Hazardous Weather Flashcards
(155 cards)
1
Q
What is a Crosswind?
A
- Wind that is not parallel
- to a runway
- or flight path.
2
Q
What is a Gust?
A
- Sudden,
- short
- increase in wind speed.
3
Q
What is a Tailwind?
A
- more than 90 degrees
- to the longitudinal axis
- of the runway
- or aircraft.
4
Q
What is variable wind?
A
Frequent wind direction change.
5
Q
What is Wind Shift?
A
- A narrow zone
- along which there is an abrupt change
- of wind direction.
6
Q
What is Ceiling?
A
- lowest layer aloft reported as broken or overcast;
2. or the vertical visibility into an indefinite ceiling.
7
Q
What is Indefinite Ceiling?
A
upward ceiling is a surface-based obscuration, (ex fog)
8
Q
What is fog?
A
- minute water droplets
- reduce horizontal visibility to less than 5/8SM
- does not fall to the ground.
9
Q
What is precipitation?
A
Any form of water that falls to the ground.
10
Q
What is blowing snow?
A
- Snow lifted from the ground by wind
- 6’ up or more,
- reduces horizontal visibility to less than 7SM.
11
Q
What is Volcanic Ash?
A
- Fine particles of rock powder from a volcano
2. may remain airborne for long periods.
12
Q
What is Mountain Obscuration?
A
- when pilots can’t maintain visual contact with mountains or ridges
- due to clouds,
- precipitation, or
- obscurations.
13
Q
What is Aircraft Turbulence?
A
- Irregular motion of an aircraft in flight,
- normally rapid up and down motions,
- caused by a rapid variation of wind speed.
14
Q
What is Convective Turbulence?
A
- Turbulent vertical motions
- result from convective currents
- and the subsequent rising and sinking of air.
15
Q
What is Mechanical Turbulence?
A
Turbulence caused by obstructions, such as trees, buildings, terrain, etc.
16
Q
What is Mountain Wave?
A
- when stable air flow passes over a mountain or mountain ridge
- makes a disturbance
17
Q
What is wind shear?
A
- A change in wind speed and/or direction
- in a short distance
- resulting in a tearing or shearing effect.
18
Q
What is temperature inversion?
A
When temperature increases with altitude.
19
Q
What is CAT?
A
Clear Air Turbulence.
20
Q
What is Clear Air Turbulence?
A
- FL200 - FL500
- in cloud-free regions,
- associated with wind shear,
- can affect aircraft without warning.
21
Q
What is Rime Ice?
A
- Rough, milky, opaque ice
- formed by the instantaneous freezing
- of small super cooled water droplets.
22
Q
What is Clear Ice?
A
- glossy, translucent ice
- formed by slow freezing
- of large super cooled water droplets.
23
Q
What is a Thunderstorm?
A
- produced by cumulonimbus clouds,
- always accompanied by lightning and thunder
- usually with strong gusts of wind, heavy rain, and sometimes hail.
24
Q
What is a Downburst?
A
- strong downdraft
- creates damaging winds on or near the ground.
- Winds can be straight or curved
- Size, duration, and intensity varies.
- Can cause significant damage.
25
What types of winds are responsible for most weather-related accidents?
Adverse winds
26
What two phases of flight are the most vulnerable?
1. Takeoff
| 2. Landing
27
What aircraft are most affected by adverse winds?
Small aircraft.
28
Why are smaller aircraft most affected by adverse winds in the takeoff/landing phase of flight?
They tend to have slower airspeeds in those phases.
29
Can adverse winds affect air traffic decisions?
Yes
30
In what two main ways can adverse winds affect air traffic decisions?
1. Runway Changes
| 2. Slower arrival rates
31
What are the 4 types of adverse winds?
1. Crosswind
2. Tailwind
3. Gusts
4. Changing winds
32
In what direction, relative to the wind, do aircraft attempt to depart/land as much as possible?
