AVIATION EXAM 3 steph

Frost formation on an aircraft sitting on the ramp at night requires:

- Clear skies -Light surface winds (or calm) - Surface temperature at or below 0o C.

With respect to aircraft icing, temperature:

- Determines how likely the hydrometeors are to be already frozen - Determines how quickly the hydrometeors will freeze

Evidence that the airplane is flying in SLD conditions includes:

- Ice forming aft of the active part of the deicer boots -Ice forming further aft than normal on the propeller spinner - Granular ice crystals or ice rivulets running back on the cockpit side windows

One problem with icing is that there are a nearly limitless variety of ice shapes, thicknesses, and textures. The effects of each of these shapes is to change the airfoil:

- lift - drag - stall angle

Temperature of rime and texture

-10 to -20 C relatively light and easily removed stratiform clouds

One of the factors that may further exacerbate the onset of tail stall due to icing, in aircraft that are susceptible to that phenomenon is:

-A negative g pushover at flap actuation -Flying landing approaches at higher than normal reference speed

Potential icing zones depend on:

-Altitude and temperature - Cloud type - Synoptic situation and season

Supercooled large droplets (SLD) include:

-Freezing rain - Freezing drizzle - SCDD

Holdover times for all types of ground deicing fluids are decreased by:

-Heavy precipitation rates. - High moisture content. - High wind velocity or jet blast.

Accurate icing forecasts are difficult because:

-Icing is a microscale phenomenon - Icing is aircraft specific - Normal data resolution does not allow for measurement of the icing environment

You are flying an airplane that is certified for flight in known icing. You begin to encounter severe icing at 10,000 ft MSL. This operation:

-Is not approved for your aircraft -Should be reported to ATC

Indication(s) that tail stall is occurring is/are:

-Rapid forward movement of the control yoke - Heavy stick forces - Rapid lowering of the pitch attitude

One of the most hazardous icing situations occurs when aircraft encounter supercooled drizzle drops (SCDD). The conditions associated with SCDD include:

-Temperatures below 0C - Droplet diameters of 40 to 400 microns

MU values are provided at many airports to provide flight crews with information on runway surface friction conditions. MU values range between:

0 and 100

Temperature of clear ice and texture and cloud type

0 to -10C dense, hard, heavy cumulus

ice accumulation rate of trace ice

0.0-1.0 g/cm^2/hr

With respect to temperature, icing is most likely in the range:

0oC and -20 oC

More than ___ of all icing accidents occur in the landing phase

2/3

80% of the time an altitude change of _____ will take aircraft out of serious icing

2000Ft

According to NASA data, about 90% of icing encounters are:

3000 ft or less in thickness

1/2 in. of can reduce lift by ____ and increase drag by____

50%, 60% or more

ice accumulation rate of moderate ice

6.0 - 12.0 G/CM2/HR

ice accumulation rate of severe ice

>12 g/cm2/hr

Current icing intensity accumulation rates are defined with respect to:

A circular cylinder of defined diameter

Type I deicing fluids are:

A mixture of water and ethylene glycol

With respect to icing associated with fronts, which of the following has the potential of producing the most severe icing encounter?

A warm front

With respect to utilizing deicing boots, a good operating practice is to:

Actuate the boots when the ice has become visible on the boot

Tailplane icing is most likely to manifest itself as:

An abrupt pitch-down with flap extension

What is a primary difference between "deicing equipment", and "anti-icing equipment", in terms of its use?

Anti-icing equipment should be turned on prior to encountering ice

The type of ice that occurs with slow freezing of large droplets is:

Clear

Type of ice that is 10% of encounters Large droplets, freezing slowly

Clear ice

If you are encountering freezing precipitation, you are most likely in which sector of the approaching extratropical cyclone?

Cool

Large radius of curvature of aircraft structures:

Decreases collection efficiency

The presence of small supercooled droplets:

Decreases collection efficiency

With respect to autopilot use in icing conditions, you should:

Disconnect the autopilot and hand-fly the airplane

A "supercooled droplet" is one that:

Exists in liquid form at temperatures below 0C

Cloud droplet size is a factor related to the collection efficiency of an aircraft in an icing situation. The presence of super-cooled precipitation-sized droplets will most likely result in:

Ice formation to maximum projection of aircraft components into the airstream

One of the most insidious effects of ice on an aircraft is that:

Ice shape on the airfoil can take a number of forms, each causing potential changes in airfoil characteristics

icing effects

Increased Drag Increased Weight Decreased Lift Decreased Thrust/ Propeller Efficiency

Rate of accretion/ icing intensity increases with

LWC

Liquid water content (LWC) is an important factor in aircraft icing events. With respect to liquid water content in clouds, you know that:

LWC tends to increase with altitude in cumulus clouds, to a maximum value, then decrease above that level

About 90% of Icing Encounters are: (3 things)

Less than 50 miles long Not more than 3000 ft deep Occur in clouds between 0 and -20 degrees C.

