Weather Flashcards
What is turbulence?
a sudden change in airflow by eddies (whirling motion of air) and currents.
Zulu time is _______
another name for Coordinated Universal Time (UTC), which is the time at 0° longitude at the Greenwich Meridian. It is used worldwide to avoid confusion arising from local time differences. By creating a ‘standard’ time, aviators all have a reference point to work from.
In the US, what countries do not switch to DST?
Arizona and Hawaii
For reasons of convenience and standardization, it was decided that the Earth would be divided into 24
time zones (each 15° wide).
15 degrees = 1 hour
Each time zone adopts the solar time of its _______
central meridian. In this way all countries and territories within the same time zone will assume the same time. They have the same standardized time. This standardized time for each time zone is known as Local Mean Time (LMT or only LT).
Some countries are so large that they may have more than one time zone.
There are several methods for naming the different time zones:
Using the number of its central meridian. Ex. 60° West Meridian Time
Using the letters A to Z (excluding J). Ex. Z Time
Using the position relative to time zone 0 (UTC). Ex. UTC +5, which is east of the prime meridian
Most of the times in the chart supplement are shown in _______
Zulu time
Behind the tower’s operating hours might be a plus plus symbol. One stacked on top of the other. _______
this symbol ‡ indicates that during periods of Daylight Saving Time (DST) effective hours will be one hour earlier than shown.
This tower operates from (1200 - 0300Z‡). If it’s DST and if the airfield is in the central time zone, what local times does the tower operate?
6:00 AM - 9:00 PM local time
The US observes DST from the _______
Second Sunday of March to the first Sunday of November.
FAA airport identifiers are only used for airports _______. Other countries and regions have _______
within the United States and its territories
their own systems for assigning airport codes:
ICAO Airport Codes - Used internationally, these 3-4 letter codes are assigned by the International Civil Aviation Organization (ICAO). The first letter(s) indicate the region or country, for example LFPG for Charles de Gaulle Airport in Paris.
IATA Airport Codes - Used widely in aviation, these 3-letter codes are assigned by the International Air Transport Association (IATA). For example, LHR for London Heathrow.
CADOR Codes - 4-letter codes used for airports in Canada. Assigned by Canada’s Department of National Defence.
EGCC Codes - 4-letter codes used for airports in the UK. EG stands for England, CC is the identifier for Cambridge Airport.
Russian Airport Codes - 3-4 letter codes used in Russia and former Soviet states.
So in summary, most countries have their own system for assigning airport identifiers rather than using the FAA system. However, ICAO and IATA codes are globally recognized standards used internationally alongside local coding systems. The FAA system applies exclusively to US airports and territories.
ICAO reserved the prefix _______ for the contiguous United States (all states from California to Maine and from Washington to Florida, but not Hawaii and Alaska). _______
‘K’
Therefore, both Hawaii and Alaska actually use the ‘P’ prefix, which is more commonly used in the South Pacific islands.
ICAO assigns unique 4-letter _______
location identifiers to airports, weather stations, and other aviation navigational aids globally.
FAA uses 3-letter _______
IATA codes domestically in US, but all US airports still have an ICAO 4-letter code
Both IATA and ICAO are _______
international organizations that oversee civil aviation operations. However, the IATA generally supports the airline industry, while the ICAO provides global standards for air transport operations.
A mile on the ground (sm) is _______
5,280 feet. A mile in the air (nm) is 6076.1 feet. This would mean a statute mile is smaller than a nautical mile. This would make sense because the farther we are from the earth’s center, the farther it is between two locations.
Overcast definition:
(of the sky or weather) marked by a covering of gray clouds; dull.
clouds covering a large part of the sky.
cover with clouds or shade.
Scattered definition:
occurring or found at intervals or various locations rather than all together.
occur or be found at intervals rather than all together.
Sky Conditions
So how is broken and overcast measured?
By something called “octals”, which are 8 equal segments of the sky. If the sky is covered between 5/8 and 7/8 with clouds, it’s reported as broken. And if it’s covered 8/8ths with clouds, it’s overcast.
SCT100 means?
scattered clouds at 10,000 feet
What dew point?