Into the wind
33
Why do aircraft depart/land into the wind as much as possible? (2 reasons)
1. Groundspeed is slowed
| 2. More lift is generated
34
What 3 effects can a crosswind have on an aircraft?
1. Reduce aircraft performance.
2. Can blow aircraft off course
3. Can force aircraft to lean or drift on landing/takeoff
35
In what two ways can a crosswind force an aircraft to lean or drift on landing/takeoff?
1. Cause Loss of Control.
| 2. Cause Landing gear to collapse.
36
What effect can a tailwind have on an aircraft?
drastically reduce aircraft performance.
37
How can an aircraft compensate for a tailwind during takeoff/landing?
Operate a higher speeds at those times
38
If an aircraft needs to operate at higher speeds at takeoff and landing, how does a runway need to be changed to allow this?
Runway length needs to increase.
39
How can a tailwind reduce aircraft performance during takeoff?
Slower climbs
40
In what 3 ways can gusts disrupt an airflight?
1. Cause rapid changes in airspeed
2. Airspeed changes again when gust dissipates
3. Aircraft may maneuver unexpectedly.
41
If an aircraft speed rapidly changes (especially in response to a gust) what can that lead to?
Altitude change.
42
What are the 2 types of changing winds?
1. Variable wind
| 2. Sudden wind shift
43
What problem can variable wind cause aircraft?
Aircraft can have difficulty aligning/adjusting
44
Where can sudden wind shifts typically be found?
Leading edge of storms
45
What is the characteristic of wind direction in changing winds?
Wind direction can change dramatically and rapidly.
46
IMC?
Instrument Meteorological conditions
47
What is the greatest cause of fatal accidents?
Visual flight into IFR weather.
48
What is the most common cause of visual flight into IFR weather accidents?
Vertigo
49
What are the 5 hazards of IFR weather/conditions?
1. Fog
2. Precipitation
3. Volcanic Ash
4. Indefinite Ceiling
5. Mountain Obscuration
50
What is the primary hazard caused by Indefinite Ceiling?
Restricts slant range (air-to-ground) visibility.
51
What is the most common IFR weather hazard?
Fog
52
When does fog form?
When temp and dew point are the same
53
What is fog?
clouds that begin at the surface
54
Can fog form rapidly?
yes
55
What 3 forms of precipitation commonly produce IFR weather?
Rain
Drizzle
Snow
56
How low can heavy rain reduce visibility?
below 1 SM
57
How low can snow reduce visibility to?
zero
58
How much visibility is there in "whiteout" conditions?
zero
59
What type of snow is prone to being blown?
powdery
60
What can create whiteout conditions?
Blowing snow
61
What can ingesting volcanic ash provoke an engine to do?
Fail
62
What can volcanic ash on the ground cause?
Loss of traction
63
Is volcanic ash easy to see?
No.
64
In what circumstances is volcanic ash especially difficult to see?
1. Night
| 2. IFR weather
65
Is volcanic ash always seen by RADAR?
No
66
In terms of Mountain Obscuration, elevation variations can make surface weather reports __________.
Misleading
67
Regarding Mountain Obscuration, why can elevation variations make surface weather reports misleading?
Weather Stations are typically in valleys.
68
______ can hide mountainous terrain?
Clouds
69
What are the 3 main causes of turbulence?
1. Convective air currents
2. Obstructions to wind flow
3. Wind shear.
70
What type of turbulence is caused by convective currents?
Convective turbulence.
71
What type of turbulence is caused by Obstructions to wind flow?
mechanical turbulence
72
In what weather conditions is convective turbulence frequent?
1. Warm summer afternoons
| 2. Light winds
73
If moisture is present, what is convective turbulence indicated by?
Billowy cumuliform clouds.
74
Where does convective turbulence derive its strength?
Surface heating
75
What can cause convective turbulence to vary widely?
Uneven surface heat.
76
What are obstructions to wind flow?
Anything that disturbs smooth airflow.
77
What 2 factors does the intensity of mechanical turbulence depend on?
1. Wind speed
| 2. Shape of obstructions
78
What is one type of extreme mechanical turbulence regarding mountains?
