P4P Fell Out of Sky For No Reason - DAT file attached

[jdwarren]

Hi everyone,

I was flying my P4P and next thing you know the screen goes black.

I immediately initiated RTH and look around but can't see the drone.

I look on my flight records to see its last known location and found it smashed on the ground.

I didn't hit anything and the props / battery were still in tact.

The camera had snapped off the gimbal.

I downloaded the DAT file to see if anyone can figure out what happened.

Link to file: P4P DAT FILE - Google Drive

Thank you for any help you can provide!

 

[Meta4]

I downloaded the DAT file to see if anyone can figure out what happened.

If you can post the .txt file from the app, I can look at some of the obvious possibilities and maybe eliminate some.

 

[Fly Dawg]

I was flying my P4P and next thing you know the screen goes black.

Hmmm....Might I ask one question? What were you doing? The attitude values are all over the place. Quick start? Quick Stop? Continuously at high speed??? I haven't seen this in a while....

 

[jdwarren]

Hmmm....Might I ask one question? What were you doing? The attitude values are all over the place. Quick start? Quick Stop? Continuously at high speed??? I haven't seen this in a while....

View attachment 114692

I was taking pictures of a building at varying altitudes and angles so that is why I was constantly stopping and starting again.

 

[Meta4]

I was taking pictures of a building at varying altitudes and angles so that is why I was constantly stopping and starting again.

If you post the .txt file we'll be able to tell a lot more.

 

[Fly Dawg]

If you post the .txt file we'll be able to tell a lot more.

Not really....It's just easier to read for fairly specific data. The .dat alway's has more, when you can get it it....You should know that.

 

[sar104]

At the end of that flight the aircraft was dropping fast (~ 0.5 g) in response to minimum throttle, and pitched backwards. If the throttle were centered suddenly in that orientation it would have put a significant disconnection force on the battery.

Unfortunately the motor voltage record doesn't show the usual voltage collapse that we generally see with battery disconnects, so it's not a particularly convincing explanation. I don't see anything in the event stream that looks suggestive of a problem either.

 

[Fly Dawg]

As mentioned above there is really not a "smoking gun" here to make a definite conclusion, however as I mentioned and as was mentioned by @sar104 there were significant "erratic" control inputs very near the end of the flight. This is also apparent during the flight. Starting and stopping at high speeds, numerous times is not good for the airframe integrity. Specifically the battery latch, which has been noted many times as a "flaw" ( If you will ) in the P4. These maneuvers can possibly loosen the battery latch and cause a disconnect, which can only be "assumed" to be the case here. You will note the erratic maneuvers in the flight profile.

 

[Hawk1Pilot]

This story caught my attention since I had a very similar incident with my phantom 4 advanced last Sunday. Except that I was not able to locate/recover the drone. We have been able to view the flight map, by downloading it from the go4 app. The last location reported, about 21 minutes into the flight, and probably 5 to 10 minutes after I lost total communication with the drone, was at an altitude of 111 feet, About 420 feet from take off location , and proceeding straight down. But both a ground and aerial search produced no results. I was expecting it to return to home as soon as I lost communications but that did not occur.

In the post above there appears to be much more data in the .DAT file, but apparently that is stored on board the SD card, correct? If so is there any other additional information that might be available to assist in this recovery?

I was also doing a commercial building shoot at the time. The first batteries worth of flying went flawlessly. But we immediately began getting multiple warnings ( strong wireless interference, weak GPS signal, compass error, etc.) immediately after takeoff for the second flight. I tried to fly at home manually in ATTI mode, but the Drone was apparently not responding during the time that we could still maintain visuals. Then we lost our communications.

Any suggestions would be greatly appreciated. Otherwise, I think I am literally grounded for sometime. Sad, sad.

 

[BudWalker]

This story caught my attention since I had a very similar incident with my phantom 4 advanced last Sunday. Except that I was not able to locate/recover the drone. We have been able to view the flight map, by downloading it from the go4 app. The last location reported, about 21 minutes into the flight, and probably 5 to 10 minutes after I lost total communication with the drone, was at an altitude of 111 feet, About 420 feet from take off location , and proceeding straight down. But both a ground and aerial search produced no results. I was expecting it to return to home as soon as I lost communications but that did not occur.

In the post above there appears to be much more data in the .DAT file, but apparently that is stored on board the SD card, correct? If so is there any other additional information that might be available to assist in this recovery?

I was also doing a commercial building shoot at the time. The first batteries worth of flying went flawlessly. But we immediately began getting multiple warnings ( strong wireless interference, weak GPS signal, compass error, etc.) immediately after takeoff for the second flight. I tried to fly at home manually in ATTI mode, but the Drone was apparently not responding during the time that we could still maintain visuals. Then we lost our communications.

Any suggestions would be greatly appreciated. Otherwise, I think I am literally grounded for sometime. Sad, sad.

There is another .DAT on your mobile device. Look here to see how to retrieve it.
How to retrieve a V3.DAT from the tablet

 

[Fly Dawg]

The last location reported, about 21 minutes into the flight, and probably 5 to 10 minutes after I lost total communication with the drone, was at an altitude of 111 feet, About 420 feet from take off location , and proceeding straight down. But both a ground and aerial search produced no results. I was expecting it to return to home as soon as I lost communications but that did not occur.

