fansfcb70189 Posted at 2017-5-23 09:52
ok so i just checked my logs from another flight(without landing gear)....  it also shows that vps is 0ft when im at high altitude.  so why when i pressed down on the left stick did it not shut down? can anyone please confirm this on their drone logs?

Can you also post that log on PhantomHelp for us to have a look?

Nigel_ Posted at 2017-5-23 11:55
Can you also post that log on PhantomHelp for us to have a look?

with landing gear http://www.phantomhelp.com/logviewer/P7EBM0MXKJ71LQ6N6FVF/
Without landing gear  http://www.phantomhelp.com/logviewer/9G5M59D74RZB4YYYPOMQ/

Is there someone here i can send my .dat file to from DJI to look into what happened while i wait for my shipping label and possibly tell me in advance if its covered under warranty?

fansfcb70189 Posted at 2017-5-23 12:43
with landing gear http://www.phantomhelp.com/logviewer/P7EBM0MXKJ71LQ6N6FVF/
Without landing gear  http://www.phantomhelp.com/logviewer/9G5M59D74RZB4YYYPOMQ/

The ultrasonic sensors are working fine in both those logs.

Maybe you positioned the extensions a little differently?

Could be that your ultrasonic sensors have failed, but this isn't a problem we see often so I think it is highly likely due to the extensions.

You could ask your contact at DJI support if they could analyse the dat file first, although I think there is enough info in the phone log you have already given them via syncing.

Are you using an old aircraft firmware?   We had several incidents like this with early firmwares using gimbal guards but we haven't seen any recently so I thought they had added some safeguards in the firmware...

Nigel_ Posted at 2017-5-23 16:07
The ultrasonic sensors are working fine in both those logs.

Maybe you positioned the extensions a little differently?

Newest firmware...  what I want to know is when the aircraft is at say 30m in the other logs the vps shows 0 .. so why would it not shut down the motors then when down is pressed?  When my flight I understand said mostly 0 the whole time on vps why when at a 240m when I pressed down it shut off ?  If that is the potential issue.

fansfcb70189 Posted at 2017-5-23 16:14
Newest firmware...  what I want to know is when the aircraft is at say 30m in the other logs the vps shows 0 .. so why would it not shut down the motors then when down is pressed?  When my flight I understand said mostly 0 the whole time on vps why when at a 240m when I pressed down it shut off ?  If that is the potential issue.

The value 0 is used for both "zero height above ground" and "out of range", there is a separate value in the log which says which it is, in the last two logs you posted the out of range becomes true whenever the barometer shows over 15m, in the log from the crash the out of range is false most of the time, including when it was making the decision to turn off the motors.   So it couldn't tell the difference between being 248m above the ground and you having flown up a very steep cliff and still being 0m above ground even though you were at 248m above take off.

I am fairly sure it decided to end the flight due to the power consumption dropping to idle in the last second.

Whatever DJI decide, I strongly suggest that you don't fit those extensions to your next aircraft, modifying aircraft in any way is risky and can lead to unexpected problems, such as fatigue cracks resulting from changes in the vibration characteristics.  I would also inform the seller/manufacturer so that hopefully other people don't have the same experience.  If DJI confirm that it was the extensions causing the problem then you might want to try claiming compensation off the extension seller/manufacturer, that might at least get them removed from sale.

Nigel_ Posted at 2017-5-23 23:40
The value 0 is used for both "zero height above ground" and "out of range", there is a separate value in the log which says which it is, in the last two logs you posted the out of range becomes true whenever the barometer shows over 15m, in the log from the crash the out of range is false most of the time, including when it was making the decision to turn off the motors.   So it couldn't tell the difference between being 248m above the ground and you having flown up a very steep cliff and still being 0m above ground even though you were at 248m above take off.

I am fairly sure it decided to end the flight due to the power consumption dropping to idle in the last second.

Thank you all for your patients and explanations you are all very informative and knowledgable. I respect all your input. I'm going to send it in and hope for the best. Hopefully DJI will replace it. I love my phantom and babied it since day one. I will post a follow up once I get it sent over to them.

Maybe there is a hidden flight mode K for "Kamakaze"  Sorry for your loss! I hope u get a new one soon!

Mabou2 Posted at 2017-5-23 03:28
The P4 flipped in its own prop wash vortex as it was descending.  Early on after I got my P4, I had one experience where my P4 bucked really hard while descending quickly.  We all know that the P4 has a rough ride while descending and our video footage reveals this.  Turns out this is a somewhat known possibility for any drone.   The prop wash creates havoc in the air, when the drone is descending, it is constantly dropping into its own unstable chaos.... add the side wind from an abrupt gust and your drone could flip.  Now I make sure to move in a slow crawl forward while descending quickly.

it actually works against us that this problem isn't more widespread.  If this problem wasn't so rare, DJI would find a way (whether using its existing sensors or adding a new sensor) to know if the drone had inverted and could program a rapid auto-response for the drone to right itself (for example, by briefly killing power to the props on one side of the craft, causing the drone to flip back from being inverted).

