Update on my Crash

[sar104]

I'm just criticizing the quality not destroying your craft in art. Everybody has their own style. Just like you guys criticized how I need to learn how to fly and need to learn my aircraft. been flying for over 2 and a half year now with the Phantom 3 Pro. I bought the Phantom 4 Pro to take advantage of the Tripod Mode and the Obstacle performance, as well as the stronger motors. So far, my P3P has way more control and reliability as I never had a situation like I experienced with my P4P. Then again people are telling me not to fly in between buildings and to learn my aircraft limitation when posting a video of you flying through a cave or mountain like environment with a much tighter space proved no point at all other than my aircraft had a malfunction and yours didn't lol. Had nothing to do with my flying. The GPS dropped and sent the aircraft into immediate death spiral. Had your aircraft lost GPS while you were flying through those caves / streams. It would have spun out, hit the rocks and crashed into the water with same results lol.

You have provided no evidence in either of the threads that you started that there was any malfunction of your aircraft. Loss of GPS does not, and did not, lead to a "death spiral", immediate or otherwise. @OOO also stated perfectly clearly that his aircraft was in ATTI mode - not surprising since there is no chance of a GPS lock in that kind of location. It's perfectly controllable if you know how to fly it, as demonstrated in the video above. You quite likely had a more challenging situation due to stronger winds, but that's not the aircraft's fault.

 

[sar104]

So I do not understand why you would not use the GPS , and than if it went into atti mode you deal with it . ???

Almost no chance of enough satellites in that location, or even any at all down by the water. Better to put it into ATTI to start with to avoid surprises.

 

[OOO]

So I do not understand why you would not use the GPS , and than if it went into atti mode you deal with it . ???

In this cave-like place I had no GPS signal (zero satellite). Thus no way to fly in regular mode. In my crash video I was flying in regular mode but the aircraft went into ATTI mode upon loss of GPS signal. At that times, I was very new to drone flying and had almost no knowledge on flying modes. Disoriented, confused and finally crashed. After this crash, while waiting for repair, I had enough time to read and re-read all manuals. Most importantly, I found this forum and your posts helped me a lot. After crash, I remember trying to blame DJI and the aircraft. Then I realized that the problem was my ignorance and incompetence, not DJI or the aircraft.

 

[sar104]

Its obvious that you fly your drone like a Kite, everything has to be perfect, and that is great, but I fly in my house and its covered in concrete slabs and 4 stories down and all i need for a 26 minute flight is just 1 satellite. So if this really true than I should not be able to fly in such horrific conditions and yet I can.

I also fly my drone down the river while I am inside the house and again, that should not be possible.

Some things do not add up. That is the problem I have, If only the Phantom were to crash in my house, in my building than I would understand it, but for some reason my Phantom 4 Pro has superpowers and that bothers me.

I do hear what your saying about perfect flying conditions , but I want to fly my drone , not dream about flying it.

You may have misunderstood the flight mode that you are using. Firstly, with just one satellite it is physically impossible to determine position. Theoretically a 2-D fix on a defined geoid is possible with 2 satellites, and a 3-D fix with 3. In practice, even a 2-D fix requires 3 satellites and a 3-D fix requires 4. For acceptable accuracy for flight purposes the DJI FC will not even attempt P-GPS with less than 7 locked. In terms of flying indoors, it is possible to get an approximate position with sufficient satellite signals but the derived motion will be incorrect because the signal paths will not be direct.

Anyway - indoors as you described, if you are seeing positional control, the aircraft would have to be using vision positioning - there is no other alternative.

 

[PhantomWetSuits]

You may have misunderstood the flight mode that you are using. Firstly, with just one satellite it is physically impossible to determine position. Theoretically a 2-D fix on a defined geoid is possible with 2 satellites, and a 3-D fix with 3. In practice, even a 2-D fix requires 3 satellites and a 3-D fix requires 4. For acceptable accuracy for flight purposes the DJI FC will not even attempt P-GPS with less than 7 locked. In terms of flying indoors, it is possible to get an approximate position with sufficient satellite signals but the derived motion will be incorrect because the signal paths will not be direct.

