M17.5 Ice protection

Question 1

What are the two main ice protection methods??

Answer 1

. Fluid anti icing system
. Electrical de icing systems

Question 2

Where is fluid de icing used?

Answer 2

Only on piston engines aircraft

Question 3

Why is fluid de icing not used on gas turbine engines?

Answer 3

As it could contaminate the compressor blades of gas turbine engines - not appropriate for turbo prop

Question 4

What alcohol is used to prevent ice formation?

Answer 4

ISO- propyl alcohol

Question 5

How does a fluid de icing system work?

Answer 5

A pump c9ntrolled in cockpit injects filtered fluid through a fixed nozzle on ECU engine into a U shaped slinger ring on each propeller. Then the fluid is forced by centrifugal force onto grooved anti icing boots

Question 6

What are the disadvantages of fluid anti icing?

Answer 6

. Weight of fluid to be carried
, the amount of fluid must be constantly monitored
. The system must be operated before icin* occurs
. It is not able to removed impacted ice ince it has formed

Question 7

For fluid de icing, what must you ensure for the slinger ring?

Answer 7

the alignment of fluid discharge nozzle with the slinger ring

Question 8

What test must you do on a multi engine aircraft that uses fluid anti icing?

Answer 8

A flow test -
Simultaneously in each engine to check that the delivery distribution rate to each engine is balanced

Question 9

When must functional tests be done?

Answer 9

When the engines are running

Question 10

How can you clean the fluid anti icing system?

Answer 10

. By flushing through a mixture that consist of 95% methylated spirits and 5% distilled water

Question 11

How are the blades cleaned with fluid anti icing?

Answer 11

Washed with methylated spirt or warm soapy water

Question 12

What is the system filter in fluid anti icing cleaned?

Answer 12

Cleaned periodically using methylated spirt

Question 13

Where are heating boots/ mats on electrical de icing boots??

Answer 13

The electrical elements are bonded to the inner third of each prop blade

Question 14

How many electrical leads will a single element boot have? Compared to a twin element?

Answer 14

. Single element - 2 leads
. Twin element - 3 leads (2 live and 1 earth)

Question 15

How does the ice go away using electrical de ice?

Answer 15

The ice melts where it contacts the mat causing it to loosen and dispersed by centrifugal force

Question 16

What is the fast cycle for electrical de icing?

Answer 16

. 2 mins at a temp from +10 to -6 degrees c

Question 17

What is the slow cycle for electrical de icing?

Answer 17

. 6 minutes at temperatures below -6 degrees c

Question 18

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