ANTI-ICE AND DE-ICE SYSTEMS
61-00-36
Page 7-4
Rev. 2 Feb/17
Propeller Owner's Manual
136
2. System Description
A. De-ice System
NOTE: Because of the wide variances of various de-ice
systems, the following description is general in
nature. Consult the airframe manufacturer’s manual
for a description of your specific de-ice system and
controls.
(1) The de-ice system is controlled by the pilot via a cockpit
control switch. This switch applies electrical power to the
de-ice system, which will operate as long as the switch
is in the ON position. Depending upon the system,
another set of cockpit controls may be available. One
of these controls is a mode selector, which permits the
pilot to select two cycling speeds, for heavy or light icing
conditions. Some systems on twin engine aircraft have a
switch which provides a full de-ice mode, which permits
the pilot to de-ice both propellers simultaneously. This
switch may only be used for short periods and is used
when ice builds up on the propeller before the system is
turned on.
(2) An ammeter, which indicates current drawn by the
system, is normally located near the de-ice system
switches. This meter may indicate total system load,
or a separate meter may be supplied for each propeller.
(3) A timer, which is turned off and on by the cockpit control,
is used to sequence the de-ice system. This timer
turns the de-ice system on and off in proper sequence,
controlling the heating interval to each propeller for
even de-icing.
(4) A brush block, which is mounted on the engine
immediately behind the propeller, supplies electrical
current to the de-ice boot on each propeller blade via
a slip ring. The slip ring is normally mounted on the
spinner bulkhead.
(5) When the pilot places the de-ice system cockpit control
switch in the ON position, the system timer begins to
operate. As the timer sequences, power is delivered to
a power relay. The power relay delivers high current to
the brush block and slip ring. Each propeller is de-iced in
turn by the timer.