Anyway - indoors as you described, if you are seeing positional control, the aircraft would have to be using vision positioning - there is no other alternative.

This was alarming , but excellent post with some great information, was this in the manual, I missed that part if it was. Thank you

 

[PhantomWetSuits]

In this cave-like place I had no GPS signal (zero satellite). Thus no way to fly in regular mode. In my crash video I was flying in regular mode but when I lost GPS signal the aircraft went into ATTI mode. I was very new to drone flying at that time and had no knowledge on flying modes. Disoriented, confused and finally crushed . After this crush, while waiting for repair, I had enough time to read and re-read al manuals. Most importantly, I found this forum and your posts helped me a lot. After crash, I remember that I was trying to blame DJI and the aircraft. But then I understand that it was totally my fault.

That is good to know, Atti mode can be a surprise so I understand the logic. I have to admit the satellites are a bit of a mystery to me as i called DJI and they mentioned that many of the Satellites are ground based, but could not tell which ones or where. Very interesting.

 

[sar104]

This was alarming , but excellent post with some great information, was this in the manual, I missed that part if it was. Thank you

I can't remember how much detail on this is in the manual. For those of us who have been flying these things since the P1/P2 days it's just common knowledge. Additionally, if you spend any time analyzing flight logs you get to see it in action. At least with the Phantom range you can select ATTI mode to practice. The Mavic owners have no such option, at least without a little software modification.

 

[sar104]

That is good to know, Atti mode can be a surprise so I understand the logic. I have to admit the satellites are a bit of a mystery to me as i called DJI and they mentioned that many of the Satellites are ground based, but could not tell which ones or where. Very interesting.

Ground-based satellites? Oxymoron of the day...

 

[PhantomWetSuits]

I can't remember how much detail on this is in the manual. For those of us who have been flying these things since the P1/P2 days it's just common knowledge. Additionally, if you spend any time analyzing flight logs you get to see it in action. At least with the Phantom range you can select ATTI mode to practice. The Mavic owners have no such option, at least without a little software modification.

So what confused me on the post was the 7 satellites and yet I know I fly on 1 - 2 -3 in the house so that part is not making sense to me. Can yo clarify that for me. ?

 

[andy_k]

if you only have 3 satellites you will be flying in atti mode - that's not enough of a fix to give gps tracking

there is no such thing as a ground gps satellite - they are in a low level orbit

Global Positioning System - Wikipedia

flying indoors (or underground) uses the front, rear and downward sensors to avoid collisions

 

[PhantomWetSuits]

if you only have 3 satellites you will be flying in atti mode - that's not enough of a fix to give gps tracking

there is no such thing as a ground gps satellite - they are in a low level orbit

Global Positioning System - Wikipedia

flying indoors (or underground) uses the front, rear and downward sensors to avoid collisions

Ok my head just spun around like the exorcist. 3 Satellites im still in atti mode , so even if it says GPS I am in, Atti mode , will check that out with my next flight in the house. Thank you

 

[Meta4]

This thread is showing a big lack of understanding of GPS and atti mode.
I'll try to clarify some of it.

please keep in mind, in such places ATTI mode is your best friend

When you have no GPS satellites, atti mode isn't a friend, it's your only option.
Your Phantom is in atti mode whenever it has insufficient GPS satellites for a GPS position fix regardless of the position of your flight mode switch.
Less than enough sats = Atti mode.

Had your aircraft lost GPS while you were flying through those caves / streams. It would have spun out, hit the rocks and crashed into the water with same results lol.

LOL indeed ... you may have flown for a while but you haven't learned anything about GPS.
In a cave there is no way to receive GPS satellite signals.
His Phantom didn't lose GPS .. it never had GPS but mysteriously it never spun out, hit the rocks and crashed into the water.
Perhaps it had something to do with the pilot knowing what he was doing with the controls and there being no wind in a cave?

I fly in my house and its covered in concrete slabs and 4 stories down and all i need for a 26 minute flight is just 1 satellite.

Your Phantom flies in the house with one sat because it is in atti mode.
Being in atti mode doesn't mean you automatically crash.
It just means you don't have the benefit of GPS position holding.

I also fly my drone down the river while I am inside the house and again, that should not be possible.

