How to read airspeed sensor data using MAVROS

I am using MAVROS to communicate between raspberry pi and pixhawk. I want to read the airspeed data on raspberry pi but I couldn’t find any mavros topic for it.

I tried editing the pixhawk code and assigning airspeed value to actuator.control[4] hoping I could read it on raspberry pi by subscribing to the ActuatorControl topic but it’s not working. I get the value from my transmitter channel when I read actuator.control[4] and if I assign the airspeed value to a different index of actuator.control I read only 0 on raspberry pi.

_actuators.control[actuator_controls_s::INDEX_FLAPS] = _airspeed_sub.get().indicated_airspeed_m_s;

Please let me know if there is an other way to make it work.