Details of my crash.
My
P4P Obsidian is not a new drone that I acquired from a family member (acquired by him second hand and never flown by him). I had flown the last couple of days after passing the obligatory French UAS exam and other administrative procedures. So at most a few hours experience in total. It needed an electronic ID and I acquired the Airbot Data. As I had 2 3-d printed bars to connect small flashlights to the landing gear (came with the drone) I used these to put at the back side of the landing skids next to each other as a small platform for the Airbot. This appeared to be a good place giving a good sight for the gps-receiver in the Airbot and not blocking the gps in the AC itself. Almost 3 minutes in my flight a warning appeared
Downward sensor error. Aircraft unstable at low altitude. Fly with caution. which I might have missed on the screen of the GL300E as I tend to fly looking at the drone and not on the screen of the controller, but the message is in the Flight log. At the end of the flight I used most of the battery (still has over 14% in it) and pushed the RTH button. Bird reached the 50 meter home flight altitude, cruised to the H location and started to descent. I thought it went really fast and maybe 5 meters above ground moved the left stick upwards which should have stopped the descent (I think). Well, it did not and crashed very hard on the concrete. Both landings skids are totally broken off. No damage to the camera and gimbal, no other damage to the drone. After the 'landing' the battery was unlocked and a bit outside the battery compartment. I have studied the controller flight data. At the moment I can not access the AC flight data as I took of the camera housing which has the usb port in preparation for the ordered new landing gear. When replaying the controller flight data file I do see the above mentioned message and some more like reaching the maximum altitude, starting the home flight, the battery warnings etc. But the file ends at 33 meters of altitude and a downward speed of 3 m/s, so about 10 seconds before hitting the ground. If I understand correctly, the controller flight data is registered every 10 seconds and the AC flight data file should have a lot more detail and a lot more data points. This could explain why I miss the last 10 seconds of this flight.
Looking back at the current data, I think the 2 3D-printed bars+Airbot are in the way of the downward sensors that sit at the back of the drone. So I am also trying to find a better place for this electronic ID box.
I still do not understand why the drone did not react to my stick movement by stopping the descent. During replay I verified that the stick movement is indeed left stick up.
I have flown (many hours) a small RC heli mostly inside and on a flight simulator before starting with this drone.
