I was flying my shiny new Phantom 4 (just upgraded from my Phantom 1.1.1 that I've been flying for the last 2 years) and I was hovering at ~250ft. I went to decend, so I put the left stick down (to 100%) and the motors shut down (just like they would if it were on the ground). This is disturbing behavior since the manual doesn't say anything about the left stick at 100% down causing a CSC mid-flight (as opposed to the Left stick to the bottom right and hitting RTH). The entire flight was 49 seconds.
I replayed the flight in the DJI Go app and the only thing I did was pull the left stick down. The signal was solid, I had GPS lock, etc.

The drone is now wrecked: camera sheared off, skids are busted, body damage. It just beeps when you power it on (ESC error) and I'm waiting to hear back from support on what the repair will cost me.

Has anyone else had a Phantom 4 fall out of the sky due to the motors cutting off when decending?

I'm attaching my flight log if anyone wants to re-live my horrible flight.

http://www.healthydrones.com/mai ... &page_id=GENERA
I went ahead and uploaded your log. I'm attempting to figure things out.

"Has anyone else had a Phantom 4 fall out of the sky due to the motors cutting off when descending ? "

You are right in what you say, left stick down shouldn't shut off the motors, and doesn't on my machine. There is not much information to work off of in healthy drones. Certainly no record of the engine shutting down. I wonder if the battery came loose ?

Aardvark Posted at 2016-8-30 01:36
"Has anyone else had a Phantom 4 fall out of the sky due to the motors cutting off when descending ? ...

I doubt the battery came loose during the flight because it was in P-mode and just hovering. Interestingly, after impact, the props were still twitching, so the battery didn't even pop out after impact.

I'm hoping this is ruled a hardware or software failure and DJI will replace my unit for little-to-no cost. The $1400 hit to replace it is just too much for me to foot the bill after saving up for this for so long.

Aardvark Posted at 2016-8-30 01:36
"Has anyone else had a Phantom 4 fall out of the sky due to the motors cutting off when descending ? ...

A P4 will NOT shut down unless there was a CSC or the battery was not locked in.

Maximillian Posted at 2016-8-30 01:43
I doubt the battery came loose during the flight because it was in P-mode and just hovering. Inter ...

I'm sorry for your crash.
What is your DJI login email and I will look at your flight.
The only way a P4 will shut down is from a CSC or the battery wasn't fully inserted and locked in.

DJI-Ken Posted at 2016-8-30 02:14
I'm sorry for your crash.
What is your DJI login email and I will look at your flight.
The only way  ...

Hey Ken, is there no private message system on this forum?

I submitted my flight log to support.us@dji for analysis like the online chat told me to.
EDIT: Also, the battery couldn't have disconnected because I have video of the entire flight including the crash. Had the battery disconnected, the video would have stopped/been corrupted (unless the Phantom is magical).

Maximillian Posted at 2016-8-30 02:21
Hey Ken, is there no private message system on this forum?

I submitted my flight log to support.us ...

Ij would love to see thatg video.

DJI-Ken Posted at 2016-8-29 19:13
A P4 will NOT shut down unless there was a CSC or the battery was not locked in.

And strictly speaking a 'CSC' command will not shut down the motors on a P4 in flight.

But a left stick down to the right and a stuck RTH button might (just a thought).

Update!

DJI is saying that the gimbal guard (plastic piece installed across the bottom of the landing skids to prevent damage to the gimbal in the event of a minor crash) interfered with the sensors and that makes it my fault so they will not cover any of the cost. So that's a bummer.

Maximillian Posted at 2016-8-30 02:21
Hey Ken, is there no private message system on this forum?

I submitted my flight log to support.us ...

That sounds like a CSC then.
We do not have PMs.
The easy way to tell is to playback the flight record yourself. Enable the stick overlay and you can see if you did a CSC when the motots stopped.

Aardvark Posted at 2016-8-30 03:04
And strictly speaking a 'CSC' command will not shut down the motors on a P4 in flight.

But a left  ...

Technically you are correct, although we still call it a CSC.
But that means "combination stick command" and I guess since your not using a combination of sticks you are correct

What I am trying to say is that the term CSC is loosely used to describe a motor shut down for a P4 when in flight. Nowhere in the manual does it refer to the motor shut down in flight for a P4 as being a Combined Stick Command. Although the Combination of two sticks is used to start, and can be used to stop the motors when on the ground.
It might seem a bit pedantic but the term does confuse some of the newer Phantom 4 Pilots.

Sorry for your loss.

Did the P4 do an ascent on it's own?  or did you fly it up and then hover?

So the P4 thought it was on the ground because of the guard!  so when you pressed the left stick down, it stopped the motors.

