Please select Into the mobile phone version | Continue to access the computer ver.
Lost My Phantom 4, can someone tell me how this happened?
1519 22 2018-10-10
Uploading and Loding Picture ...(0/1)
o(^-^)o
Air40
lvl.1
Flight distance : 291391 ft
Offline

So I lost my Phantom 4 a couple days ago, having it for only 3 days and I can't find it after looking around the area it last had connection. The problems is that I was at 350ft in order to avoid buildings, yes, apartment buildings. Flying around interference and large buildings wasn't a good idea in the first place but I was flying high and assumed I would maintain connection as long I as I stayed close. In fact, I didn't go more than 1,000 ft away. When I lost connection I initiated RTH and the drone started descending instead of ascending probably because it was set to a lower hight, again, I was flying at 350 ft. Even with the set RTH, it should of came home, but it didn't. I really can't make much sense out of this. I was flying in sport mode but that doesn't explain why RTH failed. Here is the link to the flight log: http://www.phantomhelp.com/LogViewer/BAGA83OW6L907S8NSIXE/

Hope someone can make sense out of this.
2018-10-10
Use props
Geebax
Captain
Australia
Offline

It is hard to say where to begin, you received just about every warning message the system has. Did you not see any of these?  It would appear that you took off from the footpath outside the Seven Eleven, which would be potentially a problem, as your aircraft was continuously reporting compass, yaw and speed errors. All of these errors are usually caused by a confused compass that was initialised in a magnetically dirty place. One of the many warnings is advising you of this: 'Magnetic Filed Interference. Exit P-GPS Mode'.

There is also a message advising you that your RTH path cuts though a no-fly zone: 'Current RTH route will pass a no-fly zone. Pay attention to the aircraft's position to avoid RTH failure.' This is quite possibly why the aircraft did not return home. It may have lost signal from you, and could not return home because it would involve flying through an no-fly zone, so it landed where it was. I think the lesson for you is to pay closer attention to the messages on the screen. Also, keep your speaker volume up high so you can hear the voice prompts from the box bitch.
2018-10-10
Use props
Labroides
Core User of DJI
Flight distance : 26781877 ft
  • >>>
Australia
Offline

I'm afraid it's all bad news.

Flying around interference and large buildings wasn't a good idea in the first place.
That part was correct.
You picked a very, very bad spot to fly from, probably much worse than you imagine.


When I lost connection I initiated RTH and the drone started descending instead of ascending probably because it was set to a lower hight, again, I was flying at 350 ft.

Even with the set RTH, it should of came home, but it didn't. I really can't make much sense out of this. I was flying in sport mode but that doesn't explain why RTH failed.
The Phantom in RTH will only ascend to the height you have set (it  was 361 ft) and if already at that height, or above it comes directly  home.
But your Phantom never went into RTH during the whole flight.

There are a whole bunch of issues affecting your flight but the most serious one is easy to see.
The flight record is peppered with compass error, speed error and yaw error warnings.  

(The GPS position nomatch messages are a false alarm and mean nothing).
A yaw error is very serious and often involved in incidents involving the loss of a Phantom.
The most common cause is from launching from steel or reinforced concrete surfaces.
Once the Phantom has a compass error and/or yaw error, it cannot use GPS for position holding and is in atti mode.
In that situation RTH will not work and the Phantom can drift with the wind.
A yaw error can also cause the Phantom to appear to fly away and become erratic.

An additional problem shows at 12:39 when the following message appears:
Current RTH route will pass a no-fly zone. Pay attention to the aircraft's position to avoid RTH failure


Even if the Phantom was not plagued with yaw/compass errors, RTH would have not been able to find it's way home because the no-fly zone would be like a wall in the sky.
It's not possible to tell where your Phantom ended up.