The temperature the air needs to be cooled to (at constant pressure) in order to achieve a relative humidity (RH) of 100%. At this point the air cannot hold more water in the gas form.
In METAR, the dew point depression is?
temperature minus dew point
when the dew point is well below the current air temperature, _______
moisture levels and relative humidity are lower and not a significant concern.
Adjusting the altimeter from 29.92 to a reported 29.58 setting gives you the _______
true altitude, because it accounts for the lower pressure.
Using the reported setting corrects for non-standard atmospheric pressures due to weather.
A precipitation discriminator is _______
a device that can detect the type and intensity of precipitation. This allows the station to report if precipitation is rain, snow, drizzle etc.
Standard airplanes will use MSL to?
To specify how high an airplane is to another to avoid crashing
True Altitude - _______
The vertical distance of the aircraft above sea level. It’s often expressed in MSL (mean sea level) or possibly ASL (above sea level). Aeronautical charts use true altitude to show airports, terrain, and obstacle elevations.
Heat sometimes causes the airplane to go up and _______
down, so be ready
The most common types of altimeters are _______
barometric. They determine altitude by measuring air pressure
Aeronautical charts are _______
all sorts of maps used for air navigation and include topographic features, hazards and obstructions, height of obstructions, navigation routes or airways and aids, airspace, and airports.
There can be VFR and IFR aeronautical charts, sectional charts, VFR sectional charts, and
If the air pressure falls, the aircraft will perform as if it is at a _______
higher altitude, or is said to be performing at a higher pressure altitude
Water vapor present in the atmosphere on humid days reduces _______
the density of air
At higher altitudes above sea level an aircraft will have _______
worse performance
At sea level, air pressure averages _______. That means _______
29.92 inches of mercury
a glass tube, with its air pumped out and sealed at its upper end and placed in a dish of mercury at its lower (open) end, would have mercury pushed by air pressure up to a height of 29.92 inches in the tube.
Pressure altitude is the altitude _______
at which a given atmospheric pressure corresponds to the standard atmospheric pressure at sea level. Or an imaginary altitude an aircraft is assumed to be flying at, to describe that the aircraft will perform as if it were at that altitude in its real altitude because the current atmosphere pressure deviated from the standard atmosphere pressure. Or the altitude indicated when the altimeter is set to 29.92, because it’s as if you were flying at that altitude when it’s adjusted
Density altitude is _______
pressure altitude corrected for non-standard temperature and humidity
Even though two aircraft may be at different true altitudes, if they are at the same pressure altitude, _______
they will experience the same aerodynamic and engine performance.
Density altitude is used to determine aircraft performance _______
calculations for flights. It is used when landing, taking off, and in flight. It also allows you to determine the amount of runway you need on a non-standard day.
METAR data refers to _______
aviation routine weather reports that are issued hourly for airports around the world. The different sections of this OU example METAR report have the following meanings:j
- METAR - type of report
- KOUN - Station identifier/FAA identifier
- 121235Z - Date and time of report
- AUTO - modifier
- 15013KT - wind
- 10SM - visibility
- TSRA BR - weather
- BKN008 OVC014 - sky condition
- 18/15 - Temperature and dew point
- A2958 - altimeter setting
RMK SLP201 - remarks
METAR - _______
type of report
KOUN - _______
Station identifier, in this case University of Oklahoma Westheimer Airport. The first letter indicates the region the airport is located in - K for airports in the continental US, C for airports in Canada, etc. Second letter corresponds to the state name. The last two are a unique sequence assigned to this airport.
121235Z - _______
Date and time of report, 12th day of the month at 1235 UTC
AUTO - _______
Automated report with no human intervention
15013KT - _______
Wind direction 150 degrees (the direction that the wind is coming from, measured in degrees), wind speed 13 knots. Another example which includes gusts: 12016G21KT - wing direction 120 degrees, prevailing wind speed 16 knots, and gusts up to 21 knots
10SM - _______
Visibility 10 statute miles
TSRA BR - _______
weather. Thunderstorm with heavy rain. BR - Mist. The order of weather groups approximately indicates the predominance of each phenomenon.
