Section 4

Canopy Controls and Circuit

The canopy circuit consists of a Dowty Electro Hydraulic switch, directing hydraulic pressure to the canopy ram in the cockpit. The selector consists of two circuits. (1) Open circuit and (2) Close circuit. Activation of either open or close can be facilitated via a switch concealed behind panel 75P on the outer skin, or from a selector handle attached to the port seat pan in the cockpit. Both internal and external selector switches are wired in parallel, sharing a common power feed from the emergency services bus bar, hence canopy operation can only be performed with the service battery installed. Wiring to the Dowty selector crosses the transport joint port and consists of circuits MB11, MB12 and MB13N (being the earth to E5) (main equipment Bay, port). All three circuits have been identified by means of continuity from the terminating block on the port cockpit sloping bulkhead and re-joined to the Dowty selector wiring and traversing the transport joint port. All wiring has been crimped, shrink wrapped, and tagged. The canopy circuit is now functioning correctly along with the claxon warning, facilitating entry into the cockpit. Fluid is currently directed into the canopy lines from connections in the gun pack bay. The hydraulic circuit will be re-connected later, when the services circuit hydraulic lines are re-installed into the airframe and pressurized.

An example of a Dowty Electro Hydraulic switch. Access panel 26P