Tailplane icing is (for a given icing encounter):

More likely than wing icing

In order to use any type of ground deicing fluid, the PIC should consult:

The Pilot's Operating Manual for the aircraft

If you see the following on a TAF, what does it mean: "Runway 28 Mu 38, 43, 24"?

The friction levels on Runway 28 are 38%, 43%, and 24%, respectively, for the first 1/3, the middle 1/3, and the last 1/3 of the runway

Dynamic hydroplaning occurs when standing water on the runway prevents the tires of the aircraft from making full contact with the runway surface. Dynamic hydroplaning is proportional to:

The square root of the tire pressure

in which aircraft does the tailplane generally collects ice more effectively than does the wing

Turboprop aircraft

Collection Efficiency dependent on

drop size, aircraft speed and radius of curvature

Max. droplet size in

freezing precip

Ice formation to maximum projection of aircraft components into airstream.

freezing rain and drizzle

Deicing/anti-icing systems

hot air systems electrical resistance systems liquid systems expandable boot systems

Most icing accidents occur during:

landing

Localized topography is important such as

large bodies of water (great lakes) and orography

Ice formation extends aft of normally protected surfaces

large drops

A MU value of 25 means that runway surface friction is ________ than that for a MU value of 40.

less

In general, Type IV deicing fluids allow _______holdover times than Type I deicing fluids.

longer

Ice occurs aft of leading edge, but does not extend aft of protected area

medium drops

Icing is a

microscale phenomenon

20% of encounters Supercooled water and snow/ice coexist in the cloud

mixed ice

If you are flying in an icing condition in which a short encounter is becoming hazardous and you must utilize deicing/anti-icing equipment or divert the aircraft, you are encountering:

moderate icing

A given thickness of ice on the tail will generally have a _____ ______ aerodynamic effect than the same thickness of ice on the wing

more adverse

Relative to icing intensity in non-mountainous regions, icing in the near-vicinity of high terrain tends to be:

more intense

With respect to synoptic situation, most icing encounters occur:

near frontal zones

The type of ice that is most often encountered by aircraft in flight is:

rime

The type of ice that occurs with rapid freezing of supercooled droplets is:

rime

The ____ of ice accretion is more critical than ice thickness in degrading the aerodynamic lift of the tail

shape

Ice formation is limited to leading edges.

small drops

This collection efficiency increases as

speed and droplet size decrease

Greater number of smaller droplets in

stratus

what determines how likely the droplets will be already frozen and how quickly the supercooled droplets will freeze

temperature

which aircraft is exposed to icing conditions for a greater percentage of flight time than are aircraft flying longer routes

turboprops

Which of the following is a type of deicing (only) equipment?

boots

Higher LWC with lower cloud base and higher

cloud base temp

______icing conditions occur infrequently

critical

LWS inc with height in what cloud?

cumulus

Smaller number of larger droplets in

cumulus

Icing intensity forecasts represent the most probable maximum conditions based upon

current meteorological conditions

ice accumulation rate of light ice

1.0 - 6.0 G/CM2/HR

On some airfoils, ___ inch of critical ice shape may cause unacceptable aerodynamic penalties

1/2

More than ____ of landing accidents involving ice are fatal

1/3

______% of all weather accidents result from icing

10.8%

1/8 in. can increase stall speed by

16-20%

As cloud liquid water content increases:

Rate of ice accretion increases

If you encounter an uncommanded roll while in SLD icing conditions, you should

Reduce angle of attack

type of ice that is 70% of encounters Small droplets, rapid freezing

Rime ice

LWC tends to be smaller and more uniform in

Stratus

Orographic Influences are

Strong Vertical Motion Adiabatic Cooling High Density Altitude Effects

Icing certification is based upon statistical probabilities, requiring that (with maximum icing conditions) the aircraft be able to:

Successfully negotiate an icing encounter of 2.6 miles through a wide range of altitudes in cumulus clouds (maximum intermittent icing), and Successfully negotiate an icing encounter of 17.4 miles in stratiform clouds (maximum continuous icing).

Physical Factors Affecting Icing

Temperature Liquid Water Content Droplet Size Collection Efficiency