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The triggers element consists of a list of trigger. Each trigger object can contain the following elements. Triggers enable the application to act on a change of a simvar. For example to trigger an alternate of an encoder.

Element Mandatory Description
simvar ✅ The simvar to monitor
trigger_type ✅ The type of the trigger
trigger_index ❎ The index of the element to trigger
condition ❎ The condition when the trigger_type is set to condition


Th trigger_type can be set to encoder, condition or condition-file. The 2 condition types are explained in the advanced section. The encoder type can be used to trigger the alternate mode of an encoder.


Most autopilot stacks have a single wheel to control either the vertical speed or the speed itself, depending whether it's in FLC or VS mode. To have a single encoder control both, an alternate must be added so the encoder can sent both events. To automatically switch between the alternates a trigger is made to monitor the AUTOPILOT_VERTICAL_HOLD. When AUTOPILOT_VERTICAL_HOLD is true the encoder is set to alternate, otherwise it's in the default setting.

  "trigger_type": "encoder",
  "trigger_index": 5
  "index": 5,
  "event_up": "AP_SPD_VAR_INC",
  "event_down": "AP_SPD_VAR_DEC",
  "alternate_event_up": "AP_VS_VAR_INC",
  "alternate_event_down": "AP_VS_VAR_DEC"