2018-10-10
Use props
DJI Paladin
Administrator
Flight distance : 318 ft

Offline

Hi, I'm really sorry to hear that. I would recommend you to contact our support team to start up a case: (https://www.dji.com/support?site=brandsite&from=nav). We have the professional data analysis team who would do their best to find out the  reason of the incident and then the corresponding resolution would be provided. You can also provide your case number here in case you need further assistance. Thanks for your support.
2018-10-11
Use props
ALABAMA
First Officer
Flight distance : 10442687 ft
United States
Offline

Definitely a doomed flight from the beginning.  Always heed any warnings and if any doubt, bring it back home immediately. Sorry this happened to you, but consider it a learning experience.
2018-10-11
Use props
ATJ
Second Officer
Flight distance : 17736 ft
Offline

ALABAMA Posted at 2018-10-11 03:06
Definitely a doomed flight from the beginning.  Always heed any warnings and if any doubt, bring it back home immediately. Sorry this happened to you, but consider it a learning experience.

You might want to check this post...……..

Anyone know of anybody being fatally injured from a drone
2018-10-11
Use props
Air40
lvl.1
Flight distance : 291391 ft
Offline

Labroides Posted at 2018-10-10 19:40
I'm afraid it's all bad news.

Flying around interference and large buildings wasn't a good idea in the first place.

Thank you for your response! I knew that the area I was flying in was one of the most interference plagued areas in the city but I flew there before and didn't have issues as long as the drone was very close. I still made a mistake not realizing the errors. I never thought too much about the compass errors because I saw them every second and I was flying fine. I didn't really know what the speed or yaw errors were. Could you explain that better? I thought that the compass error comes from the steel or reinforced concrete surfaces, not any other errors.
2018-10-11
Use props
Air40
lvl.1
Flight distance : 291391 ft
Offline

Geebax Posted at 2018-10-10 19:09
It is hard to say where to begin, you received just about every warning message the system has. Did you not see any of these?  It would appear that you took off from the footpath outside the Seven Eleven, which would be potentially a problem, as your aircraft was continuously reporting compass, yaw and speed errors. All of these errors are usually caused by a confused compass that was initialised in a magnetically dirty place. One of the many warnings is advising you of this: 'Magnetic Filed Interference. Exit P-GPS Mode'.

There is also a message advising you that your RTH path cuts though a no-fly zone: 'Current RTH route will pass a no-fly zone. Pay attention to the aircraft's position to avoid RTH failure.' This is quite possibly why the aircraft did not return home. It may have lost signal from you, and could not return home because it would involve flying through an no-fly zone, so it landed where it was. I think the lesson for you is to pay closer attention to the messages on the screen. Also, keep your speaker volume up high so you can hear the voice prompts from the box bitch.

Are you saying that the sidewalk I took off from had magnetic interference and caused ALL of the errors?
2018-10-11
Use props
Geebax
Captain
Australia
Offline

Air40 Posted at 2018-10-11 13:46
Are you saying that the sidewalk I took off from had magnetic interference and caused ALL of the errors?

Most probably. There is a common misconception that flying around items that contain steel or iron will cause errors, but it is mostly untrue. The problem is launching from those surfaces. When you switch on the aircraft, if it is sitting on concrete containing rebar, the compass fires up thinking that the readings are OK, but once it gets in the air, it finds out the readings were bad, but it now has no way of dealing with it, hence all the compass and yaw errors.
2018-10-11
Use props
Air40
lvl.1
Flight distance : 291391 ft
Offline

Geebax Posted at 2018-10-11 15:06
Most probably. There is a common misconception that flying around items that contain steel or iron will cause errors, but it is mostly untrue. The problem is launching from those surfaces. When you switch on the aircraft, if it is sitting on concrete containing rebar, the compass fires up thinking that the readings are OK, but once it gets in the air, it finds out the readings were bad, but it now has no way of dealing with it, hence all the compass and yaw errors.

