pneumatically controlled canopy hydraulic ac- tuator opens and closes the canopy. A canopy- lock pneumatic actuator moves the canopy to the locked or unlocked position. The canopy is locked in the closed position by locking hooks that engage latches on the cockpit sill. An inflatable rubber seal in the canopy frame forms a pressure- tight enclosure when the canopy is closed and locked. Three rearview mirrors are mounted on the pilot’s forward canopy frame and one on the naval flight officer’s (NFO) forward canopy frame. The canopy can be jettisoned for an emergency on the ground and during the ejection sequence. The clamshell canopy pneumatic system provides normal opening and closing of the canopy. The system is controlled with the canopy control handle at each crew station or with the external canopy control handle on the fuselage left side. Pneumatic pressure from externally serviced reservoirs supply the power for the different modes of canopy operation. The canopy can also be manually opened and closed. A reference mark is painted on the fuselage and canopy, and when the canopy is closed and locked, the marks are aligned. SYSTEM OPERATION The F-14 aircraft uses the clamshell canopy system. This pneumatic system is operated by setting any one of the three canopy control handles, This action positions valves within the pneumatic control module to route pneumatic pressure to or from the system. The modes of operation that can be selected are normal opening mode, holding mode, normal closing mode, boost closing mode, and auxiliary opening mode. The function of all three control handles is the same. Normal Opening Mode Figure 2-2 (a foldout at the end of this chapter) shows a schematic of the F-14 pneumatic canopy system. Setting the pilot canopy control handle to open pulls the lock lockpin and positions valves No. 1,2, and 6 within the control module to direct nitrogen at 325 psi through the C 1 and C3 ports of the module, to the timer check valve, and to the unlock port of the canopy-lock pneumatic actuator. Simultaneously, the shutoff valves in the open and close modules of the canopy hydraulic actuator are vented to the atmosphere through the C5 port of the actuator, through the canopy pneumatic timer, and through valve No. 3 in the control module. The lock port of the canopy-lock pneumatic actuator is vented overboard through the pneumatic timer. The piston of the actuator extends and, by means of a torque tube, cranks, and links, moves the canopy aft to unlock it from the sill locks. When the extending piston reaches the end of its stroke, ball locks engage to hold it in that position. The extended piston also actuates the timer check valve, which directs the 325-psi nitrogen to the C1 port of the canopy hydraulic actuator. The nitrogen that enters the hydraulic actuator acts against the piston of the open transfer cylinder. This pressure, acting against the piston, causes the hydraulic fluid on the opposite side of the piston to extend the ac- tuator. The extending actuator rotates the canopy on the aft hinge to open the canopy. As the ac- tuator extends, fluid displaced from the close side of the actuator acts against the piston of the close transfer cylinder. The nitrogen on the opposite side of this piston is vented overboard through the C2 port of the hydraulic actuator and through valve No. 4 of the control module. Pulling the lock lockpin at the beginning of the opening cycle closes the canopy switch, which provides 28 volts from the essential dc No. 2 bus, through the CAN/LAD CAUTION/EJECT CMD IND circuit breaker, to the canopy caution indicator light on the pilot and NFO caution advisory indicators. Holding Mode The HOLD position stops canopy motion at any desired opening. Valve No. 3 in the control module directs 325-psi nitrogen through the C5 port of the module, through the pneumatic timer, to the C5 port of the hydraulic actuator. The nitrogen that enters the C5 port closes the shutoff valves in the open and close modules. The closed shutoff valves trap hydraulic fluid on the open and close side of the actuator piston, stopping piston travel. Normal Closing Mode Setting the control handle to CLOSE positions valves No. 1, 2, 4, and 5 in the control module 2-2