You are in your house and the Phantom is outdoors where it can receive GPS sat signals as you'd see on your screen.
Your controller indoors doesn't need GPS.

i called DJI and they mentioned that many of the Satellites are ground based, but could not tell which ones or where.

Ground-based satellites ??? What does that even mean?
If you'd asked them they would have also told you that DJI sell striped paint and left-handed screwdrivers or that submarines have screen doors and helicopters have ejection seats.

So what confused me on the post was the 7 satellites and yet I know I fly on 1 - 2 -3 in the house so that part is not making sense to me. Can yo clarify that for me. ?

With your handheld GPS you need to receive signal from 4 sats to get a proper 3D fix.
It was easy to understand GPS sat numbers with the earlier models like the Standard because they only received one kind of satellite (the US GPS system).
Because it's possible to get a poor fix with on;y 4 sats, DJI programmed the Phantom to only consider a fix good when it came from 6 or more sats.
That's no problem up in the sky where your Phantom will usually find more than 6 sats anyway.
With Phantoms after the Standard it gets confusing because they receive US GPS sats and Russian Glonass sats.
However they need at least 6 sats of one type before a fix is considered valid.
You could have 5 GPS sats and 4 Glonass sats for a total of 9 sats but still be in atti mode until you find a 6th GPS sat.
This isn't often a problem unless you fly from a location where your Phantom only sees a part of the sky.

3 Satellites im still in atti mode , so even if it says GPS I am in, Atti mode

You won't get the green GPS acknowledgement until you get enough sats for a GPS fix.

 

[OOO]

This thread is showing a big lack of understanding of GPS and atti mode.
I'll try to clarify some of it.

When you have no GPS satellites, atti mode isn't a friend, it's your only option.
Your Phantom is in atti mode whenever it has insufficient GPS satellites for a GPS position fix regardless of the position of your flight mode switch.
Less than enough sats = Atti mode.

LOL indeed ... you may have flown for a while but you haven't learned anything about GPS.
In a cave there is no way to receive GPS satellite signals.
His Phantom didn't lose GPS .. it never had GPS but mysteriously it never spun out, hit the rocks and crashed into the water.
Perhaps it had something to do with the pilot knowing what he was doing with the controls and there being no wind in a cave?

Your Phantom flies in the house with one sat because it is in atti mode.
Being in atti mode doesn't mean you automatically crash.
It just means you don't have the benefit of GPS position holding.

You are in your house and the Phantom is outdoors where it can receive GPS sat signals as you'd see on your screen.
Your controller indoors doesn't need GPS.

Ground-based satellites ??? What does that even mean?
If you'd asked them they would have also told you that DJI sell striped paint and left-handed screwdrivers or that submarines have screen doors and helicopters have ejection seats.

With your handheld GPS you need to receive signal from 4 sats to get a proper 3D fix.
It was easy to understand GPS sat numbers with the earlier models like the Standard because they only received one kind of satellite (the US GPS system).
Because it's possible to get a poor fix with on;y 4 sats, DJI programmed the Phantom to only consider a fix good when it came from 6 or more sats.
That's no problem up in the sky where your Phantom will usually find more than 6 sats anyway.
With Phantoms after the Standard it gets confusing because they receive US GPS sats and Russian Glonass sats.
However they need at least 6 sats of one type before a fix is considered valid.
You could have 5 GPS sats and 4 Glonass sats for a total of 9 sats but still be in atti mode until you find a 6th GPS sat.
This isn't often a problem unless you fly from a location where your Phantom only sees a part of the sky.

You won't get the green GPS acknowledgement until you get enough sats for a GPS fix.

Meta4, thanks for the great info and clarification, as usual. Yes if I don’t have GPS signal then ATTI mode is my only option. That what I was trying to say but sometimes my English limits me. In addition, sometimes I intentionally put my aircraft into A-mode even if I have enough GPS signal at the beginning of the flight.

 

[PhantomWetSuits]

This thread is showing a big lack of understanding of GPS and atti mode.
I'll try to clarify some of it.

When you have no GPS satellites, atti mode isn't a friend, it's your only option.
Your Phantom is in atti mode whenever it has insufficient GPS satellites for a GPS position fix regardless of the position of your flight mode switch.
Less than enough sats = Atti mode.

