Icing

Question 1

In general, icing is

a) Any deposit of ice forming on an object.

b) Deposits of ice at least 1⁄4 inch thick on any airfoil.

c) Deposits of ice that can be identified as rime or clear, not classified as mixed.

Answer 1

A) Any deposit of ice forming on an object.

Question 2

Supercooled water can exist as large drops known as supercooled large drops (SLDs). These are common in

a) Freezing fog and ice fog situations.

b) Freezing rain and hail situations.

c) Freezing rain and freezing drizzle situations.

Answer 2

C) Freezing rain and freezing drizzle situations.

Question 3

Why do aircraft collect ice when they pass through a liquid cloud or precipitation composed of supercooled drops?

a) Ice crystals collect on the airframe when temperatures are below freezing.

b) Supercooled water will readily freeze if sufficiently agitated.

c) Water droplets will readily freeze when sufficiently agitated.

Answer 3

B) Supercooled water will readily freeze if sufficiently agitated.

Question 4

What are the three types of structural icing?

a) Rime, clear, and mixed.

b) Intake, airfoil, and pitot.

c) Leading edge, intake, and prop (rotor).

Answer 4

A) Rime, clear, and mixed.

Question 5

Rime ice is

a) Rough, milky, and opaque ice formed by the instantaneous freezing of small, supercooled water droplets after they strike the aircraft.

b) A glossy, clear, or translucent ice formed by the relatively slow freezing of large, supercooled water droplets.

c) A mix of clear and glazed ice.

Answer 5

A) Rough, milky, and opaque ice formed by the instantaneous freezing of small, supercooled water droplets after they strike the aircraft.

Question 6

Rime ice can pose a hazard because

a) It tends to form horns near the top and bottom of the airfoil’s leading edge, which greatly affects airflow.

b) It can spread over more of the airframe’s surface and is difficult to remove than clear ice.

c) Its jagged texture can disrupt an aircraft’s aerodynamic integrity.

Answer 6

C) Its jagged texture can disrupt an aircraft’s aerodynamic integrity.

Question 7

Clear (or glaze) ice is

a) Rough, milky, and opaque ice formed by the instantaneous freezing of small, supercooled water droplets after they strike the aircraft.

b) A glossy, clear, or translucent ice formed by the relatively slow freezing of large, supercooled water droplets.

c) A mix of clear and glazed ice.

Answer 7

B) A glossy, clear, or translucent ice formed by the relatively slow freezing of large, supercooled water droplets.

Question 8

Clear ice can pose a hazard because

a) It tends to form horns near the top and bottom of the airfoil’s leading edge, which greatly affects airflow.

b) It can spread over more of the airframe’s surface and is difficult to remove than rime ice.

c) Its jagged texture can disrupt an aircraft’s aerodynamic integrity.

Answer 8

A) It tends to form horns near the top and bottom of the airfoil’s leading edge, which greatly affects airflow.

Question 9

Mixed ice is

a) Rough, milky, and opaque ice formed by the instantaneous freezing of small, supercooled water droplets after they strike the aircraft.

b) A glossy, clear, or translucent ice formed by the relatively slow freezing of large, supercooled water droplets.

c) A mix of rime and clear ice.

Answer 9

C) A mix of rime and clear ice.

Question 10

Mixed ice can pose a hazard because

a) It tends to form horns near the top and bottom of the airfoil’s leading edge, which greatly affects airflow.

b) It can spread over more of the airframe’s surface and is difficult to remove than rime ice.

c) Its jagged texture can disrupt an aircraft’s aerodynamic integrity.

Answer 10

B) It can spread over more of the airframe’s surface and is difficult to remove than rime ice.

Question 11

Structural icing is determined by many factors – the meteorological quantities most closely related to icing type and severity include

a) Supercooled liquid water content (SLWC).

b) Droplet size.

c) All are correct.

Answer 11

C) All are correct.

Question 12

Structural icing is determined by many factors – the meteorological quantities most closely related to icing type and severity include

a) Temperature (altitude).

b) Aircraft type/design and airspeed.

c) All are correct.

Answer 12

C) All are correct.

Question 13

Structural icing is determined by many factors – the meteorological quantities most closely related to icing type and severity include

a) Supercooled liquid water content (SLWC).

b) Aircraft type/design and airspeed

c) All are correct.

Answer 13

C) All are correct.

Question 14

For icing to occur, the outside air temperature must be

a) Below 0°C.

b) Below -10°C.

c) Below -40°C

Answer 14

A) Below 0°C.

Question 15

Most icing reports occur in the vicinity of

a) Marine environments.

b) Fronts.

c) Fog.

Answer 15

B) Fronts.

Question 16

A favored location for severe clear icing is

a) Freezing rain and/or freezing drizzle below a front.

b) Advection fog inland from a coastal area.

c) All of the above.

Answer 16

A) Freezing rain and/or freezing drizzle below a front.

Question 17

Structural icing

a) Degrades an aircraft’s performance as it destroys the smooth flow of air, increasing lift while decreasing the ability of the airfoil to create drag.

b) Increases an aircraft’s performance as it increased the size of the airfoil.

c) Degrades an aircraft’s performance as it destroys the smooth flow of air, increasing drag while decreasing the ability of the airfoil to create lift.

Answer 17

C) Degrades an aircraft’s performance as it destroys the smooth flow of air, increasing drag while decreasing the ability of the airfoil to create lift.

