Lesson 23 Flashcards
(88 cards)
1
Q
Per 7110.65, controllers shall advise pilots of hazardous weather that may impact operations within ______ of their sector or area.
A
150 NM
2
Q
Name the Factors that Influence Aviation Weather Safety: (3)
A
- pilot ratings and experience
- aircraft design and performance specifications
- onboard equipment
3
Q
______ is responsible for most weather related accidents
A
adverse wind
4
Q
_________ are most susceptible to adverse wind.
A
takeoff and landing
5
Q
Crosswind
A
wind that is not parallel to the runway or path of an aircraft
6
Q
What happens when aircraft are oriented into the wind for take off and landing?
A
- more efficient
- groundspeed is minimized
- less runway is required to achieve lift off
- pilot has more time to make adjustments necessary for a smooth landing
7
Q
What happens when aircraft are oriented into the wind for take off and landing?
A
- more efficient
- groundspeed is minimized
- less runway is required to achieve lift off
- pilot has more time to make adjustments necessary for a smooth landing
8
Q
What happens if a pilot does not correctly compensate for the crosswind?
A
- aircraft may drift off the side of the runway
- side load on the landing gear might occur, leading to gear collapse
9
Q
Gust
A
a sudden, brief increase in the speed of the wind
10
Q
What is the main issue gusts cause?
A
airspeed fluctuations
11
Q
Tailwind
A
any wind more than 90 degrees to the longitudinal axis of the runway
12
Q
A tailwind can be hazardous during both takeoff and landing because….
A
- a longer takeoff roll is required
- a higher ground speed is required
- a smaller initial rate of climb occurs during takeoff
- a longer landing roll is required
13
Q
Variable Wind
A
during the 2 minute evaluation period, it fluctuates by 60 degrees or more and the wind speed is more than 6 knots (larger shift at slower speed)
14
Q
Wind Shift
A
a change in wind direction of 45 degrees or more which takes place in less than 15 minutes and has sustained winds of 10 knots or more throughout the wind shift
15
Q
Why are variable winds and sudden wind shifts dangerous?
A
a headwind can quickly become a crosswind or tailwind
16
Q
Why are variable winds and sudden wind shifts dangerous?
A
a headwind can quickly become a crosswind or tailwind
17
Q
____ airplanes are more affected by tailwinds and crosswinds during takeoff and landing than _____ airplanes.
A
Small; Large
18
Q
Which type of aircraft will perform better in adverse wind conditions, due to its higher takeoff and approach speeds?
A
larger airplanes
19
Q
What is the single greatest cause of fatal accidents in relation to vertigo?
A
continued visual flight into IFR weather
20
Q
Ceiling
A
the lowest layer aloft reported as broken or overcast; or the vertical visibility into an indefinite ceiling
21
Q
Indefinite Ceiling
A
the ceiling classification that is applied when the reported ceiling value represents the vertical visibility upward into a surface based obscuration
22
Q
An ________ restricts the pilot’s slant range visibility, thus he may not see the runway ahead after he descends below the indefinite ceiling.
A
indefinite ceiling
23
Q
Which is more hazardous, an indefinite ceiling or an equal ceiling?
A
indefinite ceiling
24
Q
Fog
A
a visible aggregate of minute water droplets based at the Earth’s surface and reducing horizontal visibility to less than 5/8 SM; does not fall to the ground
25
When does fog form?
when the temperature and dew point of the air become identical (or nearly so)
26
When does fog form?
when the temperature and dew point of the air become identical (or nearly so)
27
Blowing Snow
snow lifted from the surface or the earth by the wind to a height of 6 ft or more above the ground and blow about in such quantities that the reported horizontal visibility is reduced to less than 7 SM
28
What causes a "whiteout"?
blowing snow
29
Volcanic Ash
fine particles of rock powder that originate from a volcano and that may remain suspended in the atmosphere for long periods
30
Mountain Obscuration
weather phenomena causing the obscuration of mountain peaks caused by clouds, precipitation, smoke, haze, mist or fog
31
Which precipitation types most commonly produce instrument weather?
