Three Indicators air speed (Kelvin) ser.nos. K1340, K1333 and K1309

The Pressure Head (1956-41) extends through a hole in the forward part of the aircraft clear of the slipstream, and contains both the Pitot and Static heads. The air pressure in the Pitot head activates the Air Speed Indicator, which really measures pressure though it is calibrated for speed.

The pitot head is heated to prevent condensation and subsequent freezing of the atmospheric moisture, which would otherwise cause a blocking of the pressure inlet.

This type of Pressure Head is used in conjunction with A.S.Is in Comet, Argosy and Trident aircraft.