The RC Allen RCA 22 series of vacuum horizon have an air driven precision gyroscope to present the pilot with pitch and roll information through a full 360°. A pictoral presentation leads to faster interpretation of aeroplane attitude. The 22 series of instruments meets or exceeds FAA TSO C4c.
Through the years the RCA 22 series of instrument has proved itself to be one of the most reliable instruments ever manufactured and has been standard equipment on many general aviation aeroplanes produced over the last 40 years.
Versions available with fail flag, or lighting (14 and 28v).