Hexcopter crash in RTL mode

ArduCopter Copter 4.0
1

Hi
I fly with this build a lot of hours so far and never ran into something like that.

After flying in Loiter and AltHold modes, I experienced a GCS failsafe, and the drone changed to RTL as intended and started heading back home. While it was above its home location, the drone was descending normally, but within two seconds, it suddenly flipped upside down.

At this point, I had no control of the drone because the GCS failsafe, and the drone crashed into the ground.
Upon recovering the log from the drone, I found that between 18:14:367 - 18:16:514, the output to all the motors was not changing at all, even though the drone was flipping.

I viewed the release notes for all the later versions but did not find anything that I think could have caused the issue.
Any ideas on what could have caused this or how to prevent it from happening again?

Version: ArduCopter 4.0.4 on CubeBlack
Frame: hexa
log file: Logs/2023-03-07 10-18-05.bin at main · FleetWithMac/Logs · GitHub

2

Probably hardware failure of one of the ESCs or one of the motors.

3

I would say the IOMCU had a fault. Errors go up at the same time those motor outputs flatten.
You could update to latest stable firmware and do a few long hover tests at a safe altitude - assuming the poor old hex can be resurrected.
The updated firmware might catch whatever that fault was.

Or replace that Cube and only ever use it on the desk for tests.

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1 Like
4

@xfacta thanks a lot
Could it be that the telemetry is trying to connect again and again, causing the IO MCU to malfunction?