Chapter 3: Ice & Rain Protection

Question 1

hazards of ice forming on aircraft

Answer 1

1) destroy lift
2) additional weight (unbalance)

Question 2

types of ice

Answer 2

1) clear ice
2) rime ice

Question 3

how does clear ice form?

Answer 3

water droplets are large (rain), freeze as smooth sheet of ice

Question 4

how does rime ice form?

Answer 4

water droplets are small (light drizzle), freeze in irregular shape and rough surface

Question 5

rime ice appearance

Answer 5

white colour (air trapped in ice)

Question 6

difference in clear and rime ice

Answer 6

clear ice: hard to remove (heavy and hard)

rime ice: lighter in weight

Question 7

methods to prevent/control ice formation

Answer 7

1) heating with hot air / electrical
2) breaking ice with boots
3) chemical

Question 8

anti-ice vs de-ice

Answer 8

anti-ice: prevent ice forming
de-ice: remove ice after accumulate

Question 9

how does wing anti ice system work?

Answer 9

bleed air in routed to wing leading edge from engine compressor at 41 PSI

Question 10

what is the operating temperature of wing anti ice system?

Answer 10

140 F

Question 11

how does thermal electric anti icing work?

Answer 11

current flows through conductive element that produces heat

Question 12

components that uses electric anti icing

Answer 12

1) pitot probe
2) AOA sensor
3) engine pressure & temp sensors
4) windshields

Question 13

where is chemical anti icing used?

Answer 13

leading edge of wings, stabilisers, windshields, propellers

Question 14

how does chemical anti icing work?

Answer 14

anti-freeze solution flows through mesh screen of leading edges which prevents ice from forming

solution depresses waters freezing point

Question 15

how does chemical de icing work?

Answer 15

antifreeze solution breaks bond between ice and airframe

Question 16

ways to remove rain from windshield

Answer 16

1) wipers
2) chemical rain repellent
3) hydrophobic surface seal coating

Question 17

pressure threshold for deicing boots

Answer 17

17 psi