Good Point!

Labroides Posted at 2017-5-23 06:13
"Question in support of the data... does the data show what the status of the motors were at any given point? "

This data is in the internal memory of the Phantom and is part of the big picture that DJI will be able to extract.

Maybe taking a portable trampoline ,might help in future!

fansb0844b03 Posted at 2017-5-24 05:15
Maybe taking a portable trampoline ,might help in future!

Interesting thread to read through.  I only have the P3S and not extensions on the drone, just an Argtek Antenna.  

Your video was pretty scary.  Let's see what DJI have to say.

blackcrusader Posted at 2017-5-22 18:58
I guess this is one for  DJI nothing in the flight log I can see.  I fly in remote areas and try to stay away from people houses etc when I can.  

PS I guess you are up to date on drone laws in Canada.   Might not want everyone to see your video.

Agreed. Although I am not one to necessarily follow the letter of the law, especially with the unreasonable laws in Canada, however, 240M is a height that you could easily end up in conflict with manned aircraft as they are allowed to fly quite a bit lower than that in rural areas. Please don't do that. It affects us all.

Sorry about the bird.

fansfcb70189 Posted at 2017-5-24 02:57
Thank you all for your patients and explanations you are all very informative and knowledgable. I respect all your input. I'm going to send it in and hope for the best. Hopefully DJI will replace it. I love my phantom and babied it since day one. I will post a follow up once I get it sent over to them.

I don't know if this will help you at all but I did a little math exercise to determine if your theory that the motors were running when it hit was valid. In short, an object falling from a height of 807.7 feet weighing 1.38 ( the stated weight of the P4 is 1380 grams) grams in free fall will take a little over 7 seconds to hit the ground.  Your video ends at 1:57 minutes and the first indication of trouble shows up at 1:48. Clearly the motors weren't powering the P4 down or the fall time would have been faster.  The speed at impact would have been about 250 km/hr. Good luck!

PartsGuy Posted at 2017-5-24 14:12
I don't know if this will help you at all but I did a little math exercise to determine if your theory that the motors were running when it hit was valid. In short, an object falling from a height of 807.7 feet weighing 1.38 ( the stated weight of the P4 is 1380 grams) grams in free fall will take a little over 7 seconds to hit the ground.  Your video ends at 1:57 minutes and the first indication of trouble shows up at 1:48. Clearly the motors weren't powering the P4 down or the fall time would have been faster.  The speed at impact would have been about 250 km/hr. Good luck!

That arithmetic would only work for an object with no wind resistance and the Phantom has significant wind resistance which varies with the position of the Phantom (which often varies).
Terminal speed of a falling Phantom oscillates around 35 mph.
It takes about 80 metres and 6 seconds to reach terminal velocity so for this case the time to the ground would have been around 16 seconds.

Capo Posted at 2017-5-24 12:39
Agreed. Although I am not one to necessarily follow the letter of the law, especially with the unreasonable laws in Canada, however, 240M is a height that you could easily end up in conflict with manned aircraft as they are allowed to fly quite a bit lower than that in rural areas. Please don't do that. It affects us all.

Sorry about the bird.

No commercial or civilian aircraft allowed where I live Private planes are not allowed in Taiwan. Sometimes I need to climb 400m through the clouds to altitudes above 11000 feet to get my videos.  I could imagine some of the stunning scenery that Canada would have having seen some fantastic pictures taken there.

blackcrusader Posted at 2017-5-24 17:30
No commercial or civilian aircraft allowed where I live  Private planes are not allowed in Taiwan. Sometimes I need to climb 400m through the clouds to altitudes above 11000 feet to get my videos.  I could imagine some of the stunning scenery that Canada would have having seen some fantastic pictures taken there.

No commercial or civilian aircraft are allowed, but drones are, and no private planes in Taiwan? Wow... Droner's paradise there.

In Canada, we'd better not be spotted above 90 meters or above cloud or at night among many other ridiculous restrictions or we can get a $3000 fine.

In fact, our government has gone as far asking snitches to call 911 with reports of drones. What a waste of the 911 operator's time!

Labroides Posted at 2017-5-24 15:15
That arithmetic would only work for an object with no wind resistance and the Phantom has significant wind resistance which varies with the position of the Phantom (which often varies).
Terminal speed of a falling Phantom oscillates around 35 mph.
It takes about 80 metres and 6 seconds to reach terminal velocity so for this case the time to the ground would have been around 16 seconds.

That is when it is the correct way up, it is going to be a fair bit faster when upside down, the top surface is aerodynamically quite slippery compared to the bottom and the props will have less drag when turning the correct direction.  Although there was a little extra drag from the extensions.

