tool, without demounting the tire from the wheel. Make
certain that every valve has a valve cap on it, screwed
on firmly with the fingers. The cap prevents dirt oil and
moisture from getting inside the valve and damaging the
core. It also seals In air and serves as protection in
case a leak develops in the valve core.
accordance with the applicable maintenance manual.
9-10. Ski Maintenance. Maintenance of skis shall be
as specified In the applicable aircraft maintenance
manual and the following paragraphs.
Ski Inspection. It is advisable to examine ski
installations frequently to keep them maintained in
airworthy condition. If shock cord is used to keep the ski
runner in proper trim, periodically examine to assure
that the cord has enough elasticity to keep the runner in
its required attitude and the cord is not becoming loose
or badly frayed. Replace old or weak shock cords.
When other means of restraint are provided, examine
for excessive wear and binding, and replace or repair
when such conditions are found. Examine the points of
cable attachment, both on the ski and the airplane
structure, for bent lugs due to excessive loads having
been imposed while taxiing over rugged terrain, or by
trying to break loose frozen skis. If skis which permit
attachment to the wheels and tires are used, maintain
proper tire pressure, as under inflated tires may push off
the wheels. if appreciable side loads are developed in
landing or taxiing.
Ski Repair. Aluminum tubular members may
have negligible damage of surface scratches and
smooth contour dents not over 1/16 Inch in depth. All
replacement unless otherwise specified in applicable
aircraft maintenance manual. Steel tubular members
may have negligible damage of surface scratches and
small dents not over 0.004 inch in depth. Repairable
damage shall consist of straightening slight bends and
rewelding existing welds.
9-11. Float Maintenance. In order to maintain floats in
an airworthy condition, frequent inspections should be
made because of the rapidity with which corrosion takes
place on aluminum alloy metal parts, particularly when
the aircraft Is operated in salt water. Examine metal
floats and all metal parts on wooden or fiberglass floats
for corrosion and take corrective action in accordance
with the applicable aircraft maintenance manual. All
maintenance of floats shall be as specified in the
applicable aircraft maintenance manual.
9-12. Flight Controls. The flight control surfaces are
hinged or movable airfoils designed to change the
attitude of the aircraft during flight. Maintenance of
flight controls shall be accomplished by replacing worn,
damaged, or defective components, adjusting rigging
maintenance to the system.
Types. Ailerons, elevators, the rudder, flaps,
and trim tabs are the common types of flight controls.
Each is explained in the following paragraphs.
(1) Ailerons. The motion of the aircraft about
the longitudinal axis is called rolling or banking. The
ailerons, as shown in figure 9-13, are used to control this
movement. The ailerons form a part of the wing and are
located in the trailing edge of the wing toward the tips.
Ailerons are the movable surfaces of an otherwise fixed-
surface wing. The aileron is in neutral position when it is
streamlined with the trailing edge of the wing.
(2) Elevators. When the nose of an aircraft is
raised or lowered, it is rotated about its lateral axis.
Elevators are the movable control surfaces that cause
this rotation, as shown in figure 9-14. They are normally
hinged to the trailing edge of the horizontal stabilizer.
The elevator can be moved either up or down. If the
elevator is rotated up, it decreases the lift force on the
tail causing the tail to lower and the nose to rise. If the
elevator is rotated downward, it increases the lift force
on the tail, causing it to rise and the nose to lower.
Lowering the aircraft's nose increases forward speed,
and raising the nose decreases forward speed.
(3) Rudder. Turning the nose of the aircraft
causes the aircraft to rotate about its vertical axis.
Rotation of the aircraft about the vertical axis is called
yawing. This motion is controlled by using the rudder as
shown In figure 9-15.
(4) Flaps. Flaps are high-lift devices attached
to the trailing edge of the wing. The flap is controlled
from the cockpit, and when not in use fits smoothly into
the lower surface of each wing. The use of flaps
increases the camber of a wing and therefore the lift of
the wing, making it possible for the speed of the aircraft
to be decreased without stalling. This also permits a
steeper gliding angle to be obtained such as in the
landing approach. Flaps are primarily used during
takeoff and landing. Figure 9-16 shows various types of
flaps used on aircraft.