rain, drizzle, and snow
32
Aircraft turbulence
irregular motion of an aircraft in flight, especially when characterized by rapid up and down motion, caused by a rapid variation of atmospheric wind velocities
33
Turbulence is caused by: (3)
- convective currents (called " convective turbulence"
- obstructions to wind flow (called "mechanical turbulence")
- wind shear
34
Turbulence is caused by: (3)
- convective currents (called " convective turbulence"
- obstructions to wind flow (called "mechanical turbulence")
- wind shear
35
Convective Currents are most active on ___________ when winds are light.
warm summer afternoons
36
What cloud type indicates convective turbulence?
billowy cumuliform clouds
37
Mechanical Turbulence occurs when.....
obstructions to the wind flow disrupt the smooth flow of air
38
Mechanical Turbulence intensity is directly related to:
- wind speed
| - roughness of the obstructions
39
Mountain Wave
an atmospheric wave disturbance formed when stable air flow passes over a mountain or mountain range
40
Characteristics of Mountain Waves:
- develop above and downwind of mountains
- may extend 100 miles or more downwind
- produces severe to extreme turbulence
- waves remain nearly stationary while the wind blows rapidly through them
41
Name the 3 conditions of a Wind Shear that are of special interest:
- wind shear with low-level temperature inversion
- wind shear with a frontal zone
- Clear Air Turbulence associated with the jet stream
42
Temperature Inversion
temperature increases with altitude
- - Inversions Occur:
- within the lowest few thousand feet above ground due to nighttime cooling
- along frontal zones
- when cold air is trapped in a valley
43
Temperature Inversion
temperature increases with altitude
- - Inversions Occur:
- within the lowest few thousand feet above ground due to nighttime cooling
- along frontal zones
- when cold air is trapped in a valley
44
Clear Air Turbulence (CAT)
a higher altitude (20,000 to 50,000 ft) turbulence phenomenon occurring in cloud free regions, associated with wind shear, particularly between the core of a jet stream and the surrounding air
45
When is CAT frequency and intensity maximized?
during winter when the jet streams are the strongest
46
When is CAT frequency and intensity maximized?
during winter when the jet streams are the strongest
47
Name the 4 intensities of Turbulence:
- Light (LGT)
- Moderate (MOD)
- Severe (SEV)
- Extreme (EXTRM)
48
Light (LGT) Turbulence
- momentarily causes slight erratic changes in altitude and/or attitude (pitch, roll, yaw)
- occupants may feel a slight strain against seat belts or shoulder straps. unsecured objects may be displaced slightly.
49
Moderate (MOD) Turbulence
- changes in altitude and/or attitude occur but the aircraft remains in positive control at all times; variations in indicated airspeed
- occupants feel definite strains against seat belts or shoulder straps; unsecured objects are dislodged
50
Severe (SEV) Turbulence
- large abrupt changes in altitude and/or attitude; causes large variations in indicated airspeed; a/c may be momentarily out of control
- occupants forced violently against seatbelts or shoulder straps; unsecured objects are tossed about
51
Extreme (EXTRM) Turbulence
a/c violently tossed about and is practically impossible to control; may cause structural damage
52
Extreme (EXTRM) Turbulence
a/c violently tossed about and is practically impossible to control; may cause structural damages
53
When the air is too dry for cumuliform clouds to form, ______ currents caused by uneven surface heating can still be active and cause turbulence.
convective
54
High Density Altitude
a condition of the atmosphere that reduces an aircrafts performance capability below a level of standard performance at a specified altitude
55
_____ is ice that sticks to the outside of an a/c; forms when supercooled water strikes the aircraft's airframe; can accumulate on every exposed frontal surface of the airplane.
