Hi everyone!, I had a P4, and since I updated the firmware to the last version .700, I am experiencing frecuent altitude rises and drops. I mean, I noticed that it happens mostly with head wind, but I experienced it without wind too, and in other flights with head wind and an earlier firm version, doesn't happened. This normally happens when I'm goin forward at full throttle, and when happens, I hover until it stops. The last time, it began to go up and down, and reached 8'8 m/s going down without touching altitude stick, and appeared the message "max motor speed reached" when it stopped and began to go up again. This is scary, dangerous and unacceptable. Is the first time that I see the Phantom 4 going down this fast. The IMU and compass were calibrated. Was a night flight.

This version .700 is way bad for me. I'm looking forward to downgrade both aircraft and controller to the former version, and see if this happens (if the gimbal doesn't shut down in mid flight, thing that happened when I try to downgrade last time). Anyone is experiencing the same as me?

I'm sorry for the troubles. Just to verify, have you tried to calibrate the RC? Any difference? If still not, please kindly refer the tutorial video and export the flight log when the issue appears, we'd like to look into the exact status, thank you in advance!

I haven't heard or experienced this if you may, can you send a video of the drone losing altitude and gaining altitude, also show how you're not touching the controller.

Hi Susan and Alex. First of all, thank you for your answers. I didn't calibrated the RC, maybe that was the problem, because I reinstalled the firmware of the remote controller and the aircraft, and just linked it. I will do a test with all calibrated and, anyway, I will upload a screen capture of the flight route of DJI GO 4 where the stick inputs and altitude are shown. I also include the flight data. I downloaded more than one file, but the issue appears in the DJI GO 4 flight route viewer at 3:28 AM.

Flight data: https://drive.google.com/file/d/ ... kj/view?usp=sharing
DJI GO 4 flight route video:

Adrinaik Posted at 2018-3-26 07:51
Hi Susan and Alex. First of all, thank you for your answers. I didn't calibrated the RC, maybe that was the problem, because I reinstalled the firmware of the remote controller and the aircraft, and just linked it. I will do a test with all calibrated and, anyway, I will upload a screen capture of the flight route of DJI GO 4 where the stick inputs and altitude are shown. I also include the flight data. I downloaded more than one file, but the issue appears in the DJI GO 4 flight route viewer at 3:28 AM.

Flight data: https://drive.google.com/file/d/17VJ0idohogrEI-jEQSOebCgfLHN1iwkj/view?usp=sharing

Thank you, I'll look into it and get back to you asap

Do you have a gimbal guard fitted to protect the camera ?

Hi Aardvark, no, I have nothing attached to the aircraft.

P.D: Always that this happens use to be in relatively high altitudes (50 meters and above). Normally, when I'm flying at about 25/30 meters or below, I don't remember that happens, maybe the drone can stabilize quicker due to VPS... I don't know.

Hi again!, I could test the Phantom yesterday. I calibrated RC, IMU, compass, gimbal and visual sensors. I flew it in daylight in P GPS mode, also a little in Sports mode, with the sun shinning and the problem stays.

I flew it over an irregular land (there are little elevations and valleys along the surface) with not much wind (was quite calm) and, again, punctually, the altitude went crazy. 85 percent of the time, the drone was flying well, but 15 percent was going up and down, little by little. Starts slow and, if I continue going forward, the problem becomes more violent, until I have to stop, let it hover and recover altitude. The "max motor speed reached" advertence appeared again, but the vertical speed doesn't reached that crazy speed of the other flight (8.8 m/s).

I have to say too, that, even I have an altitude limit of 120 meters, it surpases that limit by a lot. In the second battery of this test flight, it ended up flying at 177 meters while the limit stablished in the configuration was 120. Then, I stopped and let the aircraft slowly descending to 120/115 meters.

I plan to downgrade firmwares of RC and AC and test it again. I'll post the results here.