Question 18

Wind tunnel and flight tests have shown that frost, snow, and ice accumulations (on the leading edge or upper surface of an airplane wing) no thicker than __________ can reduce lift by 30% and increase drag up to 40%.

a) A piece of course sandpaper.

b) 1⁄2 inch thick.

c) 3⁄4 inch thick.

Answer 18

A) A piece of course sandpaper.

Question 19

Rotor blade icing is complex due to

a) The constant angle of attack experienced by the main rotor blades in normal forward flight.

b) The constantly changing angle of attack experienced by the main rotor blades in normal forward flight.

c) The constantly changing center of pressure experienced by the main rotor blades in normal forward flight.

Answer 19

B) The constantly changing angle of attack experienced by the main rotor blades in normal forward flight.

Question 20

The major operational hazard of helicopter main rotor blade icing is

a) The deterioration of normal autorotational qualities.

b) The increasing possibility of experiencing settling with power.

c) Over-torqueing due to the increased weight of the ice on the main rotor system.

Answer 20

A) The deterioration of normal autorotational qualities.

Question 21

A reported result from a U.S Army investigation on rotor blade icing indicates

a) That with about 1⁄2 inch of ice on the outer portion of the main rotor blades, rotor rpm overspeed may occur during autorotation due to the additional weight of the ice.

b) That with about 1⁄2 inch of ice on the outer portion of the main rotor blades, minimum rotor rpm cannot be maintained during autorotation.

c) That with about 1⁄2 inch of ice on the inner portion of the main rotor blades, minimum rotor rpm cannot be maintained during autorotation.

Answer 21

C) That with about 1⁄2 inch of ice on the inner portion of the main rotor blades, minimum rotor rpm cannot be maintained during autorotation.

Question 22

It is easy for a pilot to determine the amount of ice accumulation on the main rotor system during flight.

a) True.

b) False.

Answer 22

B) False.

Question 23

Asymmetrical shedding of main rotor blade ice inflight can

a) Be beneficial by restoring the rotor blades to a more efficient or clean configuration, and by reducing the weight of the aircraft.

b) Create severe vibrations depending on the amount of ice discharged.

c) All are correct.

Answer 23

B) Create severe vibrations depending on the amount of ice discharged.

Question 24

Ice shedding from the main or tail rotor systems in flight may cause damage to

a) The engine.

b) The airframe.

c) All are correct.

Answer 24

C) All are correct.

Question 25

Inflight icing presents a hazard to normal engine performance due to

a) Ice ingestion.

b) Air starvation.

c) All are correct.

Answer 25

C) All are correct.

Question 26

Engine ice ingestion is minimized on many helicopters by the availability of __________ used to prevent the accumulation of ice deposits in the area immediately forward of the compressor section.

a) Engine anti-ice.

b) Engine de-ice.

c) Engine ice preventative measures have not been certified on helicopters to date.

Answer 26

A) Engine anti-ice.

Question 27

Even when the engine air inlet anti-icing system is capable of sufficiently heating the engine inlet surfaces, there is still the threat of random ice ingestion if deposits on rotors, fuselage sections, antennas, or windshield surfaces shed ice and it is directed into the engine air intake stream.

a) True.

b) False.

Answer 27

A) True.

Question 28

Engine anti-icing systems will prevent the buildup of ingestible ice deposits only when outside meteorological conditions or aircraft operating conditions (most notable forward airspeed) do not exceed system design capabilities.

a) True.

b) False.

Answer 28

A) True.

Question 29

Engine anti-icing systems will prevent the buildup of ingestible ice deposits regardless of outside meteorological conditions or aircraft operating conditions (most notable forward airspeed).

a) True.

b) False.

Answer 29

B) False.

Question 30

The term “forecast icing conditions” is defined as

a) Environmental conditions expected by a National Weather Service or an FAA-approved weather provider to be conducive to the formation of inflight icing on aircraft.

b) Atmospheric conditions in which the formation of ice in observed or detected in flight.

c) Atmospheric icing conditions that are typically defined by airframe manufacturers relative to temperature and visible moisture that may result in aircraft ice accretion on the ground or in flight – typically defined in the RFM.

Answer 30

A) Environmental conditions expected by a National Weather Service or an FAA-approved weather provider to be conducive to the formation of inflight icing on aircraft.

Question 31

The term “known icing conditions” is defined as

a) Environmental conditions expected by a National Weather Service or an FAA-approved weather provider to be conducive to the formation of inflight icing on aircraft.

b) Atmospheric conditions in which the formation of ice is observed or detected in flight.

c) Atmospheric icing conditions that are typically defined by airframe manufacturers relative to temperature and visible moisture that may result in aircraft ice accretion on the ground or in flight – typically defined in the RFM.

Answer 31

B) Atmospheric conditions in which the formation of ice is observed or detected in flight.

Question 32

According to 14 CFR 135.227(d), may a pilot fly a helicopter under VFR into known icing conditions?

a) No.

b) Yes, if the aircraft has approved engine anti-icing installed and is operational.

Answer 32

A) No.

Question 33

According to the HAA General Operations Manual, what should a pilot do when encountering icing conditions?

a) The PIC should maneuver the aircraft so as to immediately remove the aircraft from icing, or land as soon as possible.

b) Land immediately.

c) Turn on engine anti-ice and pitot heat, continue flight while monitoring ice accretion on the windscreen.

Answer 33

A) The PIC should maneuver the aircraft so as to immediately remove the aircraft from icing, or land as soon as possible.