British Aircrew P4-Type and P4B-Type Oxygen Masks
Stores Ref: believed to be 6D/??
This special oxygen mask was only used in the RAF for the Folland Gnat.
A unique design where the communications contacts are combined within the oxygen connector, making one action to conenct both services, but the loss of intercom was also used as a warning that the oxygen conencttion had become loose.
It's special hose required the G-Type or Mk2A helmet to have a special headset wiring harness installed to usitlise the microphone socket as a headphone socket. The seat was equipped with a special combined oxygen and mic / tel PEC.
The P4B-Type was identical to the P4-Type, apart from being designed for the smaller microphone.
RAF Resources
AP1182, Volume 1, Section 1, Chapter 9, (AL 69, Nov 1961)
This cross sectioned drawing shows the main components of the P4-Type oxygen mask. It's clear to see how the communications wires are taped to the sides of the oxygen hose.
AP109B-0200-1 (March 1970)
Quote:
Helmet, mask and tube
75. The Integral Protective Helmet, Mk2A flying helmet, a helmet connector and an oxy/mic/tel Type P4 mask is used (fig. 29). The lower plugs of the mask tube and seat hose each incorporate four annular rings to make the mic/tel connections.Mask tube connection to P.E.C.
76. Two external pins are fitted to the mask tube plug and these pins must be inserted fully into the socket slots of the P.E.C. before electrical contact is made with contact blades in the socket....
78. The plug and socket are so designed that mic-tel communication is broken before oxygen leakage can occur due to partial disconnection; this joint should be checked immediately in the event of communication failure.
AP109B-0200 Fig 27 (March 1970)
This image demonstrates the combined oxygen and mic / tel system as a whole, as used in the Gnat aircraft.
