Sudden data loss → RTL → mid-landing disarm & crash

ArduCopter
, ,
1

Hi everyone,

We’re flying a hexacopter with:

  1. Cube Orange flight controller

  2. Herelink air unit (connected via TELEM1 for telemetry and SBUS to RCIN) + Herelink controller

  3. Latest ArduPilot Copter firmware installed via Mission Planner

We’ve done several flights successfully and in the last flight, we tested Stabilize, AltHold, and Loiter modes, landed safely, then took off again in Stabilize, flew for around 20 seconds and suddenly, Mission Planner showed “data loss for x seconds” (counting up), and the pilot lost all control. We noticed the vehicle initiated RTL and during the RTL landing, it suddenly disarmed mid-air and crashed to the ground.

So I have opened the logs of this fight and can notice a radio error 2, and then failsafe was triggered, and then RTL was initiated, and then before the disarming event midair, I can notice that the failsafe was resolved, so I am guessing that it was like the channel restart or like restarting at the low PWM value on all channels, and as we have a button on channel 7 for arm and disarm in the Herelink controller, it disarms midair because of that.

So can we pinpoint from the logs why the initial data loss/radio late frame happened?

All help will be appreciated.

Here is the flight log uploaded in Google Drive: flight log - Google Drive

2

From the herelink manual :
”Autopilot mode selection must not be programmed to sbus channels. Mode selection should be configured to Mavlink commands within Solex or QGC to ensure predictable behavior in the event of signal loss or system reboot.”

3

Yes, after some research we found this mentioned in the manual and we will take it into account, thanks for pointing it out.
But now we want to know why the data loss or radio error occurred in the first place.

4

Radio availability is not 100% ,it could be anything. Interference, faulty antenna connection, reboot of herelink….
The vehicle worked as expected, and the crash was caused by the wrong arm/disarm setup.

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