Lost Phantom 4...Please tell me how the P4 would respond
1350 30 2017-8-22
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fans8a3141ae
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Ok, so my brother decides to go drunk droning with my Phantom 4 at 3am.  His next bad decision was to attempt to fly the P4 thru the door opening at the motel he was staying at.  He clipped the door frame and the drone crash landed.  He picked it right up and activated the rotors and took off before the drone was even able to set its home point location.  He had the controller in the 'Attitude' flight mode.  The bad decisions continued to mount....he just pushed both sticks forward on the controller until it was approx 1000 feet away from him and approx 400 feet altitude.  He never hooked his phone to the controller.  The controller started to beep...the battery in the controller died moments later....He had no idea what to do besides sit and wait for it to return....it never did.  He only knew the general direction in which it flew off.  At nearly an hour later he calls me and I rush over there to look for it.  It has been over a month now since it left home.  Under the battery I have my name and number and a "reward if found" message to which I have received no calls.  I have little hope for its return at this point because I have spent many hours searching on foot...by 4 wheeler....and using my mavic pro to look from the air.  But if I understood a little more about how the P4 would react in this situation maybe I can narrow the search area a little bit.  So if the P4 was receiving a signal from the controller to go full speed ahead as well as climb in altitude, then suddenly lost signal from the controller, how is it programmed to react in that situation?  given the fact that it may not have a home point recorded...and the fact that it was dark....and its last signal from the controller had it in attitude flight mode.  I did a sync of the flight records with the controller.  There is no record at all of its last flight.

I have already learned my lesson from this...my brother is no longer allowed to play with my toys, especially while drinking.  LoL     Any help would be greatly appreciated.
2017-8-22
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Fractures
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I believe it would return to the last recorded home point, OR, hover in place and land at critical battery.
I am sorry for your loss but I must say.. I dont let anyone fly my drone much less take it out of my sight

edit: forgot the drone was in atti mode, it would have drifted until critical battery and then landed god knows where.
2017-8-22
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brandX006
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Fractures Posted at 2017-8-22 14:15
I believe it would return to the last recorded home point, OR, hover in place and land at critical battery.
I find this story quite amusing because I dont even let people fly my drone much less take it out of my sight

I don't any more.  I can laugh about it now since he has offered to pay for it.  But at 4am that night listening to all the bad choices he made back to back, I was not a happy camper to say the least.  LoL
2017-8-22
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Blériot53
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If the drone could respond, it would probably say:- " Go home and kick your brother's @$$ !!".
2017-8-22
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brandX006
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Blériot53 Posted at 2017-8-22 14:18
If the drone could respond, it would probably say:- " Go home and kick your brother's @$$ !!".

For real....and probably wouldn't wait an hour to let me know either  haha
2017-8-22
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ALABAMA
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If it had hit somebody, you would have already received a call
2017-8-22
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Nigel_
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I have never tried what happened!

But I would expect that it would record a home point as soon as it was happy it had a good GPS signal which would probably be within 100m of the launch point.  Even though it was in atti mode I would expect it to do a low battery return to home at some point and return to the home point.  So it should have come back to somewhere near the motel.

So my guess is that depending on how flat the terrain is, it either crashed into something, or it returned and landed on the motel roof directly above the room he tried to fly out the door of...
2017-8-22
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brandX006
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so since the controller was in ATTI mode when the controllers battery died, it would not have the benefit of GPS,  return to home or object avoidance (since it was dark anyway)?  At critical battery the drone would have just started descending? probably landed in the top of some pine trees that are in the direction it was last seen flying? (although his vision and ability to remember anything in a straight line were undoubtedly skewed, haha)
2017-8-22
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ALABAMA Posted at 2017-8-22 14:27
If it had hit somebody, you would have already received a call

Yeah, i'm glad it didn't hit anyone.  He flew right over a 4 lane street that is the busiest street in our city.  10,000 cars a day busy.  Granted at 3am it prob would have been close to deserted.  Also not far away is a Ford dealership with prob 100 brand new very expensive trucks scattered across several acres.  Yeah he and I both were very lucky that it managed to land someplace that it did no harm...but it sure is hidden well.
2017-8-22
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Nigel_ Posted at 2017-8-22 14:36
I have never tried what happened!

