My brand new P4P went Ballistic to 1587 feet AGL I recently received a brand new P4P. I just sold a P4 to upgrade to this new P4P. First day, three flights everything seemed fairly normal. Second day started off good, and then I got my first shock on the third or fourth flight. For no apparent reason, the aircraft would not hover in place over bare pavement at 15 feet of altitude. It would drift away and not hold position. As it drifted it would not stay at altitude, it settled back to the ground. I constantly had to add forward left stick to gain back the altitude. I was in control mode “Mode 2”. I flew it out a few hundred feet and climbed to approximately 150 feet. It started drifting faster. I initiated a Return to Home and got a shocking surprise. The P4P immediately climbed straight up to approximately 530 feet (back left stick did nothing) when I was able to kill the return to home function and manually take control. I only had the RTH set at 40 meters (I pretty sure). It blew clear past the altitude limit I had set for RTH. I manually flew back to the home point and got my next shock… it would not descend at all! My batteries were getting low. I finally held the left stick all the way back and tried to fly forward for a couple seconds then backward for a couple seconds to slough off altitude. I did this repeatedly until I was able to get the aircraft back on the ground. This appeared to be the only way I could lose altitude. It would only descend at between 0.2mph and 0.7mph for the remainder of the flight. It took a long time to lose 530 feet and get it back on the ground. Also, top speed in any direction was only a maximu of 5.7mph. Thank goodness I didn't have any winds!!! When I landed my battery was a little over 10%. I completely recalibrated EVERYTHING. I even uninstalled DJI Go 4 and DJI Assistant 2 and re-updated both. I recalibrated the IMU, gimbal, compass, Remote controller, sensors, and reformatted the MicroSD card. I took it out the next day on day 3 and it flew great for the first 3 flights THEN I Got the shock of shocks. I took off to about 15-20 feet and it locked in altitude position I could not descend. I climbed slowly then gave it a burst of upstick to see if that did anything and that set off a ballistic nightmare. The P4P went straight up from 20 feet I think so fast I lost sight of it in seconds,. I pulled left stick all the way back, it did nothing! I could hear it screaming straight overhead. It went from about 20 feet to 1587 feet in 41 seconds. According to my calculations that's straight up at 27mph. I heard on the speaker that it had reached max altitude (apparently that stopped the ascent; I had the ceiling set at 500 meters I believe). I was shocked beyond measure. I could barely hear the aircraft (totally calm winds) but couldn't see the aircraft. I could see it on the DJI map. I pulled full left stick back (it was in "P" mode it backed up at 40mph. I immediately stopped it and pushed left stick forward it would only fly up to 5.7 mph for the rest of the flight in any direction. My next shock!!! It was stuck at altitude. It would not descend no matter what I did. I couldn't believe it. I got really nervous. I thought I would never see the aircraft again. I am a real life pilot and CFI and decided to try a technique to lose altitude. I started with a full battery and was now extremely concerned I would run out of battery before I could get the P4P back on the ground safely. I started flying forward to slough off altitude for a few seconds, then backward for a few seconds with the left stick in full back position the whole time. I did this constantly for 18 minutes and 41 seconds knowing if I quit I was going to lose the battle. It took almost 19 minutes to get it back on the ground. With this technique my average descent rate was only .94mph. When I finally landed I had 16% battery left. I basically used almost an entire battery just descending over the home point. I cannot put into words the gambit of emotions I went through in 25 minutes. I got it on the ground but will NOT fly it again (I have since sent it back to DJI, no word on prognosis yet). I spoke with DJI tech support, they said send it back for testing. After I completely recalibrated the P4P after the first occurrence, it seemed to fly ok for the first flight. I called DJI tech support to see if that might have resolved the issue, they said it probably did and I would probably be ok. This last flight was after that tech call. It didn't fix the problem AND it appears to be an intermittent problem (the worst kind?). The aircraft was not damaged thank goodness and I sent it in for analysis and ??? Has anyone else had this problem??? AND, if so what did you do about it or how did you correct the problem? Any ideas? Never had any problems like this with my P4.
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