I'm a bit surprised it got down quite so fast but I still think the motors where powered off.

You're going to be the first person in Ontario slapped with a $3,000 fine and you deserve it.

He wrote... "press down on the left stick for maybe 3 secconds."... this cause motor-stop....

Bluesphere Posted at 2017-5-25 12:18
He wrote... "press down on the left stick for maybe 3 secconds."... this cause motor-stop....

Full left stick down does not shut off motors unless the drone has landed.

I often do full left stick down from 500m height when bringing my drone home.

Nigel_ Posted at 2017-5-25 09:58
That is when it is the correct way up, it is going to be a fair bit faster when upside down, the top surface is aerodynamically quite slippery compared to the bottom and the props will have less drag when turning the correct direction.  Although there was a little extra drag from the extensions.

I'm a bit surprised it got down quite so fast but I still think the motors where powered off.

I agree. Although I did not factor in volume, I sill think that the fall time does not bear out a powered  descent based on the video. The op doesn't say if the battery was ejected on impact. It could have come loose and disconnected during the flight. It will be interesting to see what DJI has to say.  

PartsGuy Posted at 2017-5-26 16:41
I agree. Although I did not factor in volume, I sill think that the fall time does not bear out a powered  descent based on the video. The op doesn't say if the battery was ejected on impact. It could have come loose and disconnected during the flight. It will be interesting to see what DJI has to say.

'The op doesn't say if the battery was ejected on impact. It could have come loose and disconnected during the flight. It will be interesting to see what DJI has to say.  '

Did not happen. The camera was working all the way down and even while it was lying there after impact.

Fan, Yes  I can understand what you are trying to convince everyone else of.  My Phantom 4 also performed about the same thing.  It flipped at about 200 feet and flew upside down into soft ground and leaves.  I saw it "falling" fast and applied more power, not knowing it was upside down.  That only increased the descent.  My P4 landed upside down, broke all 4 props and damaged the gimbal plus denting two of the arms.  Mine also did not record data to the internal card because DJI denied this ever happened because they said that no flight records were on the drone!  And YES, I was supposed to have submitted flight data logs with the drone when I sent it in for repair!  Who knows this???  I never heard of such a thing.  Anyway, I researched my crash as much as I could and found out that a Phantom 4 does not flip over-it will right itself almost immediately.  I challenged DJI to cause a Phantom to flip and fly upside down into the ground (or net) and they never admitted either way.  I fought with DJI customer service for a month and accumulated about 2 inches of printed emails from them, where they never answered a single question I sent.  They always avoided the answer, leading on to some other situation.  Strange though, after I paid the $239 repair bill, they sent me a new Phantom but they somehow "forgot" to provide the four springs that apply tension to the propellers!  It took me only seven weeks to finally get them!  DJI NEVER EXPLAINED WHAT HAPPENED!  They never admitted fault or warranty issue.  DJI customer service lied to me on almost every occasion.  They had two different "reps" tell me two different stories at almost the same time.  The Phantom that flipped, actually was still powered on and flyable after falling some 200 feet.  I have cell phone video of it laying on its broken propellers with 3 green LED's on and one blinking.  The lights were still on and the cell phone audio picked up the telementry being still transmitted.  I almost immediately cleaned the mud off, applied new props, and it flew!  Everything worked except the gimbal, which stuck at one spot.  Video was perfect and the drone flew several test flights before being sent to DJI.  There was no video recorded of the flip and crash, none on my iPad, none on the SD card, and according to DJI, none on the internal card, however one representative who claimed to be a supervisor told me on the phone that the video on the internal card showed it was not a warranty issue!!!  Go figure!!!  I got on two different forums, challenging anyone to purposely flip a Phantom 4 and explain how they did it.  No one could. There was no bird strike, no broken props, no weather issue, wind at 2.5 mph out of the southwest at ground level and temperature of 54 degrees F.  All this data was presented to DJI including a video made with my cell phone seconds after the crash that clearly showed a dent in the gray area exactly matching the lens ring on the camers, proving that it had to have crashed upside down for this to happen.  -----  I could continue but I am just getting upset all over again at DJI's lies and disrepect of their customers by going to such great lengths to avoid refunding $239.00, and admitting that something indeed happened to the drone that was not pilot error.  All this was posted here in February, 2017 if anyone would care to read up on the crash.  I warn you though, it was a very lenghty posting with many comments with DJI-Ken, who never produced what he promised!  He finally stopped replying to me and after some time, I finally got DJI-Natalie to get the prop retainer springs sent to me after 7 weeks.  There are very many obvious questions that DJI never answered that are all listed in my February postings.  So, yes, Phantoms do flip and crash and DJI never admits it.
Thanks
Jim
WA5TEF