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PX4 behaviour when RC Loss or Low Battery

These were tested and verified with PX4 v1.15.1

RC Loss​

  • When the RC is lost, the UAV either lands or returns to home (RTH, then lands) based on the configured settings.
  • If the RC is regained, the pilot will immediately regain control, and RTH/landing is canceled.

Low Battery​

Three thresholds can be configured: Warning, Failsafe, and Emergency. By default:

  • Warning: Displays a warning message.
  • Failsafe: Initiates RTH (this can be configured).
  • Emergency: Triggers an immediate landing.
  • When the Failsafe action is triggered (usually RTH), the pilot can disable it by changing the flight mode on the RC—for example, switching from Position mode to Altitude mode and back to Position mode. This overrides the failsafe RTH, and the pilot regains control. The failsafe action will not trigger again.
  • The same applies to Emergency mode—it can be overridden by changing the flight mode. Once overridden, it will not be triggered again.

Kill Switch​

  • The kill switch will immediately shut off all motors and AUX PWM outputs.