Serial port mirroring to Mission Planner over MAVLink (non-USB, in-flight)?

General
1

Hi all ,

I would like to ask about the official support and limitations regarding serial port mirroring over MAVLink.

My idea is the following:

While the vehicle is in flight, is it possible for Mission Planner (as GCS, connected via telemetry radio , not USB) to mirror or transparently forward one physical UART on the ArduPilot flight controller to the local PC, similar to how ’MAVSerial pass‘ maps GPS data to localhost:500?

More specifically:

  • The serial port is a normal UART on the flight controller (e.g. SERIAL5).
  • Mission Planner is connected via telemetry radio, not USB.
  • The goal is transparent, bidirectional serial data (terminal-style), not sending commands via MAVLink messages.
  • Similar in concept to ‘MAVSerial Pass’, but usable during flight and without a USB cable.

I found documentation and examples for:
Serial Passthrough (mostly UART ↔ UART or UART ↔ USB)
‘MAVSerial Pass‘ usage when Mission Planner is connected via USB

However, I could not find any confirmed examples or documentation that this works reliably over MAVLink telemetry links during flight.

So my questions are:

  1. Is this use case officially supported by ArduPilot?
  2. If not, is it fundamentally limited by MAVLink bandwidth / safety design?
  3. Is ‘MAVSerial Pass‘ intentionally limited to USB-connected GCS scenarios?
  4. Are there any recommended alternatives for accessing an onboard companion computer (e.g. Raspberry Pi) serial interface from GCS during flight?

Thanks in advance for any clarification.