manufacturers refer to them as dive brakes, others
selector valve solenoids (solenoids A and B). This
call them dive flaps. On some aircraft, they are
action connects hydraulic pressure to the actuator
on the sides or bottom of the fuselage; on others
extend side and connects the return to the actuator
they attach to the wings. Regardless of their
retract side. Any desired brake position may be
location, speed brakes serve the same purpose on
attained and will be held by a hydraulic lock
all aircraft--they keep the speed from building
within the selector valve. The speed brake out
warning light illuminates when either the left or
up too high in dives. They can also slow down
the speed of aircraft preparing to land. Speed
right speed brake is not fully retracted. The
warning light circuit completion is through either
brakes have electrical control and hydraulic
operation. Figure 4-19 shows a typical speed brake
the left or right speed brake retract position
system, and you should refer to it while reading
switch.
this section.
NOTE: Figure 4-19 shows the speed brake
EXTENSION. --Extension of the speed
control switch being held in the OUT position.
This allows hydraulic pressure to port to the
brakes is done by placing the speed brake control
switch (located on the throttle lever grip) to the
extend side of the speed brake actuators, forcing
OUT position. The OUT position is a momentary-
the speed brakes to the extend position.
contact position, the switch being spring loaded
to return to STOP when released. Holding the
RETRACTION. --In normal operation, the
speed brakes retract by moving the speed
control switch in the OUT position energizes both
Figure 4-19.-Speed brake system.
4-24