Structural Icing
56
Name the 3 types of structural icing:
- Rime
- Clear (or glaze)
- Mixed
57
Rime Ice
rough, milky, opaque ice formed by the instantaneous freezing of small supercooled water droplets after they strike the aircraft
58
Characteristics of Rime Ice
- most common
- least serious type of icing
- typically controlled by de icers/anti icers
- its shape and texture disturb the airflow
- its brittleness makes it easier to remove
59
Clear Ice (or glaze ice)
a glossy, clear or translucent ice formed by the relatively slow freezing of large supercooled water droplets
60
Characteristics of Clear Ice
- more hazardous than rime
- can greatly disrupt airflow
- pilot may not see it
- difficult to remove
- can spread beyond the reach of de icing / anti icing equipment
61
Characteristics of Clear Ice
- more hazardous than rime
- can greatly disrupt airflow
- pilot may not see it
- difficult to remove
- can spread beyond the reach of de icing / anti icing equipment
62
Mixed Ice
mixture of clear ice and rime ice; combines the dangerous effects of both clear and rime icing conditions
63
Name the 4 icing intensity classifications:
- Trace (TRACE)
- Light (LGT)
- Moderate (MOD)
- Severe (SEV)
64
Trace (TRACE)
- ice becomes perceptible
- rate of accumulation slightly greater than sublimation
- de icing/anti icing equipment is not utilized unless encountered for an extended period of time (over 1 hour)
65
Light (LGT)
- rate of accumulation may create a problem if flight is prolonged in the environment (over 1 hour)
- occasional use of deicing/ anti icing equipment removes/prevents accumulation
- does not present a problem if the deicing/ anti icing equipment is used
66
Moderate (MOD)
- rate of accumulation is such that even short encounters become potentially hazardous
- use of deicing/anti icing equipment or flight diversion is necessary
67
Severe (SEV)
- rate of accumulation is such that deicing/anti icing equipment fails to reduce or control the hazard
- immediate flight diversion is necessary
68
Severe (SEV)
- rate of accumulation is such that deicing/anti icing equipment fails to reduce or control the hazard
- immediate flight diversion is necessary
69
Supercooled Water
liquid water at temperatures below the freezing point
- will crystallize in the presence of a solid around which a crystal structure can form
- often exist in stratiform and cumulus clouds
70
Icing is dependent upon:
- aircraft type and design
- altitiude
- airspeed
- meteorological factors
71
What aircraft type is more susceptible to icing? and why?
Light Turboprops; because they fly at lower altitudes that support icing (0 to -20 degrees Celsius)
72
How do pilots avoid/escape from icing?
- exit the area of visible moisture
- climb or descend to positive temperatures
- climb to altitudes where temperatures are too cold to support supercooled droplets
73
High density altitude _____ an aircraft's power and thrust.
reduces
74
Aircraft icing potential is NOT dependent upon _____.
pilot rating
75
Which adverse effect of structural icing is LEAST significant to an aircraft?
increased weight
76
Which adverse effect of structural icing is LEAST significant to an aircraft?
increased weight
77
Thunderstorm
a storm produced by a cumulonimbus cloud and always accompanied by lightning and thunder, usually with strong gusts of wind, heavy rain and sometimes hail
78
Thunderstorm Cell Formation requires what 3 ingredients?
- water vapor
- unstable air
- lift
79
Name and Describe the 3 Stages of a Thunderstorm Cell:
1. Towering Cumulus Stage: updraft speeds of greater than 3,000 feet per minute
2. Mature Stage: downdraft reaches the surface; weather hazards reach peak intensity
3. Dissipating Stage: precipitation tapers off and ends; cloud gradually vaporizes from below leaving a remnant anvil cloud
80
Downburst
a strong downdraft which induces an outburst of damaging winds on or near the ground.
81
Microburst
a downburst that covers an area up to 2.5 miles along a side with peak winds as high as 150 knots that lasts 2-5 minutes
82
Macroburst
a downburst that covers an area greater than 2.5 miles up to 10 miles along a side with peak winds as high as 120 knots that last 5-30 minutes
83
Macroburst
a downburst that covers an area greater than 2.5 miles up to 10 miles along a side with peak winds as high as 120 knots that last 5-30 minutes
84
Thunderstorm cell formation requires _____, unstable air, and lift.
water vapor
85
Low level wind shear (LLWS)
a wind shear of 10 knots or more per 100 ft in a layer more than 200 ft thick which occurs within 2,000 ft of the surface (dangerous especially during takeoff and landing)
86
While an a/c is on approach, a shear from a headwind to a tailwind causes:
- airspeed to decrease
- nose to pitch down
- aircraft to drop below the glideslope
87
While an a/c is on approach, if the wind is calm, or there is a slight tailwind, and the flow shears into a headwind, this causes:
- airspeed to increase
- nose to pitch up
- aircraft to rise upward above the glideslope
- airplane will land long and could run out of runway
88
What type of aircraft are more prone to LLWS?
small, general aviation aircraft; because their approach speeds are much closer to their stall speeds