I am a bit confused though; doesn't take into consideration the gps reading though?  I thought that is the primary sensor. The last altitude shown in the log is 227 feet.  Why should it copmute it to be ground level?
Maybe ask them to look into it further.

Maximillian Posted at 2016-8-29 21:38
Update!

DJI is saying that the gimbal guard (plastic piece installed across the bottom of the landi ...

Sorry for your crash but this makes sense: if your gimbalguard interferes with the downward sensors AND you pull the left stick 100 % down then the AC will check if it can descend further, gets the message that it can't because the gimbal guard is 'seen' as the ground and it shuts down the motors.
So, yes, I can understand DJI's point of view. There have been several warnings about these gimbal guards in various threads.

i've definitely seen YouTube videos where users have weird issues when having the gimbal guard on. NO one should be using that guard, which interferes with the sensors that face downward. This is what likely happened here in some form.

If that is a metal table, I would not use it to take off from.  Compass does not like it.  

sunny051488 Posted at 2016-8-30 04:18
i've definitely seen YouTube videos where users have weird issues when having the gimbal guard on. N ...

I wish I'd seen warnings about the gimbal guard. I did some research before purchasing my Phantom 4 and saw a few people recommend a guard, so I figured it was a reasonable $20 accessory. It makes sense that the VPS thought it was lose to the ground (if it was detecting the guard), but it's still disappointing to have crashed this way. Once I've repaired it, I certainly won't replace the guard (which was lost in the crash anyway).

Maximillian Posted at 2016-8-29 21:47
I wish I'd seen warnings about the gimbal guard. I did some research before purchasing my Phantom  ...

It's a tough one Maximillian, DJI might be able to repair at reasonable cost though.

Maximillian Posted at 2016-8-29 16:47
I wish I'd seen warnings about the gimbal guard. I did some research before purchasing my Phantom  ...

Sorry again!  I use a guard when I carry the P4 in the bag but I have BIG red letters on it "TAKE ME OFF"

So is the idea that the drone was thinking it has landed, because the VPS was looking at the protector, hence with the left stick down it just shutdown the motors and fell?

Aardvark Posted at 2016-8-30 04:52
It's a tough one Maximillian, DJI might be able to repair at reasonable cost though.

I'm wary of sending it in without knowing the cost up front vs just fixing it myself. I installed a gimbal on my Phantom 1.1.1 which required replacing some internals, so I'm comfortable getting my hands dirty.

I've also been reading horror stories about DJI taking 8+ weeks to repair and return units, which is a long time to be without flight.

I may open the shell and see if either of the ESC boards is damaged, and if not, I'll just replace the camera/skids myself (no soldering required as I understand).

Thanks for all the help everyone!

Phantomski Posted at 2016-8-29 17:00
So is the idea that the drone was thinking it has landed, because the VPS was looking at the protect ...

I think so.  It computed the altitude to be ground level!  I am glad it is not reading the camera position.
I am still questioning though that the last altitude reading was correct in the logs; did the processor think it went from 227 to 0?

Maximillian Posted at 2016-8-30 05:02
I'm wary of sending it in without knowing the cost up front vs just fixing it myself. I installed  ...

DJi will evaluate it and if you don't agree to the repair cost then they will send it back to you un-repaired.
DJI turn around time is 1-2 weeks from when it's check in here.
The Phantom4 is nothing at all like a P3, doing self repairs on a P4 is extremely difficult.
I'm sorry that it happened to be a gimbal guard, usually a gimbal guard will make the aircraft yoyo up and down tens or even hundreds of feet and not cause the motors to quit unless it though it landed when it was at 250ft and came falling down.
Did you playback the flight record to see the stick movements or warning messages at that moment?

Phantomski Posted at 2016-8-29 22:00
So is the idea that the drone was thinking it has landed, because the VPS was looking at the protect ...

My only thought would be that the barometer would still be registering a downward movement. I wonder if it needs the DJI Techs to examine the flight records to be sure of cause ?

DJI-Ken Posted at 2016-8-30 05:17
DJi will evaluate it and if you don't agree to the repair cost then they will send it back to you  ...

I played the flight record and the only thing that happened in the last 10 seconds was me pulling the left stick down 100%. No warnings or anything else that would explain the cause.

I'm still not sure that the 1-2 weeks without my bird is worth it if I could just replace what's broken (for cheaper, too, since I don't have to pay myself labor). I'm not sure why the P4 would be hard to self-repair. At worst, it's some soldering. At best, it's just screws and plugging in some cables.

As for the gimbal guard, it didn't affect any of the flights I've done (multiple miles over open water). I didn't get any yoyoing or have any issues landing so it was kind of shocking that this happened.