Okay, thanks for clarifying but what kind of surface should I take off from and how far from steel or iron?
2018-10-11
Use props
Labroides
Core User of DJI
Flight distance : 26781877 ft
  • >>>
Australia
Offline

Air40 Posted at 2018-10-11 15:34
Okay, thanks for clarifying but what kind of surface should I take off from and how far from steel or iron?

Never launch from steel or reinforced concrete surfaces.
There's no simple distance.
A 1 inch bolt an inch from your compass could cause a problem but be fine at >6 inches.
You would probably need >6 feet distance from a car.
It's a combination of size and distance.
2018-10-11
Use props
Air40
lvl.1
Flight distance : 291391 ft
Offline

Labroides Posted at 2018-10-11 15:56
Never launch from steel or reinforced concrete surfaces.
There's no simple distance.
A 1 inch bolt an inch from your compass could cause a problem but be fine at >6 inches.

How do I know if it's reinforced concrete? Also, does it matter at what angle the drone is, like if it's on an angled surface?
2018-10-11
Use props
Labroides
Core User of DJI
Flight distance : 26781877 ft
  • >>>
Australia
Offline

Air40 Posted at 2018-10-11 16:56
How do I know if it's reinforced concrete? Also, does it matter at what angle the drone is, like if it's on an angled surface?

Most concrete is reinforced concrete.
Yes, try for a level surface as much as is possible.
2018-10-11
Use props
Roadstar1700
lvl.2
Flight distance : 1203484 ft
United States
Offline

Geebax Posted at 2018-10-11 15:06
Most probably. There is a common misconception that flying around items that contain steel or iron will cause errors, but it is mostly untrue. The problem is launching from those surfaces. When you switch on the aircraft, if it is sitting on concrete containing rebar, the compass fires up thinking that the readings are OK, but once it gets in the air, it finds out the readings were bad, but it now has no way of dealing with it, hence all the compass and yaw errors.

If the AC had a good compass cal to begin, the re-bar/metal in the concrete/ground will not change that calibration. You will get a compass error telling you not to fly as it thinks there's interference in the area.

If you take off with a normal compass reading and start flying around metal objects the compass will give false data to which way it's pointing and cause the AC to start rotating around trying to lock in on true north. It then switches to ATTI mode and shuts off the GPS system all the while keeping the compass online which does not make sense or help the situation out at all.

I had an instance where the compass had a previously good cal. I took off with a normal compass reading, but as soon as I approached a hillside it started to rotate out of control. I was able to get it down      
with little damage. Turns out that hillside was full of iron ore. I live in a region where there is a lot of ore mining that goes on. I verified that was the case using a compass app on my tablet. North was anywhere but North in that area.
2018-10-22
Use props
Geebax
Captain
Australia
Offline

Roadstar1700 Posted at 2018-10-22 15:55
If the AC had a good compass cal to begin, the re-bar/metal in the concrete/ground will not change that calibration. You will get a compass error telling you not to fly as it thinks there's interference in the area.

If you take off with a normal compass reading and start flying around metal objects the compass will give false data to which way it's pointing and cause the AC to start rotating around trying to lock in on true north. It then switches to ATTI mode and shuts off the GPS system all the while keeping the compass online which does not make sense or help the situation out at all.

'If the AC had a good compass cal to begin, the re-bar/metal in the concrete/ground will not change that calibration.'

That is not what the compass calibration is designed to do. Firstly, the compass is located in the bottom of the landing leg, so it is very close to any rebar in the concrete. Secondly, compass calibration is designed to tell the on-board system what parts of the magnetic pattern surrounding the aircraft belong to the aircraft itself, it has nothing to do with calibrating the compass for navigational puposes.
And yes, it launching from concrete containing rebar will most certainly influence the operation of the compass.

2018-10-22
Use props
Roadstar1700
lvl.2
Flight distance : 1203484 ft
United States
Offline

Geebax Posted at 2018-10-22 16:04
'If the AC had a good compass cal to begin, the re-bar/metal in the concrete/ground will not change that calibration.'