But I would expect that it would record a home point as soon as it was happy it had a good GPS signal which would probably be within 100m of the launch point.  Even though it was in atti mode I would expect it to do a low battery return to home at some point and return to the home point.  So it should have come back to somewhere near the motel.

Unfortunately I have searched high and low with a fine tooth comb for more than 200 yards in any direction from where he took off......This motel happens to be a seedy motel that has plenty of meth heads willing to search for days for $5   lol  no luck yet...they are still looking  lmao
2017-8-22
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Otto4
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i would say let him pay for a new one! he needs the lesson :-) a stupid and dangerous act for sure
2017-8-22
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DJI Susan
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I'm sorry to hear your loss. Generally, the Failsafe RTH will not work when the drone lost in passive ATTI mode and it would be difficult to find the drone. Maybe you can consider to buy a new aircraft without controller and charger.
2017-8-22
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Nigel_
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DJI Susan Posted at 2017-8-22 22:45
I'm sorry to hear your loss. Generally, the Failsafe RTH will not work when the drone lost in passive ATTI mode and it would be difficult to find the drone. Maybe you can consider to buy a new aircraft without controller and charger.

RTH will not work if it is in ATTI mode because there is no GPS or because of compass issues.

In this case the reason it was in ATTI mode was that the mode switch was set to ATTI so RTH should work as normal, it should have come home but we don't know where home was.
2017-8-23
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Labroides
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It's hard to get good info around here.
If launched without GPS and flown out into the open, it will get GPS fairly quickly and record a home point where it first gets GPS.

Three seconds after losing connection to the controller, it will initiate RTH and come back to the place where home was recorded as long as ....
RTH is set to a height that will clear any obstacles on the rth path, and
There is not a strong headwind situation that the drone can't fight against, and
The pilot hasn't already crashed it somewhere out there.
2017-8-23
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Labroides Posted at 2017-8-23 03:19
It's hard to get good info around here.
If launched without GPS and flown out into the open, it will get GPS fairly quickly and record a home point where it first gets GPS.

So while it is in the air, it will record its location as the homepoint as soon as the GPS gets a good signal?  Keep in mind it was in Attitude mode.  If RTH was then activated after it lost connection to the controller where would it return to?  the midair location it had recorded as the homepoint?  then just hover there or what?  My drone didn't do that, it never came back to anywhere close by at all.  
2017-8-24
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DJI Susan Posted at 2017-8-22 22:45
I'm sorry to hear your loss. Generally, the Failsafe RTH will not work when the drone lost in passive ATTI mode and it would be difficult to find the drone. Maybe you can consider to buy a new aircraft without controller and charger.

Thank you....I had already bought a new Mavic Pro and was actually selling the P4 to my brother when he had it fly off on him.  I did recently purchase a Trackimo tracking device that I have attached to my Mavic Pro just in case something like this happens to me.
Thank you.
2017-8-24
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Blériot53
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brandX006 Posted at 2017-8-24 13:25
Thank you....I had already bought a new Mavic Pro and was actually selling the P4 to my brother when he had it fly off on him.  I did recently purchase a Trackimo tracking device that I have attached to my Mavic Pro just in case something like this happens to me.
Thank you.

The moral of this story being :   Don't take your drone to some seedy downtown motel, get blind drunk and decide to do some night manoeuvres at 3am.
2017-8-24
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Labroides
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brandX006 Posted at 2017-8-24 13:20
So while it is in the air, it will record its location as the homepoint as soon as the GPS gets a good signal?  Keep in mind it was in Attitude mode.  If RTH was then activated after it lost connection to the controller where would it return to?  the midair location it had recorded as the homepoint?  then just hover there or what?  My drone didn't do that, it never came back to anywhere close by at all.

Yes ... it would return to the point where home was recorded (if the 3 points I mentioned did not apply).
It would not hover there but would descend until it could descend no more (because it landed).
2017-8-24
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Nigel_
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However it wouldn't necessarily land on the ground, quite likely it landed on a roof.
2017-8-24
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Nigel_ Posted at 2017-8-24 15:22
However it wouldn't necessarily land on the ground, quite likely it landed on a roof.