Maximillian Posted at 2016-8-30 05:58
I played the flight record and the only thing that happened in the last 10 seconds was me pulling  ...

Can you get the DAT file from the last flight (from the Assistant2 software) then upload the file to Dropbox or something like that and I will have the log analyzed.
Add the link to your ticket or post it here and I'll get it analyzed tomorrow.
I too want to know what exactly it was.

Sorry for your loss, but it would have been good to mention in the first post that there was a modification or non standard accessory fitted to the bird.

Most do not consider a guard bar as modification, and most do not think it would have any impact on the bird.. DJI on the other hand dislikes ANYTHING non DJI on their birds... so between finding middle ground and figuring out if something actually could make a difference, it's all a bit weird.. I would not consider that a "modification" if I didn't read a post on that specific issue and did not ping DJI a bit deeper to see what they say about almost ANY non DJI accessories.
I would agree with DJI-Ken, that it's worth looking at the DAT file with him or support... If it was caused by the accessory, it would suck, but would be good to confirm.. If it was not caused by the accessory, then perhaps DJI will help better to get it fixed, and the warranty will be intact? Always worth a try.

MD_Icarus Posted at 2016-8-29 16:11
Sorry for your loss.

Did the P4 do an ascent on it's own?  or did you fly it up and then hover?

Hi, it doesn't take into consideration of GPS when landing. Because it's common if you're, say climbing a hill and operating the drone at the same time, when you reach the top of the hill, you want it to land where you are, so the drone lands somewhere higher than where it takes off.

http://forum.dji.com/thread-53496-1-1.html  There was actually a notice about this in May this year, the notice was pinned on the top of the forum for about 30 days.  OP probably wasn't there when the notice was posted. Sorry about your experience.

Maximillian Posted at 2016-8-29 15:38
Update!

DJI is saying that the gimbal guard (plastic piece installed across the bottom of the landi ...

That's B.S.
I've flown with a gimbal guard since day 1. (over 300 flights)
And I've never experienced what you've described.

Some gimbal guards might  block the sensors while others may not...

What is interesting to me is that if one places the guard properly under the camera, then the VPS can not actually "see" it because the gimbal is between the sensor and the guard.

I always play it safe though, and I only use a guard when the P4 is in a backback.  Some though like to use it to protect the camera in the event of an abrupt landing.  I always catch the P4 tough, I never let it land.

MD_Icarus Posted at 2016-8-30 21:52
What is interesting to me is that if one places the guard properly under the camera, then the VPS ca ...

A guard placed directly under the camera is much better than placing it under the rear. But then you cannot look straight down.
Also, the guard does not have to be directly under the VPS to cause an issue. The sonar waves radiate out so even if it was a few inches in front of the VPS it may or may not cause an issue.

Phantomski Posted at 2016-8-30 12:24
Most do not consider a guard bar as modification, and most do not think it would have any impact on  ...

When the DAT file gets analyzed we'll know for sure  what happened.
Normally when you touch down, you close the throttle and after 3 seconds the motors shut off because the sensors know it's on the ground. If the sonar was reading ground level because of the guard then after 3 seconds the motors would shut off.

Maximillian Posted at 2016-8-30 05:58
I played the flight record and the only thing that happened in the last 10 seconds was me pulling  ...

Did you upload the DAT file of the flight to your ticket?
What is the ticket# ?

scarzee@hotmail Posted at 2016-8-30 06:15
Sorry for your loss, but it would have been good to mention in the first post that there was a modif ...

I agree, the OP should state Possibly from attached gimbal guard.

In some other threads about mounting the Trackimo device, we talked some about placing the gps unit on "a gimbal guard".  My thought was to make my own (I'm well versed in CAD and CNC...) and move the guard fore or aft trying to stay away from sensors as much as possible.  I am curious though what the divergence of the beam is on the sonar sensors and the cameras but I doubt we'll ever get that info.

Scratch that whole idea and mount the gps to one of the legs or stick it on the face of the battery each time.  No reason to leave anything to question on accessories and liabilities.

Sorry to hear about your crash!

DJI-Ken Posted at 2016-8-30 22:09
Did you upload the DAT file of the flight to your ticket?
What is the ticket# ?

Hey Ken,
When I go to get the DAT file, it never loads the list of files (in the Assistant software). I tried on a Mac and a PC and left it thinking for 5-10 minutes without success.

Also, the Phantom is just beeping (from the motors) when it's powered on. Is there a way to reset it in order to stop the beeping? When I connect it to the DJIGo app, it finds a GPS lock and says "Safe to Fly" but the motors won't power on.