Test 3: Icing

Question 1

Is any aircraft certified for severe icing?

Answer 1

No

Question 2

What are the effects of ice on an aircraft?

Answer 2

Increased drag, increased weight, decreased lift, and decreased thrust/propeller efficiency

Question 3

How much can 1/2 in of ice reduce lift and increase drag?

Answer 3

It can increase by 60% and reduce lift by 50%

Question 4

About 90% of Icing Encounters are:

Answer 4

less than 50 miles long, not more than 3000 ft deep and occur between 0 and -20 degrees C (80% of the time an altitude change of 2000ft will take the aircraft out of serious icing

Question 5

Clear ICe

Answer 5

10% of all encounters
large droplets, freezing slowly
0 to -10 C
Dense, hard, heavy

Question 6

Rime Ice

Answer 6

70% of all encounters
small droplets, rapid freezing
-10 to -20 degrees C
relatively light and easily removed
stratiform clouds

Question 7

Mixed Ice

Answer 7

20% of encounters

Supercooled water and snow/ice coexist in the cloud

Question 8

Definition of known icing:

Answer 8

When pilots know or should know of icing weather forecasts (what would a reasonable prudent pilot do?)

Question 9

Are icing and turbulence microscale?

Answer 9

Yes, they are hard to forecast, use guilt by association instead

Question 10

What is the coldest liquid water is possible?

Answer 10

-40C

Question 11

Liquid water content in a cloud increases of decreases with age?

Answer 11

Increases

Question 12

Icing intensity is defined as amount of ice on a 3” diameter wing at 200 mph

Answer 12

It is a fixed diameter (DC-3)

Question 13

Trace

Answer 13

0.0-1.0 G/CM^2/HR
Ice is perceptible, accumulation is slightly greater than rate of sublimation, unless encountered for one hour or more, de-ice or anti-ice equipment or heading/altitude change is not required.

Question 14

Light

Answer 14

1.0-6.0 G/CM^2/HR
The rate of accumulation may create a problem if flight in this environment for one hour. De/anti-icing required occasionally to remove/prevent accumulatoin or heading and altitude chagne required.

Question 15

Moderate

Answer 15

6.0-12.0 G/CM^2/HR
The rate of accumulation is such that even short encounters become potentially hazardous. de/anti altitude and heading change required

Question 16

Severe

Answer 16

More than 12 G/CM^2/HR
The rate of accumulation is more than the de-ice / anti-ice equipment can get rid of, immediate heading or altitude change is required

Question 17

Physical factors affecting ice

Answer 17

-temperature
-liquid water content
-droplet size
collection efficiency

Question 18

Temperature

Answer 18

determine how likely the droplets will be already frozen and how quickly the supercooled droplets will freeze. Clear -10 to 0C / Rime -20 to -10 or stratiform (+5 to -20C)

Question 19

Icing Risk Temp

Answer 19

stratiform high = 0 to -15, medium -15 to -30, low

Question 20

Droplet Size

Answer 20

small = ice formation is limited to leading edges
medium = ice occurs aft of leading edge, but not aft of protected areas
large = extends aft of normally protected areas
freezing rain or drizzle = formation to maximum projection of aircraft components into airstream
Droplet size increases collection efficiency, greater number of smaller droplets in stratiform, smaller number of larger droplets in cu.

Question 21

collection efficiency

Answer 21

increases with an increase in speed, droplet size, and decrease in radius of curvature

Question 22

Fact

Answer 22

85% of icing is associated with fronts near the low center

Question 23

At what temperature can you damage the boot if used?

Answer 23

below -65C

Question 24

Is the shape or amount of ice accretion most degrading?

Answer 24

The shape