are made up of the following components: canopy
caution light on the cockpit left digital display
indicator, master caution light on the left-hand
advisory and threat warning indicator panel, and
the maintenance code display on the nosewheel
well digital display indicator.
Learning Objective: Identify the canopy
normal mode of operation to include the
manual backup mode.
The canopy is operated electrically by the
external or internal canopy control switches in the
normal control mode. The canopy can also be
operated manually in the backup manual control
mode if electrical power is not available.
NORMAL CONTROL MODE
The canopy may be operated with the external
canopy control switch. To open the canopy, the
switch is held in the OPEN position. The canopy
stops automatically when the full open position
is reached. To close the canopy, the switch is held
in the CLOSE position until the canopy closes,
moves full forward, and locks. The canopy stops
automatically when the closed and locked position
is reached. Motion may be stopped at any point
during opening or closing by releasing the switch.
The switch returns to the HOLD position when
To open the canopy internally with weight on
the wheels, the internal canopy control switch is
set to OPEN and released. The switch is
magnetically held in the OPEN position until the
canopy raises to full open and stops. The switch
then returns to HOLD. Canopy motion may be
stopped at any point during canopy opening by
manually setting the switch to the HOLD position,
which overrides the magnetic holding coil. The
internal canopy control switch opening circuit is
equipped with a weight-off-wheels relay that de-
energizes the magnetic holding coil when the
aircraft is in a weight-off-wheels condition. With
the holding coil de-energized, the switch must be
manually held to the OPEN position when
opening the canopy.
When the canopy closes, moves full forward,
and locks, the No. 4 right canopy latch depresses
t h e c a n o p y p o s i t i on
Simultaneously, the canopy actuator arm rotates
overcenter and depresses the canopy locked switch
plunger. Depressing both switch plungers causes
the master caution light and the canopy display
on the left digital display indicator to extinguish,
indicating the canopy is fully closed and locked.
If both switches are not fully depressed or a failure
occurs in either switch, the master caution and
canopy caution indicators will remain illuminated.
If both switch plungers are not depressed within
15 seconds, the canopy switches disagree and the
maintenance code (889) will be displayed on the
nosewheel well digital display indicator.
Electrical inputs supplied to the canopy
actuator are transformed into mechanical motion
used to raise and lower the canopy. The actuator
is equipped with an up-travel-limit switch, which
automatically interrupts power to the actuator
when the full open position is reached. With no
aircraft generator power or external power
applied, a utility battery supplies power for
at least five open and close cycles of the canopy.
On some F/A-18 aircraft, a logic circuit in
the battery and charger unit secures the
canopy control power when the battery voltage
drops below 19±1 volts.
Due to decreased battery capacity at low
temperatures, canopy operation using battery
power is not recommended when ambient tem-
perature is below 0°F. Under these conditions,
external electrical power should be used. When
external power is not available, the canopy can
be operated using the backup manual control
To further understand how the opening and
closing cycles function, refer to figure 2-9.
BACKUP MANUAL CONTROL MODE
The backup manual control mode is used to
open and close the canopy when utility battery
power is low, internal or external electrical power
is not available, or a failure has occurred in the
canopy actuation control system.
The canopy actuator manual drive unit is
operated from inside the cockpit by using the
internal manual canopy opening handle. The
handle is removed from its stowage receptacle and
clip, and then it is inserted into the crank socket.
The handle is turned 70±1 turns clockwise to
close the canopy or counterclockwise to open the
canopy. The internal manual canopy opening
handle shaft assembly mechanically links the drive
unit to the canopy actuator. By operating the drive
unit internally or externally, mechanical motion
is transferred through the shaft assembly to the