Get Altimeter Height

[pet93]

Hi, I'm attempting to retrieve altimeter height in order to make an height control. I subscribed EVENT_FLIGHT_DATA (by copying default code) but height is fixed to 0, while other parameters as ground speed, battery percentage, wifi, change! How can I obtain that measure? I also tried with pos_z in mvo data, but even though results are coherent with the motion, values are completely wrong. Thank you in advance