Goodyear Emphasizes Importance Of Aircraft Tire Pressure
Checks
We just got through another weekend,
which is perhaps a good time for a "back to basics" reminder about
the only part of most airplanes that is actually designed to be in
contact with the ground.
Goodyear says aviation tires' design and construction differ
from automobile tires, and though it is important to maintain the
correct pressure in car tires, proper aircraft tire pressure is the
most important factor in aircraft preventive maintenance. As a
result, pilots and maintenance personnel must resist the temptation
to follow the same schedule they would use in checking their cars'
tires to determine that their aircraft tire pressure is
correct.
That's the advice from Goodyear Aviation's Robert Robson. He is
Goodyear's Product Support Manager and regularly teaches aviation
industry authorized inspection classes. Robson brings 10 years of
aviation tire experience to the table. "Aircraft tire pressure
should never be taken for granted," Robson said. "High pressures,
high loads, and the different designs of aircraft tires and wheels
often cause assemblies to lose pressure faster than those for
cars."
He said problems caused by incorrect aircraft tire pressure can
be serious. Overinflated tires can suffer uneven tread wear,
reduced braking traction, increased susceptibility to cutting, in
addition to causing greater stress on wheels and landing gear.
Underinflated tires also can wear unevenly and will experience
increased stress and flex heating, which shortens tire life and can
lead to tire failure.
Robson advises daily aircraft tire pressure checks, preferably
before first flight. "Check pressures when the tires are at ambient
temperatures," he said. "Tire temperatures can increase 200°F
during aircraft operation, and every increase of 5ºF results
in approximately a 1% pressure change." Therefore aircraft tire
pressure should never be reduced when the tires are still hot.
Robson said tires should not be placed in service until they
have been inflated for at least 12 hours after mounting. "All
tires, particularly bias, grow after their initial mounting. The
larger volume of the tire results in a pressure drop, and thus the
tire must be checked and re-inflated if necessary," he said. After
completing the 12-hour stretch, it is highly recommended to perform
a 24-hour diffusion check to ensure the tire/wheel assembly is
holding pressure within the limits of 5% per day, since there are
numerous potential sources of pressure loss within the assembly.
Both of these steps are important to help ensure the tires are not
underinflated before entering service.