LOL indeed ... you may have flown for a while but you haven't learned anything about GPS.
In a cave there is no way to receive GPS satellite signals.
His Phantom didn't lose GPS .. it never had GPS but mysteriously it never spun out, hit the rocks and crashed into the water.
Perhaps it had something to do with the pilot knowing what he was doing with the controls and there being no wind in a cave?

Your Phantom flies in the house with one sat because it is in atti mode.
Being in atti mode doesn't mean you automatically crash.
It just means you don't have the benefit of GPS position holding.

You are in your house and the Phantom is outdoors where it can receive GPS sat signals as you'd see on your screen.
Your controller indoors doesn't need GPS.

Ground-based satellites ??? What does that even mean?
If you'd asked them they would have also told you that DJI sell striped paint and left-handed screwdrivers or that submarines have screen doors and helicopters have ejection seats.

With your handheld GPS you need to receive signal from 4 sats to get a proper 3D fix.
It was easy to understand GPS sat numbers with the earlier models like the Standard because they only received one kind of satellite (the US GPS system).
Because it's possible to get a poor fix with on;y 4 sats, DJI programmed the Phantom to only consider a fix good when it came from 6 or more sats.
That's no problem up in the sky where your Phantom will usually find more than 6 sats anyway.
With Phantoms after the Standard it gets confusing because they receive US GPS sats and Russian Glonass sats.
However they need at least 6 sats of one type before a fix is considered valid.
You could have 5 GPS sats and 4 Glonass sats for a total of 9 sats but still be in atti mode until you find a 6th GPS sat.
This isn't often a problem unless you fly from a location where your Phantom only sees a part of the sky.

You won't get the green GPS acknowledgement until you get enough sats for a GPS fix.

This was interesting and a good to know, best read so far.

 

[sar104]

So what confused me on the post was the 7 satellites and yet I know I fly on 1 - 2 -3 in the house so that part is not making sense to me. Can yo clarify that for me. ?

@Meta4 mostly answered your question. But I'm puzzled if you are saying that you have observed situations where the FC is reporting only 3 locked satellites but showing P-GPS mode. That's simply not possible, even theoretically, so I think that you must be misremembering. If not then that would have to be a bug in the firmware, and I'd be very interested to see the flight logs from such a flight.

 

[OOO]

Thanks sar104, I really appreciate your efforts. In ATTI mode, is there any other force that makes aircraft unstable except wind?

 

[sar104]

Thanks sar104, I really appreciate your efforts. In ATTI mode, is there any other force that makes aircraft unstable except wind?

Nothing significant. But bear in mind that a Phantom hovering in ATTI mode is, at best, in neutral equilibrium, and so it will tend to drift slowly and randomly from its starting point, even in the absence of any air currents.

 

[PhantomWetSuits]

Well just got the quote from DJI for my crash on November 13th
$266. What surprises me is I don't see the price for my Camera/Gimbal which was pretty much broken off and hanging by a wire. I'm going to use my DJI Refresh Protection Plan. But, I just hate the fact they used data to say I RC input was responsive and how I did a full pitch foward and a roll right and yaw left leading to a crash. It was in P-GPS mode. But, it was in "TRIPOD mode". Anybody that has flown in tripod mode knows the speed is limited. In the video you can see I'm reaching max speeds in tripod mode and then out of nowhere the aircraft speeds up and starts spinning in speeds way faster than tripod mode even allow. I'm very confused. But, I guess I just don't have a leg to stand on.

Heres the video link for those who did not see my original post
Dropbox - DJI_0012.MOV

Dont Panic this was older software from April of 2017. but the Tripod mode switch to Atti mode is still happening.
That is why I asked you Drew what software you were using.

I thought you would find this interesting. as others have pointed out Tripod mode warns you that you need a strong GPS signal.
Watch what happens when my strong Signal of 23 satellites drop out of existence and the Bird drops into Atti Mode Fly away.

Notice the crazy spin, look familiar Drew, Yep once that happend I got a lot of Flack from the Monkey crowd about how I screwed up and was not prepared, not ready, blah blah blah.