That is not what the compass calibration is designed to do. Firstly, the compass is located in the bottom of the landing leg, so it is very close to any rebar in the concrete. Secondly, compass calibration is designed to tell the on-board system what parts of the magnetic pattern surrounding the aircraft belong to the aircraft itself, it has nothing to do with calibrating the compass for navigational puposes.

Firstly, the compass is located in the bottom of the landing leg, so it is very close to any rebar in the concrete. Secondly, compass calibration is designed to tell the on-board system what parts of the magnetic pattern surrounding the aircraft belong to the aircraft itself

I agree with this.

it has nothing to do with calibrating the compass for navigational puposes

I don't agree here. You're saying if I fly my AC near a metal structure the compass won't be affected. It certainly will.

And yes, it launching from concrete containing rebar will most certainly influence the operation of the compass

If there is enough metal in the concrete you won't be able to launch the AC. It will tell you to re-cal the compass (bad idea) or move to a new location.
2018-10-22
Use props
Roadstar1700
lvl.2
Flight distance : 1203484 ft
United States
Offline

Air40 Posted at 2018-10-11 13:46
Are you saying that the sidewalk I took off from had magnetic interference and caused ALL of the errors?

Sorry to here about you loss of AC. I hope you find it.

There seems to be some misinformation about the compass. When you initially set the AC up for the first time you do a compass cal somewhere away from any metal sources (out in an open field, large back yard etc). Once the compass is calibrated it will be good for your future flights unless you travel quite a distance away from the first cal, then another cal should be performed.

If you try to take off with metal interference your app will tell you that there is interference in the area and relocate to another area before flying. If you get this error, do not re-cal the compass at the area of interference otherwise you'll tell the flight controller that the compass is now good to go (on the ground, near the metal), but as soon as you lift off and get away from the metal the compass will give you bad data and an uncontrollable AC.

Flying around metal buildings will affect the compass reading just as a handheld compass will not point north if you place it near metal.
2018-10-22
Use props
Geebax
Captain
Australia
Offline

Roadstar1700 Posted at 2018-10-22 19:51
Firstly, the compass is located in the bottom of the landing leg, so it is very close to any rebar in the concrete. Secondly, compass calibration is designed to tell the on-board system what parts of the magnetic pattern surrounding the aircraft belong to the aircraft itself

I agree with this.

No, I was not saying that if you fly near a metal structure the compass will not be affected. I was saying, quite clearly I thought, that compass calibration has nothing to do with calibrating the compass for navigational purposes.

The compass is initialised at power on, and if you do so while it is sitting close to a ferrous object, the aircraft will not always detect it, and can take off then experience confusing readings.

Flying near metal objects may or may not affect the compass. Firstly, it can only do so if it is a ferrous metal object, meaning iron or steel. Other metals will have no effect. And even so, it has to be a very large object to have any effect and you have to get really close it is before it affects the compass.

I was going to answer your point about calibrating the compass when you move a significant distance, this is not correct either, but I see Labroides has already addressed that point.





2018-10-22
Use props
Labroides
Core User of DJI
Flight distance : 26781877 ft
  • >>>
Australia
Offline

Roadstar1700 Posted at 2018-10-22 20:12
Sorry to here about you loss of AC. I hope you find it.

There seems to be some misinformation about the compass. When you initially set the AC up for the first time you do a compass cal somewhere away from any metal sources (out in an open field, large back yard etc). Once the compass is calibrated it will be good for your future flights unless you travel quite a distance away from the first cal, then another cal should be performed.
Once the compass is calibrated it will be good for your future flights unless you travel quite a distance away from the first cal, then another cal should be performed.
That's more misinformation, travel any distance you like and the Phantom won't require another calibration.
That's because calibrating has nothing to do with distance from anywhere.
Calibrating the compass does one thing only.
It lets the Phantom know which magnetic fields are part of the Phantom and it then assumes any other magnetic influences are the earth's magnetic field.
You should only ever calibrate the compass after modifying or rebuilding the Phantom.
2018-10-22
Use props
Roadstar1700
lvl.2
Flight distance : 1203484 ft
United States
Offline

Geebax Posted at 2018-10-22 20:26
No, I was not saying that if you fly near a metal structure the compass will not be affected. I was saying, quite clearly I thought, that compass calibration has nothing to do with calibrating the compass for navigational purposes.

