AIRCRAFT SYSTEMS II
1.0 ICE AND RAIN PROTECTION SYSTEM:
1.1 INTRODUCTION:
Rain, snow, and ice are transportation’s longtime enemies. Flying has added a new dimension, particularly
with respect to ice. Under certain atmospheric conditions, ice can build rapidly on airfoils and air inlets.
On days when there is visible moisture in the air, ice can form on aircraft leading edge surfaces at
altitudes where freezing temperatures start. Water droplets in the air can be supercooled to below
freezing without actually turning into ice unless they are disturbed in some manner. This unusual
occurrence is partly due to the surface tension of the water droplet not allowing the droplet to expand and
freeze.
However, when aircraft surfaces disturb these droplets, they immediately turn to ice on the aircraft
surfaces.
▪ RAIN – Rain is liquid precipitation; water droplets falling from the sky; Raindrops fall to
Earth when clouds become saturated, or filled, with water droplets.
▪ SNOW – Snow comprises individual ice crystals that grow while suspended in the
atmosphere usually within clouds and then fall, accumulating on the ground where they
undergo further changes.
▪ ICE - Ice is water frozen into a solid state, typically forming at or below temperatures of 0
degrees Celsius or 32 degrees Fahrenheit. Depending on the presence of impurities such as
particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-
white color.
The two types of ice encountered during flight are clear and rime.
Clear ice forms when the remaining liquid portion of the water drop flows out over the aircraft surface,
gradually freezing as a smooth sheet of solid ice. Formation occurs when droplets are large, such as in
rain. Clear ice is hard, heavy, and tenacious. Its removal by deicing equipment is especially difficult.
Rime ice forms when water drops are small, such as those in stratified clouds or light drizzle. The liquid
portion remaining after initial impact freezes rapidly before the drop has time to spread over the aircraft
surface. The small frozen droplets trap air giving the ice a white appearance. Rime ice is lighter in weight
than clear ice and its weight is of little significance. However, its irregular shape and rough surface
decrease the effectiveness of the aerodynamic efficiency of airfoils, reducing lift and increasing drag.
Rime ice is brittle and more easily removed than clear ice.
Ice or frost forming on aircraft creates two basic hazards:
1. The resulting malformation of the airfoil that could decrease the amount of lift.
2. The additional weight and unequal formation of the ice that could cause unbalancing of the
aircraft, making it hard to control.
Enough ice to cause an unsafe flight condition can form in a very short period of time, thus some method
of ice prevention or removal is necessary. Figures below shows ice on leading edges.
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https://www.coursehero.com/file/178777384/AIRCRAFT-SYSTEMS-II-ICE-AND-RAIN-PROTECTION-SYSTEMdocx/
, Icing Effects:
Below is a list of effects of icing on aircrafts. They include:
▪ Ice buildup increases drag and reduces lift.
▪ It causes destructive vibration.
▪ Hampers true instrument readings.
▪ Control surfaces become unbalanced or frozen.
▪ Fixed slots are filled and movable slots jammed.
▪ Radio reception is hampered.
▪ Engine performance is affected.
Ice and snow have a direct impact on the safety of flight. Not only because of degraded lift, reduced
takeoff performance, and/ or maneuverability of the aircraft, but when chunks break off, they can also
cause engine failures and structural damage. Fuselage aft-mounted engines are particularly susceptible to
this foreign object damage (FOD) phenomenon. Wing mounted engines are not excluded. Figure below
summarizes the effects of icing on an aircraft.
The ice and rain protection systems used on aircraft keep ice from forming on the following airplane
components:
▪ Wing leading edges
▪ Horizontal and vertical stabilizer leading edges
▪ Engine cowl leading edges
▪ Propellers
▪ Propeller spinner
▪ Air data probes
▪ Flight deck windows
This study source was downloaded by 100000858663287 from CourseHero.com on 12-09-2022 16:20:47 GMT -06:00
https://www.coursehero.com/file/178777384/AIRCRAFT-SYSTEMS-II-ICE-AND-RAIN-PROTECTION-SYSTEMdocx/
1.0 ICE AND RAIN PROTECTION SYSTEM:
1.1 INTRODUCTION:
Rain, snow, and ice are transportation’s longtime enemies. Flying has added a new dimension, particularly
with respect to ice. Under certain atmospheric conditions, ice can build rapidly on airfoils and air inlets.
