Betaflight Failsafe

What Failsafe Does

Failsafe is the behavior Betaflight uses when the flight controller loses a valid radio control signal.

For normal FPV quads, configure the receiver to send no pulses / no data on signal loss. This lets Betaflight detect the lost link and run its own failsafe logic. If the receiver keeps sending fake channel values, Betaflight may think the link is still valid.

Failsafe Flow

flowchart TD
    A[Radio link is valid] --> B{Signal lost?}
    B -- No --> A
    B -- Yes --> C[Short signal validation]
    C --> D[Stage 1: channel fallback values]
    D --> E{Signal returns before guard time ends?}
    E -- Yes --> A
    E -- No --> F[Stage 2: selected failsafe procedure]
    F --> G[Disarm or landing behavior]

Stage 1

Stage 1 is the guard period after Betaflight detects bad or missing receiver data.

In this stage Betaflight applies the Channel Fallback Settings:

Auto: roll, pitch, and yaw go to center; throttle goes low.
Hold: keep the last valid channel value.
Set: use a fixed value that you choose.

By default, Stage 1 lasts for failsafe_delay, commonly shown as the guard time for Stage 2 activation. The common default is 1.5s, but check your firmware version and Configurator values.

If the signal returns during Stage 1, Betaflight exits failsafe and gives control back to the pilot.

Warning

The default Stage 1 throttle fallback is low throttle, so the quad can start falling before Stage 2 begins.

Stage 2

Stage 2 starts when the signal is still lost after the Stage 1 guard time and the quad is armed.

This is where the Stage 2 Failsafe Procedure is used. In the Failsafe tab you will usually see these procedures:

Procedure	Meaning	Typical result
`Drop`	Immediately stop motors and disarm	The quad falls straight down
`Land`	Try to descend using a configured throttle value	The quad keeps motors active for the landing delay, then disarms

Drop is the default and simplest option. It is often the safest choice for freestyle or racing because the quad stops flying instead of drifting away.

Land can be useful only when you understand the required throttle value. If the throttle is too high, the quad may climb. If it is too low, it may fall quickly. Wind, battery voltage, prop size, payload, and tune all affect the result.

At the end of the Stage 2 procedure, Betaflight disarms. After a failsafe disarm, you normally must move the arm switch back to disarmed before you can arm again.

Failsafe Switch

You can configure a transmitter switch in the Modes tab to trigger failsafe behavior manually.

Common switch behavior:

Stage 1: run Stage 1 first, then Stage 2 if the switch stays active longer than the guard time.
Stage 2: skip Stage 1 and activate the selected Stage 2 procedure immediately.
Kill: disarm immediately.

Use this carefully and test without props first.

Practical Setup Notes

Use flight-controller based failsafe, not receiver-only failsafe.
Receiver signal loss should produce no data to the flight controller.
For small FPV quads, start with Drop unless you have a clear reason to use Land.
Test with props removed: arm, raise throttle a little, turn off the transmitter, and confirm the motors stop after the expected delay.
Do not rely on Land until it has been tested in a safe open area.

Setting	Purpose
`failsafe_delay`	Stage 1 guard time before Stage 2 starts
`failsafe_procedure`	Selected Stage 2 procedure
`failsafe_off_delay`	Time before motors turn off in landing mode
`failsafe_switch_mode`	Behavior when failsafe is triggered from an AUX switch