# Flight Mode Configuration

This topic explains how to map flight modes and other functions to the switches on your radio control transmitter.


You must already have configured your radio in order to assign flight modes and functions.


PX4 allows you to select flight modes from a ground station (tablet or desktop) or from a radio control transmitter. If radio control and tablet are both connected, either system can change the mode and override the previous setting.

# What Flight Modes and Switches Should I Set?

Flight Modes provide different types of autopilot-assisted flight, and fully autonomous flight. You can set any (or none) of the flight modes described here. Most users should set the following functions, as these make the vehicle easier and safer to fly:

  • Position mode (multicopter, fixed-wing) - Easiest and safest mode for manual flight.
  • Return mode - Return to launch position by safe path and land (by default).
  • VTOL Transition Switch - Toggle between fixed-wing and multicopter flight configuration on VTOL vehicles.

It is also common to map switches to:

  • Mission - This mode runs a pre-programmed mission sent by the ground control station.
  • Kill Switch - Immediately stops all motor outputs (the vehicle will crash, which may in some circumstances be more desirable than allowing it to continue flying).

# Multi Channel vs Single Channel Mode Selection

PX4 (QGroundControl) supports two modes for mapping flight modes to transmitter switches/dials:

  • Single Channel Mode Selection: Assign up to 6 flight modes to switch positions encoded in a single channel.
  • Multi Channel Mode Selection: Assign modes to switch positions encoded in one or more channels. Some modes are hard coded to share channels, or are defined/set automatically based on other mode selections (the behaviour of multi-channel mode selection can sometimes be confusing).


The recommended approach is use Single Channel Mode Selection because it easy to understand and configure.

# Single-Channel Flight Mode Selection

The single-channel selection mode allows you to specify a "mode" channel and select up to 6 flight modes that will be activated based on the PWM value of the channel. You can also separately specify channels for mapping a kill switch, return to launch mode, and offboard mode.


In order to use this approach you will first need to configure your transmitter to encode the physical positions of your mode switch(es) into a single channel. We provide information on how this is done for the popular Taranis transmitter below (check your documentation if you use a different transmitter).

To configure single-channel flight mode selection:

  1. Start QGroundControl and connect the vehicle.

  2. Turn on your RC transmitter.

  3. Select QGroundControl icon > Vehicle Setup, and then Flight Modes in the sidebar.

    Flight modes single-channel


    If the screen opens in Multi Channel Mode click the Use Single Channel Mode Selection button to change screen.

  4. Specify Flight Mode Settings:

    • Select the Mode channel (above this shown as Channel 5, but this will depend on your transmitter configuration).
    • Move the transmitter switch (or switches) that you have set up for mode selection through the available positions. The mode slot matching your current switch position will be highlighted (above this is Flight Mode 4).


      While you can set flight modes in any of the 6 slots, only the channels that are mapped to switch positions will be highlighted/used.

    • Select the flight mode that you want triggered for each switch position.
  5. Specify Switch Settings:

    • Select the channels that you want to map to specific actions - e.g.: Return mode, Kill switch, offboard mode, etc. (if you have spare switches and channels on your transmitter).
  6. Test that the modes are mapped to the right transmitter switches:

    • Check the Channel Monitor to confirm that the expected channel is changed by each switch.
    • Select each mode switch on your transmitter in turn, and check that the desired flight mode is activated (the text turns yellow on QGroundControl for the active mode).

All values are automatically saved as they are changed.

# Taranis Setup: 3-way Switch Configuration for Single-Channel Mode

If you only need to support selecting between two or three modes then you can map the modes to the positions of a single 3-way switch. Below we show how to map the Taranis 3-way "SD" switch to channel 5.


This example shows how to set up the popular FrSky Taranis transmitter. Transmitter setup will be different on other transmitters.

Open the Taranis UI MIXER page and scroll down to CH5, as shown below:

Taranis - Map channel to switch

Press ENT(ER) to edit the CH5 configuration then change the Source to be the SD button.

Taranis - Configure channel

That's it! Channel 5 will now output 3 different PWM values for the three different SD switch positions.

The QGroundControl configuration is then as described in the previous section.

# Taranis Setup: Multi-Switch Configuration for Single-Channel Mode

Most transmitters do not have 6-way switches, so if you need to be able to support more modes than the number of switch positions available (up to 6) then you will have to represent them using multiple switches. Commonly this is done by encoding the positions of a 2- and a 3-position switch into a single channel, so that each switch position results in a different PWM value.

On the FrSky Taranis this process involves assigning a "logical switch" to each combination of positions of the two real switches. Each logical switch is then assigned to a different PWM value on the same channel.

The video below shows how this is done with the FrSky Taranis transmitter.

The QGroundControl configuration is then as described above.

# Multi-Channel Flight Mode Selection


We recommend you use Single Channel Flight Mode selection because the Multi Channel selection user interface can be confusing. If you do choose to use this method, then the best approach is to start assigning channels and take note of information displayed by QGroundControl following your selection.

The multi-channel selection user interface allows you to map one or more modes to one or more channels. There are some modes (and hence switches) that must always be defined, and the channel to which they must be allocated.

To configure flight modes using the multi-channel UI:

  1. Turn on your RC transmitter.

  2. Start QGroundControl and connect the vehicle.

  3. Select the Gear icon (Vehicle Setup) in the top toolbar and then Flight Modes in the sidebar.

    Flight modes multi-channel


    If the screen opens in Single Channel Mode click the Use Multi Channel Mode Selection button to change screen.

  4. Select the modes you want to assign to your switches and select the associated channel (selected modes will move in the user interface to be grouped by channel). There are a number of complications on the mode to channel assignments:

    • Some modes cannot be manually edited (are grayed out) because their channel and threshold level are automatically defined based on the values of other mode settings. For example:
      • Mission mode - is automatically assigned the same channel number as Hold (if the channel for Hold is defined by the user). If the channel for Hold is not defined, Mission mode is automatically assigned the same channel as Stabilized/Main mode. This, for example, prevents the user from defining Stabilized/Main and Mission mode on different channels, to ensure that the user cannot switch both modes ON at the same time.
      • Altitude mode - is automatically assigned the same channel number as Position Control (if it is defined), or otherwise the same channel as Stabilized/Main mode.
    • Assist mode - This mode is added to the same channel as Stabilized/Main mode if (and only if) Position Control is enabled and defined on a different channel than Stabilized/Main.
  5. Click the Generate Thresholds button.

    • This will automatically create threshold values for all modes, spread evenly across each channel for its assigned modes. For example, in the mode assignment shown above, most modes are assigned to mode 5, and you can see that the channel thresholds for each mode are spread evenly across the channel.

This mode is demonstrated in the autopilot setup video here (opens new window) (youtube).


This flight mode selection mechanism is relatively complicated due to the way that PX4 works out which mode should be selected. You may be able to gain some insight from this flow chart.

# Further Information