The centre keel provides strength for the fuselage and contains the hot air duct. It forms the base of the centre control console and contains hard points for mounting the safety belts. The seatback brace contains hard points for mounting the landing brake actuating mechanism and the fuel selector valve. It also contains a pocket for storing maps, and the control cables pass through it.
The parts for the seat braces, spacers, duct top, and duct sides were laid out on a sheet of 0.25″ thick white, low density, Clark foam.
