Strange problem

[Psmith221]

I'm not exactly a stranger, I've had my Phantom 3 standard for quite a while, and tonight in my heavily wooded area my wife was burning leaves and it was very picturesque at dusk so I sent the Drone down on the roadway, warmed it up, calibrated it, launched it, took some pics, then moved it out into a more open area and sent it a loft. When I was done doing pictures at dusk I decided I would bring it back down amongst the trees onto the roadway. My depth perception in the dark is lousy. And no matter how much I tried to keep it away from the trees I clipped one. Then it did something very weird. There are a lot of trees in my yard. And it proceeded carom off five of them. Every time it would hit one it would get itself at an angle of about 70 degrees or more out of the horizontal, and proceed on to the next tree. Like I said it did this 5 times, and finally landed upside down at the base of an oak. It broke all of the props, 2 blade guards, and both legs. Unbelievably it did not break the camera or the gimbal. My concern is why did it continue this Behavior. I guess I should be thankful that it did, but I watched an absolute horror, as it continually got out of the horizontal comma to a vertical and then smashed into another tree, five times! it was a like a nightmare watching it bounce from tree to tree!
Has anybody else ever seen this Behavior? I know it's tough to come by but I'm really curious as to why it did this. Why didn't it crash right off the bat?

 

[Starz]

Never have heard of that one! But out of curiosity, why did you calibrate and was there a problem that made you think something needed to be calibrated. Compass or imu?

 

[Fly Dawg]

I know it's tough to come by but I'm really curious as to why it did this.

Give some data to work with to start. Upload you flight log to the link below and post a link to that back here. Im pretty sure you may see the results yourself first, but if not share the data back here and we can let you know. Instructions are on the link, if you have not done this before.

Log Upload

 

[WV. Rootman]

I was sweeping off to the left of a flag at sunset. I hit a high palm tree. It did a complete 360 while falling. When it up righted, it took off like a rocket 50 yrd. from me. It then stopped at crash elevation and hovered. Was I glad, because it took off out over the saltwater bay. I suppose if there were trees around, it would have ricocheted from one to another.

 

[3rdof5]

Its possible that the initial impact messed with the imu and then it just couldnt recover and then it pinballed its way down. But ss flydawg said, the flight log will tell all

 

[Rick218]

Possible to have damaged a prop causing unstable flight? Interested to see what the flight logs show!

 

[Thermographer]

I'm not exactly a stranger, I've had my Phantom 3 standard for quite a while, and tonight in my heavily wooded area my wife was burning leaves and it was very picturesque at dusk so I sent the Drone down on the roadway, warmed it up, calibrated it, launched it, took some pics, then moved it out into a more open area and sent it a loft. When I was done doing pictures at dusk I decided I would bring it back down amongst the trees onto the roadway. My depth perception in the dark is lousy. And no matter how much I tried to keep it away from the trees I clipped one. Then it did something very weird. There are a lot of trees in my yard. And it proceeded carom off five of them. Every time it would hit one it would get itself at an angle of about 70 degrees or more out of the horizontal, and proceed on to the next tree. Like I said it did this 5 times, and finally landed upside down at the base of an oak. It broke all of the props, 2 blade guards, and both legs. Unbelievably it did not break the camera or the gimbal. My concern is why did it continue this Behavior. I guess I should be thankful that it did, but I watched an absolute horror, as it continually got out of the horizontal comma to a vertical and then smashed into another tree, five times! it was a like a nightmare watching it bounce from tree to tree!
Has anybody else ever seen this Behavior? I know it's tough to come by but I'm really curious as to why it did this. Why didn't it crash right off the bat?

Don't take this the wrong way, but I probably would have paid money to watched that... just sayin...lol

 

[umanbean]

And no matter how much I tried to keep it away from the trees I clipped one. Then it did something very weird.

Possible to have damaged a prop causing unstable flight? Interested to see what the flight logs show!

Prop damage from first strike sounds most likely to me also.

If you'll upload your logs, Fly Dawg will analyze... then we'll know better what could have happened.

 

[Psmith221]

Thermographer, It was well worth the price of admission. As far as the logs are concerned, Evidently it suffered more damage than I thought. Now I can't get my PC to recognize the drone when plugged into the USB port after flight data was turned on in DJI GO.(the .dat files) I would love to get these off it. I don't know what that is all about.
I recalibrated the IMU, that night because it had never been launched from this location and it has been missing RTH by about 10 feet, of late, and I was trying to get its accuracy genned up.

At present the drone, brokenlegs and props, will fire up and warm up and reports no errors, and will come to "Ready to fly" status in a minute or two. Red lights up front Flashing green on rear.

But I Still cant get it recognized when connected to my PC.

Any more ideas?

