diff --git a/docs/en/flight_modes_fw/altitude.md b/docs/en/flight_modes_fw/altitude.md index d35cf8d4a32..f486de43a3a 100644 --- a/docs/en/flight_modes_fw/altitude.md +++ b/docs/en/flight_modes_fw/altitude.md @@ -57,6 +57,21 @@ The mode is affected by the following parameters: | [FW_T_CLMB_R_SP](../advanced_config/parameter_reference.md#FW_T_CLMB_R_SP) | Max climb rate setpoint. Default: 3 m/s. | | [FW_T_SINK_R_SP](../advanced_config/parameter_reference.md#FW_T_SINK_R_SP) | Max sink rate setpoint. Default: 2 m/s. | +## MAVLink Commands + +The following commands are relevant to this mode: + +- [MAV_CMD_DO_CHANGE_SPEED](https://mavlink.io/en/messages/common.html#MAV_CMD_DO_CHANGE_SPEED) — Sets the cruise airspeed for centred throttle stick. + + This requires an airspeed sensor. + Only the airspeed speed type is handled (`param1` must be `0`); other speed types are ignored. + At centered throttle the vehicle holds the commanded airspeed (`param2`) if a positive value is set (non-positive values are ignored). + The value is constrained between [FW_AIRSPD_MIN](../advanced_config/parameter_reference.md#FW_AIRSPD_MIN) and [FW_AIRSPD_MAX](../advanced_config/parameter_reference.md#FW_AIRSPD_MAX), and defaults to [FW_AIRSPD_TRIM](../advanced_config/parameter_reference.md#FW_AIRSPD_TRIM) if no airspeed has been commanded. + Deflecting the throttle stick scales the airspeed toward `FW_AIRSPD_MIN` (back) or `FW_AIRSPD_MAX` (forward) around this value. + The commanded airspeed resets to `FW_AIRSPD_TRIM` on every flight mode change. + +Note, other commands may be supported. +