Let me state my experience I had a couple o days ago. Went out with my 2 kids to our next to home park and start flying around VLOS just right after sunset. Had 3
batteries so by the time using the 3rd one, daylight was almost gone. What I noticed during the 3rd
battery's night flight are the following:
Spark was totally unstable when hovering. Even though it was responsive and accurate in joystick commands as usual, it was really struggling to hover in one place. It was moving slowly up and down (mostly downwards) and also left and right. The movement deviation was about 30cm to 50cm and if I let it hoover without any correction it will continue moving to where it wanted to go just as if it was in ATTI mode.
I immediately brought spark in front of me and start checking aircraft status parameters and found out I had 17 sats locked, GPS mode, and all other sensor status (compass, IMU) where ok. Furthermore, when I pressed RTH on purpose to see the aircraft's reaction, it tried to land about 10m away from where it took off. I played and experimented to the rest of the
battery and nothing changed.
My strong feeling is that night flight and especially when flying low, creates instability because the down sensor sees nothing at all confusing its systems.
Open to your thoughts.