Figure 11-15.Tire storage rack (varied size tires).
second method uses four or more vent holes that
extend completely through each tire sidewall. They
relieve both pocketed air and air that accumulates in
the cord body by normal diffusion through the inner
tube and tire. Tube tire vent holes are marked with an
aluminum- or white-colored dot.
Tubeless tires have vent holes that penetrate from
the outside of the tire sidewall to the outer plies of the
cord body. They relieve air that accumulates in the
cord body by normal diffusion through the tubeless
tire liner and the tire carcass. Vent holes in tubeless
tires are marked with a bright green dot.
NOTE: Rebuilt tires may not have the vent
holes clearly marked.
The life of a tire, whether mounted or unmounted,
is directly affected by storage conditions. Tires
should always be stored indoors in a dark, cool, dry
room. It is necessary to protect them from light,
Light causes ultraviolet (UV)
damage by breaking down the rubber compounds.
The elements, such as wind, rain, and temperature
changes, also break down the rubber compounds.
Damage from the elements is visible in the form of
surface cracking or weather checking. UV damage
may not be visible. Tires can be protected from light
by painting the storeroom windows. Tires must not
be allowed to come in contact with oils, greases,
solvents, or other petroleum products that cause
rubber to soften or deteriorate. The storeroom should
not contain fluorescent lights or sparking electrical
equipment that could produce ozone.
Tires should be stored vertically in racks and
according to size. See figure 11-15. The edges of the
racks must be smooth so the tire tread does not rest on
a sharp edge.
Tires must never be stacked in
horizontal piles. The issue of tires from the storeroom
should be based on age from the date of manufacture
so the older tires will be used first. This procedure
helps to prevent the chance of deterioration of the
older tires in stock.
There are two types of inspections conducted on
tires. One is conducted with the tire mounted on the
wheel. The other inspection is conducted with the tire
During each daily or special inspection, tires must
be inspected for correct pressure, tire slippage on the
wheel (tube tires), cuts, wear, and general condition.
Tires must also be inspected before each flight for
obvious damage that may have been caused during or
after the previous flight.
Maintaining the correct inflation pressure in an
aircraft tire is essential to safety and to obtain its
maximum service life. Military aircraft inner tubes
and tubeless tire liners are made of natural rubber to
satisfy extreme low-temperature performance
requirements. Natural rubber is a relatively poor air
retainer. This accounts for the daily inflation pressure
loss and the need for frequent pressure checks. If this
check discloses more than a normal loss of pressure,
you should check the valve core for leakage by