 

[3rdof5]

Thermographer, It was well worth the price of admission. As far as the logs are concerned, Evidently it suffered more damage than I thought. Now I can't get my PC to recognize the drone when plugged into the USB port after flight data was turned on in DJI GO.(the .dat files) I would love to get these off it. I don't know what that is all about.
I recalibrated the IMU, that night because it had never been launched from this location and it has been missing RTH by about 10 feet, of late, and I was trying to get its accuracy genned up.

At present the drone, brokenlegs and props, will fire up and warm up and reports no errors, and will come to "Ready to fly" status in a minute or two. Red lights up front Flashing green on rear.

But I Still cant get it recognized when connected to my PC.

Any more ideas?

Sounds like all is well with the AC, make sure the USB cable is not a charge only cable and connect the AC to the PC after enabling flight data mode, not before. Also, in case ur not aware, connect to the USB port on the front of the AC itself, not the port on the camera gimble.

 

[Fly Dawg]

I would love to get these off it.

Try the link in Post#3 for the log from your phone or tablet. There may be enough information on that to see why the bouncing action occurred. That is always the first log to look at. The .dat files give more detailed information of coarse. But the device logs can certainly give a starting point.

 

[Psmith221]

Ok I had a bad USB cable, but fixed that issue.
I uploaded the flight log
DJI Flight Log Viewer - PhantomHelp.com
I also unpacked the .dat files from the drone using DatCon. Jeez, talk about getting run over with data. However, I tried looking thru it. Got overwhelmed but made some sence of it.

However the flight log does not offer much, after about 4 mins I sent it aloft
At about 7 minutes I told it to return to home.
At about 9 minutes and 26 secs I took control fearing it would not clear power lines and some of the tree tops. Was trying to guide it thru trees onto the roadway but it was now to dark for me to see all of the trees
At 10 min and 2.7 seconds it clipped its first tree limb. Then all hell broke loose.

If you look at the flight log, Over speed errors start and then it fell out of P-mode to ATTI, would recover, errors would go away, then hit the next tree, On and On and On.

If you look at the .dat files, you will see that its little brain was doing all kinds of wild things, changing mtr spds, up and down, braking all over the place. Altitude readings went haywire, imu and compass reading are all over the place.

I just don't know what to look for to determine if the first event actually broke a blade or what. It would be nice to determine whether it was a broken blade that started it all or perhaps lag time in the imu and computer to compensate or what?

The logs just go dead at 10m 10s. When I got to the drone final resting place, the battery was out, All of the blades were broken, and the legs. I assume the battery coming out killed the logs.

Yeah, Yeah I know this is a lot of overkill, especially since I replaced the blades and legs, and it is back to its normal self.

But I got beer to drink and am tired of reading numbers.

 

[Fly Dawg]

But I got beer to drink and am tired of reading numbers.

Understand that completely. Taking a wag, I would say a broken left front prop started the whole ordeal. When that happens, the aircraft could do most anything attempting to stabilize itself.

 

[Psmith221]

Thanks Flydawg. But just out of curiosity, why was your WAG the left front prop. and if you don't mind how do you get txttocsv to produce those graphs?

 

[Fly Dawg]

why was your WAG the left front prop.

Severe Pitch down, then Roll to the left and yaw CCW......You can download the CSV from the Phantom help site that you uploaded to. If you use the Verbose CSV file that is directly readable in Bud Walkers CSV View. Otherwise you can use Excel and/or an external graphing software for the CSV.

 

[Psmith221]

Thanks, I owe you a beer or two. Now that I look at it, it makes perfect sense. Ya learn somethin new ever dang day. Although I'm not going to try and duplicate that flight path again, I think I'll put the blade guards on it!

 

[Meta4]

However the flight log does not offer much,
At 10 min and 2.7 seconds it clipped its first tree limb. Then all hell broke loose.

The data shows the initial impact at 10:01.6 when the pitch, roll and yaw numbers change suddenly.
That tipped the Phantom over and it lost GPS (GPS health went from 5 to 1 almost immediately).
From then on, your Phantom did not have the benefit of GPS position holding.

I think I'll put the blade guards on it!

If you think you prop guards are required, a better idea would be to fly somewhere else.

 

[Psmith221]

It was a first and I live deep in a wooded area. the better idea was that I always took it elsewhere. But the pics of my wife burning leaves, and the sky colors got me feeling gutsy.

Maybe I should have had a beer instead.

I'll remember that next time.

 

[With The Birds]

Thanks Flydawg. But just out of curiosity, why was your WAG the left front prop. and if you don't mind how do you get txttocsv to produce those graphs?

You should be able to tell if you have a broken prop without any log analysis.

 

[Psmith221]

The point was not which or how many blades broke. They all Did. The point was to ascertain the reason for it's unusual and prolonged death spiral into 5 different trees.
After hitting the first tree, it managed to right itself and fly another40 feet.
Next tree, it flew on another 10 feet
Next tree, it flew on another 15 feet,
next tree, it flew on for 45 feet.