3,000-psi hydraulic pressure to the power mechanism.
If one hydraulic systems fails, the other system
supplies enough pressure to operate the mechanism.
If both hydraulic systems fail, the cylinder
disconnects by pulling the MAN FLT CONT (manual
flight control) handle in the cockpit. The controls
work manually through the linkage of the mechanism
to operate the elevators.
The load-feel bungee, shown in figure 9-5,
provides an artificial feel to the control stick. The
bungee acts as a centering device for the elevator
system. Control stick movement compresses the
spring in the bungee. Releasing the control stick
causes the compressed spring to return the stick to
The bungee also adds a gearing effect
between the horizontal stabilizer and the elevators.
nose up condition, the bungee action adds nose up
elevator. With the stabilizer trimmed nose down, the
bungee action adds nose down attitude on the
Horizontal Stabilizer Control System (Single
Various aircraft manufacturers identify the
horizontal stabilizer control system by different
names. On one aircraft, it is called a unit horizontal
tail (UHT) control system. On another aircraft, it is
called the stabilizer control system. Regardless of
the variation in nomenclature, these systems
function to control the aircraft pitch about its lateral
When the stabilizer is trimmed to give an aircraft
Figure 9-5.Elevator power mechanism.