Is it safe to connect to MP while flying?

Unfortunate copter crash in Loiter Mode.

4th flight of a new aircraft. Many aircraft built to same spec. Aircraft took off in Loiter mode, no visible signs of vibration, or any problem. After about 30 seconds of flying it simply dropped from the air and didn’t seem to try and correct itself at all. Engines seemed to go to Idle and not shut down. Aircraft had power while on the ground. Airframe powered back up and seemed to function normally, no visible issues noted on motors, all props survived… One battery didn’t…

I figure I’d jump to my possible suspects and not start from scratch with details on settings or exact airframe type. maybe focus more on order of operations.

Pilot decided to launch in Loiter, all systems good. Normal climb out and turn. While climbing out we had noticed mission planner wasn’t connected to aircraft. I hit the connect icon and the Parameters started to load, however very slowly. Half way through loading parameters the drone shut off and hit the ground. Mission planner screen showed “Land” flight mode frozen on the screen.

It looks like the autopilot log goes from start to finish, even past impact and to time battery was disconnected… Let me know if any details are needed however I don’t think there is an air frame issue here and I that I have done the unthinkable, which is try to connect while in flight. I really hope it was my mistake and not the hardware or firmware.

FW 3.5.2 Stable


Looks like a problem (transient) with wiring or ESC on RCOUT.C4
Try to check wiring; do the motor test in MP and see if there will be interrupts in motor work.

Thanks Sergey,

I have some new info. I checked the wiring to all ESC’s both signal and power and it looks normal. I tested each motor individually and together and no problems noted, they all powered up and armed like normal. Engine mounts 1 and 3 were broken mechanically but not electrically. Motors 2 and 4 have no damage.

While running motors I stressed the wiring and connectors, no noted interrupt. I looked at RC 4 out and it seems to be reacting to the aircraft rolling over, with out the proper response from the airframe.

I did test where I ran the aircraft without props in AltHold mode and tried to connect to the aircraft with data link and mission planner. It took 4 times as long but it did connect and the aircraft continued to operate normally.

I will post the video of it crashing shortly.

I guess the short answer to this question is that it is safe to connect while in flight or operation. Or it can be done and may work just fine.

After going over the aircraft I did find that the two main battery connectors don’t seem to have the friction on connection they should, they feel loose, I think this may have been a contributing factor or the culprit as bad battery connectors can choke off the ESC’s. Also the out side temperature was on the cold side around 35 degrees F.


@Lawrence_Dennis, have another look to your log and noticed Current goes zero. So this is not a single motor failure but something like a total power loss, or ESC shutdown?
Same time your FC voltage is good and the main thing is that FC saw there is a unexpected descending began and it tried to stop that descend. BTW is your FC powered by its own battery?

Personally I never heard about problems here. I believe if there was a firmware issue then we shouldn’t see in the log that FC constantly tries to maintain copter’s altitude.
The good chance to see if the MP connection was the reason or not is to compare a motor cutoff time and the connection time. But I don’t know if the MP connection somehow logged.

Thanks Sergey,

I think you are correct, no the Pixhawk is not powered by a battery but it does have back up redundant power supplies/regulators. Since they have capacitors that is probably why they were able to keep the Pixhawk on during the power interruption. It came down to the two main battery connectors out of spec and the cold weather. Thank you for your insight!!