Mountain wave
79
Where does mountain wave form?
Downwind side of a mountain
80
Can mountain wave produce extreme turbulence?
Yes
81
What causes mountain wave?
Mountains remain stationary while winds blow rapidly through them
82
Can mountain waves extend vertically to high altitudes?
Yes
83
What 3 types of cloud formations can indicate mountain wave.
1. Cap
2. Rotor
3. Alto/Cirro cumulus standing lenticular.
84
At what altitude can wind shear occur?
Any
85
What causes wind shear?
Temperature Inversions
86
Where can temperature inversions cause wind shear?
Where warm and cold air meet
87
What are the 3 most common locations/circumstances for wind shears to occur?
1. Low to the ground
2. Along storm fronts
3. In a valley
88
Why do wind shears occur so often low to the ground?
Ground cools at night
89
Why do wind shears occur so often in valleys?
Cold air gets trapped in a valley.
90
When are CATs most frequent and intense?
During winter
91
How can CATs be avoided by aircraft?
Change altitude.
92
What is the code for light turbulence?
LGT
93
What is the aircraft reaction to light turbulence?
Slight, erratic changes to altitude, pitch, roll, and yaw.
94
What is the reaction inside the aircraft to light turbulence?
1. slight strain against seat belts
2. Unsecured objects may be slightly displaced
3. little or no difficulty walking
95
What is the code for moderate turbulence?
MOD
96
What is the aircraft reaction to moderate turbulence?
1. Changes in altitude and/or attitude
2. Changes in indicated airspeed
3. aircraft remains in positive control
97
What is the attitude of the aircraft?
The direction it is turning (pitch, roll, or yaw)
98
What is the reaction inside the aircraft to moderate turbulence?
1. definite strains against seat belts
2. Unsecured objects are dislodged
3. walking is difficult
99
What is the code for severe turbulence?
SEV
100
What is the aircraft reaction to severe turbulence?
1. large, abrupt changes in altitude and/or attitude
2. large variations in indicated airspeed
3. Aircraft may be momentarily out of control
101
What is the reaction inside the aircraft to severe turbulence?
1. Occupants are forced violently against seat belts
2. Unsecured objects are tossed about
3. walking is impossible
102
What is the code for extreme turbulence?
EXTRM
103
What is the aircraft reaction to extreme turbulence?
1. Aircraft impossible to control
| 2. Structural damage possible
104
What are the 4 categories of turbulence?
1. Light
2. Moderate
3. Severe
4. Extreme
105
What is "Chop"?
1. turbulence which causes rapid bumpiness
| 2. No change in altitude or attitude.
106
What are the 2 classifications of chop?
1. Light
| 2. Moderate
107
What are the 5 factors that can affect aircraft turbulence?
1. Aircraft size
2. Altitude
3. Airspeed
4. Wing loading
5. Intensity
108
What is the formula for wing loading?
aircraft weight (in pounds)/wing area (in square feet)
109
In what 2 types of clouds does super cooled water often exist?
1. Stratiform
| 2. Cumulus
110
What are the 3 types of ice an aircraft may encounter?
1. Rime
2. Clear
3. Mixed
111
What is the most common type of ice an aircraft may encounter?
Rime
112
What is the least serious type of ice an aircraft may encounter?
Rime
113
Is Rime Ice easy to remove?
yes
114
Is Rime controllable with anti-icing equipment
yes
115
What does Rime ice on the aircraft do to the smooth flow of air
Disturbs the smooth flow of air
116
What are 2 favorable conditions for Rime ice?
1. Small droplets
| 2. Lower liquid water content in cloud
117
What are 4 aspects of clear ice that make it worse for aircraft than Rime ice?
1. difficult to see
2. difficult to remove
3. May not be controllable with anti-icing equipment
4. Greatly disturbs airflow
118
What are the 2 favorable conditions for clear ice?
1. Large droplets
| 2. Higher liquid water content in the cloud
119
What is mixed icing?