This was using firmware back from April of 2017 and the good news for me was that after Filing a claim with DJI they offered me a %100 coupon for a brand new Phantom 4 Pro not once, but Twice .

I was not flying between anything and the original video with some audio showed I was in an empty field .

I waited till the second update and sure enough I had the exact same thing happen and so I filed for number 2 until I got another coupon.

I was keeping in touch with DJI about this problem and I got the go ahead to fly again number 3 , this time no magnetic interference and no Yaw error and thought this issue might be fixed but it seems TRIPOD mode is using a lot of technology to get it that stable and that is why they have the warning flying in Tripod mode.

Take a look at the fly away and you will see it is perhaps not the best mode to fly in as I just now fly in P mode and go slow for the shots because each time it does switch to Atti mode , I have no control whats so ever.

Here is just some of the video that I showed DJI and notice the 23 satellites vaporizing and the dead spin from the Yaw Error .
I was using the Pro Plus controller so I also had audio for them to hear .

Now that I have a better understanding of how tricky Tripod mode is for the Phantom , I prefer to just stay away as many have gotten caught in that Spin to Atti mode with no control.

I do feel very confident in the newest firmware , as we have made all are test in the rain and the snow and so far it is solid, but the Tripod mode remains a bit of a mystery as to how strong the signal needs to be , because 23 satellites to me was a lot as we now fly near the lake at around 7 to 11 satellites.

 

[PhantomWetSuits]

@Meta4 mostly answered your question. But I'm puzzled if you are saying that you have observed situations where the FC is reporting only 3 locked satellites but showing P-GPS mode. That's simply not possible, even theoretically, so I think that you must be misremembering. If not then that would have to be a bug in the firmware, and I'd be very interested to see the flight logs from such a flight.

I am working on that Puzzle for you , talk soon, Thanks again for the posts.

 

[sar104]

Dont Panic this was older software from April of 2017. but the Tripod mode switch to Atti mode is still happening.
That is why I asked you Drew what software you were using.

I thought you would find this interesting. as others have pointed out Tripod mode warns you that you need a strong GPS signal.
Watch what happens when my strong Signal of 23 satellites drop out of existence and the Bird drops into Atti Mode Fly away.

Notice the crazy spin, look familiar Drew, Yep once that happend I got a lot of Flack from the Monkey crowd about how I screwed up and was not prepared, not ready, blah blah blah.

This was using firmware back from April of 2017 and the good news for me was that after Filing a claim with DJI they offered me a %100 coupon for a brand new Phantom 4 Pro not once, but Twice .

I was not flying between anything and the original video with some audio showed I was in an empty field .

I waited till the second update and sure enough I had the exact same thing happen and so I filed for number 2 until I got another coupon.

I was keeping in touch with DJI about this problem and I got the go ahead to fly again number 3 , this time no magnetic interference and no Yaw error and thought this issue might be fixed but it seems TRIPOD mode is using a lot of technology to get it that stable and that is why they have the warning flying in Tripod mode.

Take a look at the fly away and you will see it is perhaps not the best mode to fly in as I just now fly in P mode and go slow for the shots because each time it does switch to Atti mode , I have no control whats so ever.

Here is just some of the video that I showed DJI and notice the 23 satellites vaporizing and the dead spin from the Yaw Error .
I was using the Pro Plus controller so I also had audio for them to hear .

Now that I have a better understanding of how tricky Tripod mode is for the Phantom , I prefer to just stay away as many have gotten caught in that Spin to Atti mode with no control.

I do feel very confident in the newest firmware , as we have made all are test in the rain and the snow and so far it is solid, but the Tripod mode remains a bit of a mystery as to how strong the signal needs to be , because 23 satellites to me was a lot as we now fly near the lake at around 7 to 11 satellites.

View attachment 91965

What you described in that video is mostly expected behavior after an IMU exception in any GPS mode. What caused the compass error is not clear, but it will lead to ATTI mode, whether you start in P-GPS or Tripod mode. As for not responding to stick inputs, I've seen lots of people assert that and then found from the logs that the aircraft responded appropriately to the stick inputs that were given. Unless you want to post the log file for that flight it's not going to be possible to conclude much at all on that issue.