CHAPTER 2

ELECTRICALLY OPERATED CANOPY SYSTEM

Chapter Objective: Upon completion of this chapter, you will have a working knowledge of the electrically operated canopy system and its components to include normal and emergency operation procedures.

As you know, the canopy system provides an access for the aviator to enter and exit the cockpit. It also provides protection from the elements. We will use the F/A-18C canopy system to discuss a typical electrically operated canopy system (fig. 2-1).

CANOPY SYSTEM

Learning Objective: Recognize the components of the canopy system.

Under normal conditions, the canopy is electrically operated and controlled by either the internal canopy control switch in the cockpit or the external canopy control switch, as shown in figures 2-2 and 2-3. A manual backup control mode operates the canopy when utility battery power is low, internal or external electrical power is not available, or the actuation control system has failed. The emergency canopy jettison system jettisons the canopy during emergencies and ejection.

SYSTEM COMPONENTS

You need to be familiar with the system components to enhance your understanding of the system's operation. Therefore, the following major components are described.

Canopy

The formed-stretched acrylic canopy is mounted in a metal frame. A canopy unlatch thruster and two rocket motors and related ballistic components are mounted on the canopy for emergency jettison. An index pin, a control cam, and three latches are mounted on each side of the canopy frame.

Canopy Pressure Seal

An inflatable canopy pressure seal is located around the canopy arch, along the side frames, and across the canopy deck. When the seal is inflated by the air-conditioning system, the canopy is sealed to the fuselage and windshield arch, allowing the cockpit to be pressurized. A noninflatable weather seal is located parallel to and outboard of the pressure seal. When the pressure seal is deflated, the weather seal prevents entry of water into the cockpit.

Canopy Actuator

The canopy actuator is located behind the aircraft ejection seat on the canopy deck and functions to open and close the canopy. A thermal protection device is provided in the actuator that will automatically interrupt power to the actuator when an overheat condition exists. It will automatically reset within 60 seconds after removal of the overheat condition.

The mechanical components of the canopy actuation system consist of the canopy actuator and the canopy actuation connecting link, which

Figure 2-1.-Electrically operated canopy.

Figure 2-2.-External canopy control switch.

Figure 2-3.-Internal canopy control switch.

is attached to the canopy unlatch thruster, as shown in figures 2-4 and 2-5.

Canopy Actuator Manual Drive Unit

The canopy actuator manual drive unit is located in the cockpit under the left canopy

sill. It is used to manually raise and lower the canopy.

The internal manual canopy opening handle is located on the canopy actuator manual drive unit. The handle is used to operate the drive unit from inside the cockpit. The opening handle shaft assembly is located between the canopy actuator manual drive unit and the canopy actuator. The

Figure 24.-Canopy actuator.

shaft assembly provides a mechanical link between the drive unit and the canopy actuator. (See fig. 2-6.)

The canopy external manual drive receptacle is mounted flush with the fuselage skin below the left canopy sill. The drive receptacle is used to operate the drive unit from outside the cockpit with the aid of a 3/8-inch drive tool. (See fig. 2-7.)

Canopy Control Switches

Two canopy control switches are provided for normal electrical operation of the canopy. The external canopy control switch is located inside the external electrical power receptacle door. (See fig. 2-2.) The internal canopy control switch is located in the cockpit under the right canopy sill. (See fig. 2-1.)