As mentioned above by @BudWalker , there is another .dat on the mobile device and also a .txt log file. You can upload the .txt file to the link below for conversion and visual replication of the flight path. The device .dat has more information but it must be converted differently. For quick analysis, the .txt file should also help. However, of note, once you lose downlink from the aircraft, the data stream stops. It is possible that there is enough information using both the .dat and the .txt to calculate an approximate location if necessary.

Log Viewer

 

[Hawk1Pilot]

As mentioned above by @BudWalker , there is another .dat on the mobile device and also a .txt log file. You can upload the .txt file to the link below for conversion and visual replication of the flight path. The device .dat has more information but it must be converted differently. For quick analysis, the .txt file should also help. However, of note, once you lose downlink from the aircraft, the data stream stops. It is possible that there is enough information using both the .dat and the .txt to calculate an approximate location if necessary.

Log Viewer

Thanks so much, Fly Dawg. That is very useful, and new, information I will definitely pursue this approach and report back.

 

[Hawk1Pilot]

There is another .DAT on your mobile device. Look here to see how to retrieve it.
How to retrieve a V3.DAT from the tablet

And thank you as well, BudWalker! I missed your post in the first readthrough.

 

[Fly Dawg]

I will definitely pursue this approach and report back.

If you need assistance with the files and/or analysis, post a link back here to the uploaded .txt log and we can assist you with that. For the .dat file you would need to upload that to a sharable site such as dropbox, etc...and place a link back here to the file.

 

[Hawk1Pilot]

I opened the .txt file and discovered that it shows a different location than the visual map we pulled when we were logged into the dji site via go4 last week. Not sure what we were looking at, but it was just a flight "map" with recorded info along the way. Went to loo for it, but not there. May be on a building roof top in the area.

I'd like to know what the .dat file may show. Here is a link to one recorded that day:

2019-09-22_11-32-37_FLY382.DAT

drive.google.com

there are a couple others as well, but this seems to have the lateest time stamp.

I can also provide the .txt file here it transfers into the dialog box.

DJIFlightRecord_2019-09-22_[11-33-28].txt

 

[Hawk1Pilot]

DJIFlightRecord_2019-09-22_[11-33-28].txt

drive.google.com

here's a link to the .txt file on google drive.

 

[Meta4]

here's a link to the .txt file on google drive.

Here's what the flight data looks like:

DJI Flight Log Viewer | Phantom Help

Upload and view DJI Phantom, Mavic, and Spark flight logs online

www.phantomhelp.com

It shows Yaw Errors from early on and right through the flight.
That's probably due to launching from a magnetically compromised area.
Launching from reinforced concrete is one of the most common causes.
Or the launch spot was very close to some steel object.

As a result the drone would have been difficult to control.
It commenced autolanding soon after 4:46.8 when it was 1200 feet away and 250 feet up in the air.
Being in atti mode, it continued drifting on the breeze as it autolanded.
Last recorded location before losing signal put the Phantom 1742 ft from home and still 111 feet up while it drifted further NE at 0-3 mph.
A rough calculation would put the drone approx 50 feet further to the NE from the last recorded position.
It may have landed on the road or parking area, in which case it's gone or perhaps it's stuck in trees approx 50 feet NE of here:

 

[Hawk1Pilot]

Meta4, thanks very much for the prompt analysis of the .txt file. I was there this pm and looked all around, including those several trees to the NE, but couldn't spot anything. Planning a flyover Monday to see what we can spot. After a week, I'm not hopeful, but...

Appreciation to all who responded to this thread today;

PS Would the .DAT file hold any other secrets?

 

[BudWalker]

This story caught my attention since I had a very similar incident with my phantom 4 advanced last Sunday. Except that I was not able to locate/recover the drone. We have been able to view the flight map, by downloading it from the go4 app. The last location reported, about 21 minutes into the flight, and probably 5 to 10 minutes after I lost total communication with the drone, was at an altitude of 111 feet, About 420 feet from take off location , and proceeding straight down. But both a ground and aerial search produced no results. I was expecting it to return to home as soon as I lost communications but that did not occur.

In the post above there appears to be much more data in the .DAT file, but apparently that is stored on board the SD card, correct? If so is there any other additional information that might be available to assist in this recovery?

I was also doing a commercial building shoot at the time. The first batteries worth of flying went flawlessly. But we immediately began getting multiple warnings ( strong wireless interference, weak GPS signal, compass error, etc.) immediately after takeoff for the second flight. I tried to fly at home manually in ATTI mode, but the Drone was apparently not responding during the time that we could still maintain visuals. Then we lost our communications.

Any suggestions would be greatly appreciated. Otherwise, I think I am literally grounded for sometime. Sad, sad.

The .DAT and .txt you submitted were only 308 secs. If the flight really lasted 21 minutes then there should be subsequent log files. Is there a FLY383.DAT? And, another .txt after DJIFlightRecord_2019-09-22_[11-33-28].txt?

 

[BudWalker]

This appears to be not your usual launch from a concrete spot with embedded rebar. There certainly was some toilet bowling at launch.

But, it didn't start until the P4 reached about 4 meters (red trace). The Yaw/magYaw separation (blue trace) would then oscillate with peaks corresponding to the northern most parts of the toilet bowling.

I'm going to guess that it was the parking structure to the west of the launch point that caused the Yaw/magYaw separation.

Which direction was the P4 facing at launch. The data shows it facing south.