On days when there is visible moisture in the air, ice can form on aircraft leading edge surfaces at
altitudes where freezing temperatures start. Water droplets in the air can be supercooled to below
freezing without actually turning into ice unless they are disturbed in some manner. This unusual
occurrence is partly due to the surface tension of the water droplet not allowing the droplet to expand and
freeze.
However, when aircraft surfaces disturb these droplets, they immediately turn to ice on the aircraft
surfaces.
▪ RAIN – Rain is liquid precipitation; water droplets falling from the sky; Raindrops fall to
Earth when clouds become saturated, or filled, with water droplets.
▪ SNOW – Snow comprises individual ice crystals that grow while suspended in the
atmosphere usually within clouds and then fall, accumulating on the ground where they
undergo further changes.
▪ ICE - Ice is water frozen into a solid state, typically forming at or below temperatures of 0
degrees Celsius or 32 degrees Fahrenheit. Depending on the presence of impurities such as
particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-
white color.
The two types of ice encountered during flight are clear and rime.
Clear ice forms when the remaining liquid portion of the water drop flows out over the aircraft surface,
gradually freezing as a smooth sheet of solid ice. Formation occurs when droplets are large, such as in
rain. Clear ice is hard, heavy, and tenacious. Its removal by deicing equipment is especially difficult.
Rime ice forms when water drops are small, such as those in stratified clouds or light drizzle. The liquid
portion remaining after initial impact freezes rapidly before the drop has time to spread over the aircraft
surface. The small frozen droplets trap air giving the ice a white appearance. Rime ice is lighter in weight
than clear ice and its weight is of little significance. However, its irregular shape and rough surface
decrease the effectiveness of the aerodynamic efficiency of airfoils, reducing lift and increasing drag.
Rime ice is brittle and more easily removed than clear ice.
Ice or frost forming on aircraft creates two basic hazards:
1. The resulting malformation of the airfoil that could decrease the amount of lift.
2. The additional weight and unequal formation of the ice that could cause unbalancing of the
aircraft, making it hard to control.
Enough ice to cause an unsafe flight condition can form in a very short period of time, thus some method
of ice prevention or removal is necessary. Figures below shows ice on leading edges.
This study source was downloaded by 100000858663287 from CourseHero.com on 12-09-2022 16:20:47 GMT -06:00
https://www.coursehero.com/file/178777384/AIRCRAFT-SYSTEMS-II-ICE-AND-RAIN-PROTECTION-SYSTEMdocx/
, Icing Effects:
Below is a list of effects of icing on aircrafts. They include:
▪ Ice buildup increases drag and reduces lift.
▪ It causes destructive vibration.
▪ Hampers true instrument readings.
▪ Control surfaces become unbalanced or frozen.
▪ Fixed slots are filled and movable slots jammed.
▪ Radio reception is hampered.
▪ Engine performance is affected.
Ice and snow have a direct impact on the safety of flight. Not only because of degraded lift, reduced
takeoff performance, and/ or maneuverability of the aircraft, but when chunks break off, they can also
cause engine failures and structural damage. Fuselage aft-mounted engines are particularly susceptible to
this foreign object damage (FOD) phenomenon. Wing mounted engines are not excluded. Figure below
summarizes the effects of icing on an aircraft.
The ice and rain protection systems used on aircraft keep ice from forming on the following airplane
components:
▪ Wing leading edges
▪ Horizontal and vertical stabilizer leading edges
▪ Engine cowl leading edges
▪ Propellers
▪ Propeller spinner
▪ Air data probes
▪ Flight deck windows
This study source was downloaded by 100000858663287 from CourseHero.com on 12-09-2022 16:20:47 GMT -06:00
https://www.coursehero.com/file/178777384/AIRCRAFT-SYSTEMS-II-ICE-AND-RAIN-PROTECTION-SYSTEMdocx/
