur in your case.

In your documented flight, you rose to 9.8 feet, executed a 180-degree turn, then rose to 16 feet, made a second 240-degree turn - all with less than 1 foot of drift from Home point as recorded on the flight log.  It was only when you started ascending a third time and reached ~36 feet above the rooftop that you launched from that the P4 started spiraling away from you. And again, the P4 had essentially zero drift from home point as you were ascending UNTIL you reached 36 or so feet (above the rooftop).  

Based on the satellite image in your flight and the partial video you were able to salvage - you were in a very urban area with possibly other apartment buildings and commercial structures surrounding your launch location. Many of these buildings (including your own) often have satellite dishes, microwave transmitters, cellular phone repeaters and other high-power radio frequency transmitters/receivers.  My best guess is that when you reached 36 feet elevation above the roof of the already elevated structure you launched from - your P4 was hit with very strong radio-frequency interference from one or more nearby sources.  Another possibility is that a nearby taller concrete and steel building or the freeway interfered with / reflected one or more of the GPS satellite signals that your P4 was currently locked onto.

ADVICE: Since you recovered your crashed P4 you can extract the detailed flight log .DAT file from the internal memory (not the micro SD car) inside the P4 aircraft using a USB cable and a laptop PC (search for instructions on this forum on how to do this) and then send this .DAT file to DJI for analysis.  They can examine this .DAT file in detail and possibly identify exactly what one or more things likely caused the spiral drift behavior.

Finally, please take this a very painful, but valuable, lesson learned (like I did with my Inspire crash a year ago). My guess is that DJI will at least offer you a discount on a replacement aircraft. And, your damaged aircraft may be repairable for much less than the cost of the new P4.  At the very least, you still have a perfectly good $400 transmitter.

My best wishes for a much more positive experience on your second flight with a new or repaired aircraft, whenever that might be.

Kind regards,

- Dave