Runaway P4

[warendsee]

Had a very strange event yesterday. Was flying my P4 at approximately 60 feet altitude, and began a slow ascent. All of a sudden I noticed it was screaming upward (at a rate faster than I had ever seen), at which point I lowered the throttle down to arrest the climb. Then it began dropping like a stone, as though the motors were completely off. I had no control. As a last ditch try before it cratered the nearby road, I hit the RTH, and it responded immediately and came back to base. I was in 'P' mode the whole flight.

Any ideas what caused this?

 

[John Locke]

Did you happen to recently install a gimbal guard on the bottom, attached between both landing gear?

 

[warendsee]

Did you happen to recently install a gimbal guard on the bottom, attached between both landing gear?

NO

 

[Meta4]

Any ideas what caused this?

Looking at the flight data is the way to go with in-flight mysteries.
Go to https://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions to upload your flight record.
Come back and post a link to the report it provides

 

[alwhite00]

Did you happen to recently install a gimbal guard on the bottom, attached between both landing gear?

Why would that cause issues? I was thinking of buying one.

 

[John Locke]

Why would that cause issues? I was thinking of buying one.

Because it messes with the VPS sonar and makes the craft YOYO up and down with no stick input. P3P's didn't have this problem, but P4 has a stronger VPS sonar signal to work at higher elevations. I've heard that some versions of gimbal guard do not exhibit this anomaly, but some designs cause problems. I had one that causes this problem.

 

[DocDiggler]

Because it messes with the VPS sonar and makes the craft YOYO up and down with no stick input. P3P's didn't have this problem, but P4 has a stronger VPS sonar signal to work at higher elevations. I've heard that some versions of gimbal guard do not exhibit this anomaly, but some designs cause problems. I had one that causes this problem.

Yep you can see some YouTube clips related to that problem
It's actually very dangerous I experienced that myself

 

[Deleted member 62848]

Yep you can see some YouTube clips related to that problem
It's actually very dangerous I experienced that myself

Oooooohhhhh yet to experience that one

 

[DocDiggler]

Just go to YouTube search phantom 4 yo yo effect the guy on that lake demonstrated that very well

 

[warendsee]

I looked at the log info on HealthyDrones.com (now AirdataUAV.com), but saw no anomalies per se. On the flight in question, the battery did show a fairly high temperature of 141.7f, which is still within limits.

I decided then to analyze the flight through the DJIGo App. (Open the DJIGo App, click the little 'paper airplane' icon at the top left of the screen. It'll prompt you to connect and turn on your P4, then click the paper airplane icon again. Up pops a list of all your flights. Click on the flight you'd like to see.)

The ascent seemed rather normal, vertical speed peaking at 4.9 mph. I centered the stick to arrest the ascent. Then, without moving the stick, the P4 started descending, vertical speed peaking at 5.4 mph. Again, no stick movement on my part to lower the P4.

 

[warendsee]

I looked at the log info on HealthyDrones.com (now AirdataUAV.com), but saw no anomalies per se. On the flight in question, the battery did show a fairly high temperature of 141.7f, which is still within limits.

I decided then to analyze the flight through the DJIGo App. (Open the DJIGo App, click the little 'paper airplane' icon at the top left of the screen. It'll prompt you to connect and turn on your P4, then click the paper airplane icon again. Up pops a list of all your flights. Click on the flight you'd like to see.)

The ascent seemed rather normal, vertical speed peaking at 4.9 mph. I centered the stick to arrest the ascent. Then, without moving the stick, the P4 started descending, vertical speed peaking at 5.4 mph. Again, no stick movement on my part to lower the P4.

Went online chat with DJI Service. The flight prior had a rough landing. Apparently the IMU needs recalibration as a result, and could have been the cause for anomaly.

 

[warendsee]

Per DJI, I re-calibrated the IMUs, Compass, Gimbal, and updated firmware. Did a test flight and the first few tests of an ascent resulted in a similar response of the P4 descending rapidly. However, after flying more, and repeating the tests, the issue seemed to be resolved. Not sure what this means.

 

[Meta4]

I looked at the log info on HealthyDrones.com (now AirdataUAV.com), but saw no anomalies per se. On the flight in question, the battery did show a fairly high temperature of 141.7f, which is still within limits.

Healthydrones is almost useless for investigating incidents (I'd like $1 for every time I've typed that).
If you want to look at flight data, the instructions were back in post #4.