17.5* Flashcards
What are the two main ice protection systems?
. Electrical de icing
. Fluid anti icing
What type of anti icing systems do piston type engines usually use?
Fluid anti icing
What fluid does fluid anti icing system use?
Alcohol based fluid - iso propyl alcohol
How does fluid anti icing work?
A pump that’s monitored by a rheostat injects filtered fluid through a fixed nozzle on each engine into a U shaped slinger ring on each prop. The fluid is then forced by centrifugal force onto grooved anti icing rubber boots
What must you ensure with the fluid discharge nozzle and the slinger ring?
That they are in proper alignment
What does a flow test do?
It simultaneously sends out the fluid on each engine to check that the delivery distribution rate to each engine is balanced.
When can a functional test be carried out?
When the engines are running
How is cleaning of the fluid anti ice systems done?
By flushing a maxi tube of 95% methylated sprits and 5% distilled water. Then the blades are washed with methylated spirt or warm soapy water. And filter cleaned periodically with methylated spirit.
On electrical de icing boots/ mats where are the elements placed?
Heating boots/ mats containing electrical elements are bonded to the inner 3rd of each propeller blade
A single element boot/ mat will have how many electrical leads?
Two electrical leads
A twin element boot/ mat will have how many electrical leads?
Three leads - 2 live and 1 earth
How do electrical mats actually work?
They use cyclic heating which allows a thin layer of ice to form on the heater mat. The ice then melts where it contacts the mat causing it to loosen and be dispersed by centrifugal force
What is the fast cycle and on what temperatures is it used?
2 minutes and temps from 10 to -6 degrees c
What is the slow cycle and on what temperatures is it used?
6 minutes and temperatures below -6 degrees c
When doing a function test what will indicate the current consumption?
The ammeter readings in the cockpit
