cold air coming off the aircraft structure as it
prevent the formation of ice. The deicing systems
warms up.
are common to older aircraft. The anti-icing
systems are common to newer aircraft. Both
The shape of the wing may be changed
systems use bleed air to accomplish their
drastically because of the formation of ice or
function.
frost. Control of the aircraft may become difficult
As shown in figures 6-15 and 6-16, the
as the lift characteristics of the wing change.
deicing system uses bleed air to inflate the
Uneven distribution of ice generates an un-
rubber boots along the leading edge of the wing.
balanced aircraft condition. Enough ice to cause
The cells or tubes of the deicer boots are inflated
an unsafe condition can form in a very short
and deflated alternately by pressure and suction,
period of time. Thus, some method of ice removal
causing a wavelike motion, which cracks the
or prevention is necessary.
formed ice and allows it to be carried away by
Presently, there are two methods for elim-
the airstream. The system is pneumatically
inating or preventing ice. One method, deicing,
operated, electrically controlled, and regulated by
employs a mechanical system to break up and
a pressure regulator and relief valve. Suction and
remove the ice after it has formed. The second
pressure gauges provide a means of monitoring
method, anti-icing, uses heated bleed air to
the system operation.
Figure 6-16.-Deicing system.
6-19
