CHAPTER 3
COMPONENTS
The canopy on modern high-performance aircraft
serves several purposes. It protects the crew, provides
LEARNING OBJECTIVE: Identify compo-
enhanced visibility, and serves as an avenue of escape
nents of the pneumatic canopy system and their
in case of emergency.
function.
The canopy system includes the canopy itself,
This section will cover the canopy and following
plus all the components used in opening and closing
components: canopy hydraulic actuator, canopy-lock
the canopy for normal entrance and exit, as well as
pneumatic actuator, lock actuator restrictor, canopy
those used in jettisoning the canopy during an
pneumatic timer, canopy pneumatic control module,
emergency. Inspection and maintenance of canopy
canopy pneumatic reservoir, pneumatic servicing
actuating systems are important responsibilities of the
charging module, canopy switch, auxiliary pneumatic
AME.
reservoir, unlock shuttle valve, and the lock actuator
Aircraft manufacturers have designed various
check valve.
methods of actuating the canopy. Normal opening and
CANOPY
closing may be done pneumatically (compressed air),
electrically, manually, or hydraulically. Emergency
The canopy is a transparent enclosure for the
opening (jettisoning) is done pneumatically or
cockpit; it consists of two acrylic panels in a metal
explosively.
frame. During normal operation, a pneumatically
In most instances, more than one method is
controlled canopy hydraulic actuator opens and closes
provided for normal opening and closing of the canopy;
the canopy. A canopy-lock pneumatic actuator moves it
thus, if one system fails, the other may be used. The
to the locked or unlocked position. It is locked in the
same holds true for jettisoning the canopy. This chapter
closed position by 14 locking hooks that engage latches
will discuss the pneumatic canopy system on the F-14
on the cockpit sill. An inflatable rubber seal in the
and the frangible escape canopy system on the S-3
canopy is closed and locked. Three rearview mirrors are
aircraft.
mounted on the pilot forward canopy frame; one, on the
naval flight officer (NFO) forward canopy frame. The
DESCRIPTION
canopy can be jettisoned in an emergency on the ground
and during the ejection sequence. Figure 3-1 displays
LEARNING OBJECTIVE: Describe the
the canopy pneumatic systems component locations.
F-14 pneumatic canopy system.
CANOPY HYDRAULIC ACTUATOR
The pneumatic canopy system provides normal
opening and closing of the canopy in the F-14 aircraft.
The canopy hydraulic actuator (fig. 3-1, Item D)
The system is controlled with the canopy control
opens and closes the canopy. It consists of a
handle at each crew station or with the external canopy
double-acting hydraulic cylinder, two transfer
control handle on the fuselage left side. Pneumatic
cylinders, and two hydraulic control modules. The
pressure from externally serviced reservoirs supplies
transfer cylinders transfer pneumatic pressure from the
the power for the different modes of canopy operation.
canopy pneumatic control module to hydraulic power.
The canopy also can be manually opened and closed. A
The hydraulic control modules contain pneumatically
reference mark is painted on the fuselage and canopy.
actuated shutoff valves that hydraulically lock the
When the canopy is closed and locked, the marks are
canopy actuator in any position. When the canopy
aligned.
pneumatic control module is in the neutral position,
Q3-1. What provides the power for the different
flow regulators control actuator speed by permitting
modes of canopy operation?
free flow of hydraulic fluid to the actuator and restricted
flow from the actuator, and thermal relief valves relieve
Q3-2. What is painted on the canopy to provide a
pressure from the double-acting cylinder to the transfer
visual display of being closed and locked?
3-1
