JX Weather (CBT) Flashcards
(209 cards)
1
Q
Change of 1.0 inHg changes the altimeter by how many feet
A
1,000 feet
2
Q
You change your altimeter setting from 29.92 to 29.64. What will your altimeter indicate?
A
An decrease in altitude
3
Q
You change your altimeter setting from 29.92 to 30.60. What will your altimeter indicate?
A
A increase in altitude
4
Q
For every 11 deg C, how much of an altimeter error could you expect?
A
4%
5
Q
With standard pressure (29.92), what will your altimeter indicate if OAT is lower than standard?
A
It will read an altitude higher than you actually are
6
Q
With standard pressure (29.92), what will your altimeter indicate if OAT is higher than standard?
A
It will read an altitude lower than you actually are
7
Q
Define indicated altitude
A
Altitude as it is displayed on your altimeter
8
Q
Define absolute altitude
A
The acft’s altitude above the ground (AGL)
9
Q
Define true altitude
A
The acft’s altitude references to sea level (MSL)
10
Q
Define pressure altitude
A
Altitude above the standard datum plane (29.92 inHg)
11
Q
Define density altitude
A
Pressure altitude corrected for nonstandard temperature deviations. (Not a reference altitude, but rather indication of acft performance)
12
Q
Pure dry air contains what gasses and how much water vapor
A
Roughly:
78% nitrogen
21% oxygen
1% Other (10 gasses)
The atmosphere contains about 0-5% water vapor by volume
13
Q
Troposphere dimensions
A
Average of 55,000 feet at the equator to 28,000 at the poles
Hight above the U.S. is about 36,000
14
Q
Significance of the troposphere
A
Nearly all weather occurs in this layer
15
Q
Define lapse rate
A
temp decrease with an increase of altitude
16
Q
Define tropopause
A
- An abrupt change in temperature decrease with an increase of altitude
- Transition layer between the troposphere and the stratosphere
- Average hight of 36,000 over the U.S.
17
Q
Where do the strongest winds occur
A
Just bellow the tropopause
18
Q
Tropopause characteristics
A
- Strong winds
- Mod-sev turbulence
- Haze layer is common
- Temp is constant with altitude
- Normally the coldest area in the lower atmosphere
- Contrails occur… #Chemtrails
19
Q
Stratosphere
A
Above the tropopause
20
Q
Stratosphere characteristics
A
- increasing temperature as altitude increases (inversion) to approx 66,0000
- smooth air
- excellent visibility
21
Q
What is an ELR
A
- Existing lapse rate
- Gives meteorologist the type of weather that exists
22
Q
3 types of ELRs
A
- Standard
- Isothermal
- Inverted
23
Q
What is the standard lapse rate (temp)
A
2 deg C (or 3.5 F) per 1,000 feet
24
Q
What is Isothermal lapse rate
A
temp is constant with an increase in alt
25
What is inverted lapse rate
temp increases with an increase in alt (temp inversion)
26
Characteristics of an inverted lapse rate
- Few hundred - few thousand feet thick
- stable air
27
Average weight of air per square inch at sea level (standard conditions)
14.7 lbs
28
What is the relationship with altitude and pressure
- Always decreases with altitude
- pressure decreases more rapidly in the lower layers of the atmosphere (b/c air density)
29
What is inHg
measure of the high of a column of mercury that can be supported by atmospheric pressure
30
What is mb
The millibar is a direct measure of pressure defined by force per unit area
31
Standard day at sea level
- 29.92 inHg & 15 deg C (59 F)
or 1013.2 mb
32
What is the standard lapse rate (pressure)
1 inHg (or 34 mb) per 1,000 feet
33
What is station pressure
atmospheric pressure measured directly at an airfield or weather station
34
What do surface analysis charts show
- high and low pressure systems
- isobars
- ridges (high pressure/good wx)
- trough (low pressure/bad wx)
35
What are isobars
- Lines of equal (sea level) pressures
- depict horizontal distribution of pressure
36
Winds on charts will depict wind in relation to
True north
37
Winds reported from ATIS, tower, or RSU are in relation to
Magnetic north
38
What are the 3 station model wind indicators
- half barb = 5 kts
- barb = 10 kts
- penant = 50 kts
39
What weather conditions do a station model depict?
- Wind direction
- Wind speed
- sky cover (circle)
- temperature (top left)
- dew point (bottom left)
- sea level pressure (top right)
- pressure change (bottom right) +/- in last 3 hrs
40
How far apart are isobars spaced?
4 millibars apart
41
Wind characteristics in surface charts
- generally move in the same direction between pressure systems
- most cases, almost parallel to isobars
- High pressure system = clockwise
- Low pressure system = counterclockwise
42
Define pressure gradient
rate of change in a direction perpendicular to isobars
43
What is PGF
pressure gradient force
44
How is PGF represented
isobar spacing
45
Atmospheric circulation moves air by
mean of ascending and descending currents
46
descending air generates what pressure system
high pressure system
47
air moving upward generates what pressure system
low pressure system
48
Air spreads out, produces horizontal flow
high pressure system
49
air tries to converge toward the center
low pressure system
50
Coriolis force
- force created by earths rotation
- diverts wind to the right with respect to its initial direction (regardless of pressure system)
51
gradient winds
- combined force between the pressure gradient force and the Coriolis force
- flow perpendicular to pressure gradient force (parallel to isobars)
- results in northern hemisphere circulation (counterclockwise = low pressure system
clockwise = high pressure systems)
52
where are gradient winds found
above 2,000 ft AGL
53
When the PGF, Coriolis, and friction force balance (bellow 2,000ft AGL)
wind flows at a 45 deg across isobars from high to low pressure
54
wind speeds ______ with height through the troposphere; reach a maximum near the ______
increase; tropopause
55
Jet stream
- 50 knots or more (100-150; excess of 250)
- moves vertically and horizontally
56
two types of jet streams
- polar jet
- subtropical jet
57
characteristics of jet streams
- greatly influence weather patterns
- average height of 30,000 MSL
- wind speeds 100 - 150 kts (can reach in excess of 250 kts)
- 1,000 - 3,000 miles long
- 100 - 400 miles wide
- 3,000 - 7,000 feet deep
- move west to east
58
Valley wind
idk
59
Mountain wind
idk
60
dew point
the temperature that saturation occurs
61
difference between temperature and dewpoint
- dew point depression
- temperature dew point spread
62
relative humidity
percentage of the air saturation
63
3 characteristics of precipitation
- showers
- continuous
- intermittent
64
Characteristics of showery precipitation
- starts/stops
- changes intensity or sky conditions rapidly
- associated with cumuliform clouds
65
Characteristics of continuous precipitation
- steady
- gradual change
- associated with stratiform clouds
66
Characteristics of intermittent precipitation
- starts/stops at least once per hour
- can be showery or steady
- associated with both cumuliform and stratiform
67
precipitation forms
- rain
- drizzle
- frozen
68
how are clouds generally categorized
- high
- middle
- low
69
characteristics of low clouds
- surface to 6,500 agl
- hazardous to flight b/c of proximity to ground
- turbulence: non-moderate
- precipitation: drizzle or light rain
- if below freezing: can produce icing (accumulates faster due to clouds being denser)
70
characteristics of middle clouds
- 6,500 to 20,000 agl
- names contain "alto" prefix
- composed of ice crystals, water droplets, or a mix
- rain, snow
- icing is common
- turbulence may be encountered
71
characteristics of high clouds
- 20,000 to 40,000 agl
- names contain "cirro" prefix
- composed of primarily ice crystals
- contain no precipitation
- not an icing hazard
- little effect on flight ops except for mod turbulence
72
Special clouds (types)
- towering cumulous
- cumulonimbus
- nimbostratus
73
Cumulous & Cumulonimbus cloud characteristics
- found in low to middle and extend the the high cloud heights
- nearing thunderstorm stage
- produce heavy, showery precipitation
- mod turbulence
- icing common above the freezing level
74
Cumulonimbus cloud characteristics
- also referred to as "CB"
- very dangerous
- severe turb
- hail/icing
- lightening
- If extends past tropopause = severe thunderstorm
75
Nimbostratus cloud characteristics
- bases can be as low as 1,000 AGL
- heavy, continuous rain, snow, or ice pellets
- poor visibility
- low ceilings
76
What is denser, cold or warm air?
cold air
77
Four methods that air masses are lifted
- convergence
- frontal
- orographic
- thermal
78
convergent lifting
two air masses or parts of a single air mass converge
79
frontal lifting
cold fronts moving through the an area, lifting the warm front over it
80
orographic lifting
wind against a mountain side pushing up
81
thermal lifting
(Convective lifting) warm surface pushing cold air up by "intense solar heating"
82
Conditions you'd expect when stratiform clouds are present
- smooth air
- poor visibility
- steady winds
- steady precipitation
- rime icing
83
Conditions you'd expect when cumuliform clouds are present
- rough air
- good visibility
- gusty winds
- showery precipitation
- clear icing
84
Inversions, low clouds, fog, rising temps while climbing would indicate what conditions
stable
85
dust and rapidly decreasing temps while climbing would indicate what conditions
unstable
86
Define air mass
Body of air with uniform temp and moisture conditions
87
temperate zone
region between 30 and 40 deg North latitude (US)
88
Air masses are named according to their ___, ___, and ____.
moisture content; location; temperature
89
What indicates stability of air mass
temperature
(warm = stable, cold = unstable)
90
Surface front
point where front comes in contact with the ground
91
frontal zone
area that encompasses the weather on either side of the front
92
3 characteristics of fronts
- always located in a trough of low pressure
- cold fronts are faster than warm fronts
- frontal passage is usually accompanied by a 90 deg shift in wind direction
93
Flying through a front can show the following indication
- initial pressure decrease, then rises immediately (after frontal passage)
- wind shift (possible severe wind shear)
94
What clouds produce steady precipitation and little to no turbulence
Stratiform
(PREVIOUS TEST QUESTION --> OPTIONS MIGHT INCLUDE NIMBOSTRATUS AND STRATUS. ANSWER IS STRATUS)
95
What clouds produce showery precipitation and turbulence
cumuliform
96
How does the angle of the frontal slope influence weather
steep - generally associated with severe weather, showery, move fast
shallow - extensive cloudiness with steady precipitation
97
describe a cold front
more dense (wedges under warm air), steep slope, associated with unstable conditions when met with warm front
98
Signs a cold front is passing through
generally wind speed increased, baro pressure decreases-then rises sharply, lower cloud bases and rain/snow, win shifts 90 deg SW to NW, then clear skies and fair weather
99
Fast moving cold front occurs in a _____.
narrow band (sever)
100
Slow moving cold front occurs in a _____.
larger area (less severe, lasts longer)
101
squall line
- line of violent thunderstorms (dashed-double dotted purple lines)
- develop 50-300 miles ahead of cold fronts (sometimes nowhere near)
- very dangerous
102
Warm frontal passage characteristics
- overtakes colder air by going over the top (creates broad area of cloudiness)
- steady precipitation
- reduced visibility
- typically slower than cold fronts
- SE to SW wind shift
103
Stationary front
- frontal boarder between air masses show little or no movement (neither replacing each other)
- 180 deg wind shift
- weather similar to warm front but less intense
- weather of a stationary front may last for several days
104
how far ahead of a warm front can the associated cloud system reach?
500-700 miles
105
Occluded fronts
- form when a faster moving cold front overtakes a slower moving warm front
- 180 deg wind shift
- associated weather will be a combination of both types
106
difference between cold and warm occluded fronts
depends on which front remains in ground contact
107
Where is the most severe weather located in an occluded front?
100 miles south to 300 miles north of the frontal intersection
108
what is a dry line
"dew point line" is a boundary between moist and dry air masses
109
describe a dry line
- dense dry air wedges under the moist air
- temp will be similar on both sides (not a large temp gradient)
- a rapid rise in moist air can result in severe weather (tornados, hail, high winds)
110
What are the two groups of icing
Structural and engine icing
111
When does structural icing occur
formation of ice through clouds or liquid when the air and skin temp is equal or less than 0 deg C
112
what is the main concern for structural icing?
loss of aerodynamic efficiency due to an increase in drag and decrease in lift
113
engine icing is also known as what
induction icing
114
when does engine icing occur
when ice forms in the induction or compressor sections of the engine
115
what is a result of engine icing
FOD and compromised performance
116
Sources of moisture in regards to icing
- super-cooled water droplets
- wet snowflakes
-clouds (most common)
117
what are super cooled water droplets
water droplets that retain liquid form although temp is bellow freezing (0 to -20, in some cases -40 deg C)
118
True or False
Icing is possible in temps above freezing
True
119
3 types of Icing
- Clear
- Rime
- Mixed
120
What is a major factor in aircraft icing
The shape of the aircraft
121
Characteristics of clear Icing
- between 2 to -10 deg C
- lumpy and translucent/clear smooth
- supercooled drops not freezing right away upon contact
- tends to form horns or other complex shapes
122
Characteristics of rime icing
- between -10 to -15 deg C
- rough, milky, opaque
- formed by the supercooled droplets freezing instantaneously
- conformal or wedge-shaped accretions
123
Mixed Icing
- between -15 to - 20 deg C
- combination of clear and rime
- when ice particles become embedded in clear ice
- very rough/whitish
- accumulates rapidly and tough to remove
124
Icing generally found in cumulus clouds/unstable conditions
Clear icing
125
Rime is dependent on what
low rate of catch of small supercooled water droplets
126
Where does rime icing accumulate
edge of wings, antennas, pitot tubes, etc
127
What icing typically forms when flying through stratiform clouds/stable conditions
Rime icing
128
Where could you expect mixed icing?
colder portions of cumuliform clouds
129
Different severities of icing
- trace
- light
- moderate
- severe
130
trace icing
- Ice becomes visible
- accumulation slightly greater than sublimation
- occasional use of anti ice
131
light icing
rate of accumulation (¼ inch in 15-16 minutes) requires occasional use of ice protection systems to prevent accumulation
132
moderate icing
- rate of accumulation (¼ inch in 5-15 minutes) requires frequent use of ice protection systems to remove/prevent ice
- unless actions taken, significant build ups of ice on airfoil and may present problem
133
Severe icing
- the rate of accumulation (¼ inch in less than 5 minutes) ice protection systems fail to remove accumulation of ice
- usually a product of a clear or mixing icing encounter
- may require immediate diversion
134
There is a definite possibility of ______ icing, usually _____ or _____, within _____ to _____ miles ahead of a warm front.
moderate icing; mixed or clear; 100 to 200 miles
135
Light rime can be noticed in the _____ up to _____ miles ahead of a warm front surface.
altostratus; 300 miles
136
What front would be considered to have more of localized/spotty area of icing?
cold front
137
_____ icing is usually limited to supercooled cumuliform clouds within _____ miles to the ____ of the cold front surface position.
clear icing; 100 miles; rear
138
ice accumulation will have what affects on aerodynamic surfaces (7)
- decrease climb rate
- decrease cruise speeds
- increase stall speed
- decrease service ceilings
- decrease missed approach performance
- increase fuel consumption
- decrease max range
139
When icing is encountered, you should do what?
Climb or descend to exit icing condition
(POSSIBLE EXAM QUESTION: ANSWER IS SUPPOSEDLY "CLIMB")
140
Many times, it is more expedient to (a.) climb or (b.) descend above/below the moisture
climb above
141
how are the static ports protected on T-6A from icing
airframe location
142
how is the fuel system protected on T-6A from icing
external fairings
143
How do you deice the canopy and what are the limitations?
heating; 150 deg F
144
The most profound degradation of structural icing that manifests on aircraft performance usually occurs within _____ of ice accretion.
the first few minutes
145
Visibility can be reported as (units)
statue miles, hundreds of feet, meters
146
flight visibility
visibility from the cockpit
147
Prevailing visibility
- overal visibility
- "greatest horizontal vis equaled or exceeded throughout at least half the horizon circle"
- not continuous - merely needs to be at least half the horizon
148
Slant range visibility
- visibility from the cockpit to the ground
- it must be reported in a PIREP
- can be estimated by meteorologists
- indicates when aircraft will break out on final
149
RVR (runway visual range)
- max distance that the runway/lights can be seen from a position above a a specified point on its centerline
-reported in feet or meters
150
SKC/CLR sky cover
0
151
FEW sky cover
> 0/8 - 2/8
152
SCT sky cover
3/8 - 4/8
153
BKN sky cover
5/8 - 7/8
154
OVC sky cover
8/8
155
A ceiling refers to what
OVC, BKN, or obscuration
156
what does VV006 mean
vertical visibility of 600 feet
157
Two main types of fog
- radiation fog
- advection fog
158
other types of fog (not radiation or advection)
- upslope
- frontal fog
- freezing fog
159
Radiation fog
- developed only at night
- dissipating by late morning
160
advection fog
- fog in motion (generated in one spot, wind takes it somewhere else)
- typically coastal areas
161
upslope fog
- adiabatic cooling of rising air
- warm air forced up a slope by wind
162
frontal fog
- conjunction with a frontal surface
- precipitation induced (evaporation of falling rain)
- warm frontal/stationary fog has greatest impact on aviation ops
163
freezing fog
- air temp is below freezing
- if dense enough, may produce ice on aircraft surfaces
164
conditions for fog to form (3)
- condensation nuclei
- air must have high water content
- light surface winds (less than 10 kts)
165
When will fog start to form?
when temp and dew point are about 5 F 3 deg C from another
166
what are the ICAO indicators of a possible encounter with volcanic ash?
- odor
- haze
- changing engine conditions
- airspeed
pressurization
- static discharges
167
List some effects of a thunderstorm
- turbulence
- downburst
- microburst
- tornadoes
- icing
- lightning
- hail
- heavy rain
- surface wind gusts
- bad visibility
168
Thunderstorms are formed by a process called ______
Convection
- the transport of heat energy
169
what is needed to produce a thunderstorm (needed for convection)
- moisture
- lift (upward development)
- instability
170
what is commonly experienced around thunderstorms
turbulence (often exceeding the performance capability of most aircraft)
171
Gust front
line of dangerously gusty winds created on the leading edge of the advancing thunderstorm
172
roll cloud
- tube shaped
- along gust front and frequently on the leading edge of thunderstorms, cold front, or line of squats
- indicate shearing effects of different air masses
173
wall clouds
- abrupt lowering from a cumulonimbus cloud
- mark lower portion of a very strong updraft
- can proceed tornadoes if rotation is present
174
Clouds that indicate low level wind shear, extreme turbulence, and occur in fast moving thunderstorms
roll and wall clouds
175
Clouds that indicate low level wind shear, extreme turbulence, and occur in fast moving thunderstorms
roll and wall clouds
176
Hail size that can cause significant damage to acft in a few seconds
larger than ½ to ¾ of an inch
177
How is lightning formed
- satiric charges
- negative charge at the bottom and a positive charge at the top of the cloud
- positive charge on the ground, eventually a circuit is created and a discharge takes place
178
where do lightning strikes on aircraft commonly occur?
within 5,000 ft of the freezing level
179
hail process
water is lifted by warm updraft, freezes, falls back down, then either repeats going up and down or continues down (can be yeeted out the tow of the cloud too)
180
St. Elmo's Fire
when enough static buildup causes a discharge (plasma) between an object and the air around it
181
What hazards are associated with lightning?
- structural damage
- flash blindness
- static build up
- fuel ignition
182
Roll and wall clouds indicate
a severe fast moving thunderstorm
183
Tornado characteristics
- up to 1 ½ miles wide
- winds can reach up to 300
- tornado itself can move 30-40 kts
184
Most accurate means of tracking thunderstorms
NEXRAD (Next Generation Radar)
185
What is a TVS
Tornado Vortex Signature
186
Severe thunderstorms should be avoided by how many miles?
20
187
If you have to penetrate a thunderstorms what should you adhere to?
- penetrate perpendicular
- penetrate below the freezing level
or above -15 deg C level
- Min altitude should be 4,000-6,000 AGL above highest terrain
188
Be at least _____ feet higher than the top of the storm for every 10 knots of wind speed at the cloud top.
1000
189
What is a microburst
- sinking air formed by a thunderstorm
- less than 2.5 miles in diameter
- wind speeds as high as 150 mph
- flow velocities can reach over 6,000 ft/min
190
Development mechanisms of a microburst
- Cooling beneath thunderstorm cloud base
- sublimation
- evaporation
- existence of rain and/or hail
191
Viable ways to recognize microburst conditions
- Visual
- Instrument
- PIREPS
192
Visual cues of a microburst (4)
- Virga
- localized blowing dust
- shaft of rain
- severe thunderstorms/cumulonimbus clouds
193
Frequency of METAR observations
hourly, between 55 to 59 minutes past the hour
194
Two sections of a METAR
Body and remarks
195
When are SPECI's issued
when critical data of a METAR observation has changed from the previous observation
196
What does the "COR" in place of "AUTO" mean in the report modifier mean?
When a corrected METAR or SPECI is transmitted
197
AO1 and AO2 meaning
equipment used to accomplish the observation
(precipitation sensitivity)
198
Wind speeds on a METAR are displayed on a ___ min average
2 min
199
When would you see RVR listed on the METAR
- when prevailing visibility is less than or equal to 1 SM
or
- RVR for designated instrument runway is less than or equal to 6000 ft
200
observation area METARS cover
- 5 SM
- "unless directed elsewhere for thunderstorms/lightning"
201
Where can you look up remark codes for a METAR?
AFM 15-111
202
Period of time a TAF covers
- usually 30 hours (sometimes 24)
203
The "best projection" of weather for your ETA +/- 1 HR
TAF
203
The "best projection" of weather for your ETA +/- 1 HR
TAF
204
Area that a TAF covers
5 SM
204
Area that a TAF covers
5 SM
205
When is VRB used in a TAF
- wind speed is 6 KTS or less
- not possible to forecast a single wind direction (thunderstorms)
206
what does "9999" in a TAF mean?
7 SM visibility or greater is forecasted
207
when are obstructions/weather conditions included in the visibility of a TAF
vis is forecasted to be 9000 meters or less