Had it been daylight instead of 3am would it used any of its downward object avoidance when it was trying to land?  I have checked all the open areas it could have landed such as roofs...fields...parking lots....roads....There are 2 wooded areas with pretty thick brush, i have checked the best I can from the ground as well as take video from my mavic pro from above then watching it back in slow motion from a big screen tv...since I do have some reflective tape on the missing P4 I am considering attaching a light to my mavic pro and doing some night recording and hopefully the tape could help reveal its location, especially if it is in the top of some of the big trees we have in south georgia.  I also have a IR illuminator that reflects off that tape really well...does anyone know if a Mavic Pro can see infrared light?
2017-8-24
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Blériot53 Posted at 2017-8-24 14:55
The moral of this story being :   Don't take your drone to some seedy downtown motel, get blind drunk and decide to do some night manoeuvres at 3am.

Exactly....drunk droning I call it   LoL
2017-8-24
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fansfb11ee43
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As the Home Point wasn't recorded, no device was fitted and was set on ALT when the signal was lost the P4 would have hovered and then when the battery drained to critical it would have landed by itself, goodness knows where.

Good luck
2017-8-24
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Labroides
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fansfb11ee43 Posted at 2017-8-24 22:45
As the Home Point wasn't recorded, no device was fitted and was set on ALT when the signal was lost the P4 would have hovered and then when the battery drained to critical it would have landed by itself, goodness knows where.

Good luck

Read post #14 to get the real story.
2017-8-24
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fansfb11ee43
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Labroides Posted at 2017-8-24 23:44
Read post #14 to get the real story.

My source looks like he's a bit unreliable, I'll have a chat and fill him in.
2017-8-25
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andy10
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I beleive you had taken into account the wind that night. In ATTI mode it could fly far from the supposed direction.
About these home point issues I think that no GPS means NO home point! And it was in no GPS mode (ATTI)!
I lost my once (pilot error) but I had flight path recorded so there was no big issue to find it. If there is hgh grass or something like that, it is difficult to see it even from 3m away.
2017-8-25
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andy10 Posted at 2017-8-25 01:40
I beleive you had taken into account the wind that night. In ATTI mode it could fly far from the supposed direction.
About these home point issues I think that no GPS means NO home point! And it was in no GPS mode (ATTI)!
I lost my once (pilot error) but I had flight path recorded so there was no big issue to find it. If there is hgh grass or something like that, it is difficult to see it even from 3m away.

"About these home point issues I think that no GPS means NO home point! And it was in no GPS mode (ATTI)!"

In ATTI mode it still uses GPS to calculate its position (displayed on map) and that of the home point, which is set as soon as sufficient satellites have been received. What it does not do is use GPS to hold the position of the aircraft when hovering, or keep it on course when windy.

The 'P' & 'S' modes are both  'Auto Hold' as written on switch.

Labroids is correct in post 14.
2017-8-25
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DJI Susan Posted at 2017-8-22 22:45
I'm sorry to hear your loss. Generally, the Failsafe RTH will not work when the drone lost in passive ATTI mode and it would be difficult to find the drone. Maybe you can consider to buy a new aircraft without controller and charger.

is it  true? becouse in tis demonstration (6:45min) RTH Works under ATTI mode after lost signal from RC (P4). Something changed??

Can you comfirm?

2017-8-25
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Nigel_
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RTH will always work if there is GPS reception, which there will almost always be if outdoors.
The position of the mode switch does not matter.

The most likely reason for it not coming home is someone cancelling the RTH since unfortunately the same button is used to both activate and cancel RTH, if it has already auto-activated then pressing the RTH button can cancel RTH.

If in doubt, turn off the controller, it will then set off home if it is not already on the way.
2017-8-25
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andy10
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Well, what is than the difference between P and ATTI ? In ATTI mode it is not holding the position. It's holding the high only and satellites have nothing to do with it.
2017-8-25
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Aardvark
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andy10 Posted at 2017-8-25 20:03
Well, what is than the difference between P and ATTI ? In ATTI mode it is not holding the position. It's holding the high only and satellites have nothing to do with it.

"It's holding the high only and satellites have nothing to do with it."

You are correct. But in ATTI mode it still uses the satellites to send its position back to your map and to know where it is relative to the Home Position. So in ATTI mode it can still return to home if needed, and the conditions are right for the RTH to work properly. If the wind is too strong then it will never come home, remember also that the aircraft slows down in RTH mode and does not come home at full speed.
2017-8-26
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andy10
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Thanks!  I did't know that. But isn't correct that if something go wrong at return home mode, it is still possible to bring it home in ATTI?
2017-8-30
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