The compass is initialised at power on, and if you do so while it is sitting close to a ferrous object, the aircraft will not always detect it, and can take off then experience confusing readings.

The compass is initialised at power on

If this is true then why is there a compass calibration procedure in the first place?

As far as the "traveling a long distance" and the need to perform another compass cal I remember reading this from another topic saying it can't hurt. Some members cal theirs before every flight. I only cal mine after firmware updates.

2018-10-23
Use props
Labroides
Core User of DJI
Flight distance : 26781877 ft
  • >>>
Australia
Offline

Roadstar1700 Posted at 2018-10-23 19:22
The compass is initialised at power on

If this is true then why is there a compass calibration procedure in the first place?

If this is true then why is there a compass calibration procedure in the first place?
See post #19 directly above your post for the answer to that question.

As far as the "traveling a long distance" and the need to perform another compass cal I remember reading this from another topic saying it can't hurt. Some members cal theirs before every flight. I only cal mine after firmware updates.

I remember reading all kinds of myths and misinformation, particularly regarding the compass.
Unnecessarily recalibrating your compass won't improve anything.
Phantom owners that actually understand what the compass calibration does, understand when it might be required.
And that's not when you've travelled any distance.
It's not when you've done a firmware update either.
The answer is something else that was given to you in post #19 above.
2018-10-23
Use props
Roadstar1700
lvl.2
Flight distance : 1203484 ft
United States
Offline

Labroides Posted at 2018-10-23 19:56
If this is true then why is there a compass calibration procedure in the first place?
See post #19 directly above your post for the answer to that question.

It makes sense what you say about getting a baseline calibration of the metal in the AC so it can ignore it for future flights and like I said I only cal my compass with firmware updates.

I was trying to get an answer from Geebax from what he means by the compass being initialised at power on. The compass already has good cal data stored in the flight controller from a previous compass cal procedure being performed. If there happens to be some metal in the area (re-bar or whatever) you might get a warning, but once you lift off and get away from the interference the compass readings go back to normal and you will have good controlled flight.

I've had 2 occasions where I almost lost my AC to water because of a compass error. One was my fault re-caling the compass in a metal surrounding and the other flying towards a hillside full of metal ore.
2018-10-24
Use props
Geebax
Captain
Australia
Offline

Roadstar1700 Posted at 2018-10-24 20:27
It makes sense what you say about getting a baseline calibration of the metal in the AC so it can ignore it for future flights and like I said I only cal my compass with firmware updates.

I was trying to get an answer from Geebax from what he means by the compass being initialised at power on. The compass already has good cal data stored in the flight controller from a previous compass cal procedure being performed. If there happens to be some metal in the area (re-bar or whatever) you might get a warning, but once you lift off and get away from the interference the compass readings go back to normal and you will have good controlled flight.

Calibration is one thing, initialisation is another altogether. When you switch on the aircraft, the nav system takes a reading of the compass to try and work out which direction it is pointing. If this is done on a surface containing ferrous metal, the compass will have no way of knowing that it is producing a false reading until the aircraft lifts off that area. Once it gets up a couple of feet, the compass will then be showing a different reading, and the nav system now realises this and pops up a compass error. Continuing to fly while it is flagging compass errors can lead to an uncontrollable aircraft. The only remedy is to land, switch off the aircraft, move away from the spot containing metal, then switch everything on again.

2018-10-24
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules