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Aviation Structural Mechanic E1&C - How airplanes are built and how to maintain them | Next
Electrically operated canopy |
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 com-
ponents 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 cock-
pit.
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 con-
dition.
The mechanical components of the canopy
actuation system consist of the canopy actuator
and the canopy actuation connecting link, which
2-1
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