1. Layers of both rime and clear
| 2. combines the effects of both
120
What are the 4 intensity levels of icing?
1. Trace
2. Light
3. Moderate
4. Severe
121
At what level of icing is anti-icing equipment not utilized unless the ice is encountered for over an hour?
Trace
122
At what 2 levels of icing does the ice not present a problem if anti-icing equipment is used?
1. Trace
| 2. Light
123
At what level of icing is immediate flight diversion necessary?
Severe
124
What 4 factors affect icing?
1. Aircraft type
2. Altitude
3. Airspeed
4. Meteorological conditions
125
What type of aircraft is less susceptible to icing?
Commercial aircraft
126
What are the 2 reasons why commercial aircraft are usually less susceptible to icing?
1. Strong anti-icing equipment
| 2. Tend to operate at altitudes too cold for icing.
127
What effect does altitude have on icing?
Lower altitudes are usually more conducive to icing.
128
What 3 meteorological conditions can affect icing?
1. Temperature
2. Moisture content
3. Droplet Size.
129
What 5 effects may icing have on aircraft?
1. increase drag
2. increase weight
3. decrease lift
4. Block airflow to pilot tubes
5. Light aircraft may lose control.
130
What is the least significant effect icing can have on an aircraft?
increase weight
131
What is the most significant effect icing can have on an aircraft?
decrease lift
132
What effect can ice blocking airflow to pilot tubes have?
Causes incorrect speed/altitude headings
133
What are 8 types of hazards thunderstorms can contain?
1. Hail
2. Icing
3. winds
4. Tornadoes
5. Turbulence
6. IFR conditions
7. Microbursts/downbursts
8. Rapid pressure changes
134
Should pilots avoid storms
yes
135
What 3 things do thunderstorms need to form?
1. Water Vapor
2. Unstable air
3. Converging winds near surface or fronts
136
What are the 3 stages of a thunderstorm?
1. Towering cumulus
2. Mature
3. Dissipating
137
How powerful to the updrafts have to be in the towering cumulus stage to form a thunderstorm?
Greater than 3,000 ft./min
138
What is the most hazardous stage of a thunderstorm?
Mature
139
In the mature stage of a thunderstorm, what is the leading edge of the downdraft called?
Gust front
140
In what stage of a thunderstorm does the precipitation reach the surface?
Mature
141
What 2 things occur in the dissipating stage of a thunderstorm?
1. Precipitation ends
| 2. Cloud vaporizes from below
142
What are the 3 types of low level wind shear and downburst?
1. Microburst
2. Macroburst
3. Low Level Wind Shear
143
What are the 3 characteristics of a microburst?
1. Up to 2.5 miles wide
2. Lasts 2-5 mins
3. Peak winds: 150 kts
144
What are the 3 characteristics of a macroburst?
1. 2.5 - 10 miles wide
2. Lasts 5-30 minutes
3. Peak winds: 120 kts
145
What are the 3 characteristics of a low level wind shear?
1. 10 kts or more per 100'
2. in a layer more than 200' thick
3. within 2000' of the surface
146
What are the 3 wind shear/downburst warning systems
1. LLWAS
2. TDWR
3. WSP
147
LLWAS?
Low Level Wind Shear Alert System
148
Low Level Wind Shear Alert System?
1. Detects wind shear at the surface
| 2. Installed around airports
149
TDWR
Terminal Doppler Weather Radar
150
Terminal Doppler Weather Radar?
1. Weather radar
| 2. Detects microbursts, gust fronts, convective storms.
151
WSP
Weather system processor
152
Weather system processor?
1. Enhanced system for airport surveillance radar (ASR)
| 2. Detects low level wind shear.
153
ASR?
Airport surveillance radar
154
What are the 2 effects of windshear?
1. rapid gain/loss of airspeed
| 2. aircraft can go above/below glideslope unexpectedly.
155
What are the 2 effects of downbursts during landing/takeoff
1. Rapid loss of lift
| 2. Can be impossible to recover from