Some other common weather group codes:
RA - Rain
SN - Snow
FG - Fog
HZ - Haze
DU - Dust
SA - Sand
FU - Smoke
OVC014 - _______
Sky condition overcast at 1,400 feet. There are other sky condition codes that can be reported such as:
SCT = Scattered clouds
BKN = Broken cloud cover
OVC = Overcast
FEW = Few clouds
CLR = Clear below 12,000 feet
SKC = Sky Clear (no clouds detected)
The three-letter code is then followed by the cloud height in hundreds of feet.
Some key differences:
SCT means 3/8 to 4/8 cloud coverage, with breaks
OVC means 8/8 cloud coverage, fully overcast
BKN is 5/8 to 7/8 cloud coverage, more solid than scattered
18/15 - _______
Temperature 18°C, dew point 15°C
A2958 - _______
Altimeter setting 29.58 inHg
RMK - _______
Remarks section follows. It provides additional meteorological data that didn’t fit in the main body of the report. The RMK remarks section is optional and will not always be present in METAR reports. If RMK is included, it means all groups after it are remarks with supplemental info. If RMK is not present, the METAR report ends after the final main group (altimeter setting, in most cases). Remarks can include things like precipitation amount, sensor status, lightning, sea level pressure, etc.
AO2 - _______
Automated station with precipitation discriminator. indicates information about the automated sensor equipment used to generate the METAR report. Specifically, AO - Automated station without a human observer, and 2 - Station has a precipitation discriminator. The number codes after AO provide details on the automated station’s capabilities:
AO1: No precipitation discrimination
AO2: Has precipitation discrimination
AO1V: Has precipitation discrimination and visibility sensor
SLP201 - _______
sea level pressure 1020.1 hectopascals (hPa). Meteorology, corrected to sea level and standardized temperature for analysis
T01770149 - _______
hourly temp 17.7°C dewpoint 14.9°C. Meteorology, high precision average.
The terms “station identifier” and “FAA identifier” _______
are often used interchangeably, but “FAA identifier” is more accurate.
Understand information they give you about weather on the _______
plane. Information about weather will be constantly changing. METARs
The attmosphere -
the air surrounding Earth - has weight and mass
The atmosphere is composed of _______
78 percent nitrogen, 21 percent oxygen, and 1 percent other gaseous elements like argon and helium
A flight control system has two ends:
One end is the pilot’s input to a control in the cockpit. The other end is the output that happens outside, which could be increased speed, lower speed, pitch up, pitch down, roll right, roll left, etc.
Implied in these are the mechanical, hydraulic, electrical, and other means connecting these two ends, and through which intended output can reliably happen
Pressure altitude is _______
True altitude corrected for non-standard pressure
Absolute Altitude -
The vertical distance of an aircraft above the terrain, or above ground level (AGL)
Hypoxia is _______
a condition caused by insufficient oxygen in the bloodstream. Symptoms are impaired reaction, judgement, confused thinking, fatigue, headaches, and sometimes euphoria; prolonged conditions can cause unconsciousness and eventually death. In aviation it’s typically caused because of unpressurized air at higher altitudes. It typically happens at altitudes above 10,000 feet above mean sea level. The FAA regulations only require oxygen for flights above 12,500 feet.
An increase in density in the air a plane flies through results in a what in which forces?
An increase in both drag and lift
An airplane travelling in the same direction as the wind experiences what in which forces?
Lower levels of lift and drag
How does ice accumulated on the aircraft’s wings affect the stall speed?
Increase
TAF (Terminal Aerodrome Forecast)
a TAF report provides the same weather information as a METAR, plus information relating to whether rapid, gradual or temporary change is expected in some of the meteorological conditions.
Notices to Airmen (NOTAMs) are _______
informational advisories filed by airports to transmit safety-critical, time-sensitive updates to pilots regarding any change in conditions, procedures or hazards at that particular airport.
During the summer months, what situation might cause you to delay flying?
The presence of local thunderstorms. Thunderstorm activity peaks during summer.
What is considered the lowest practical visibility under VFR
3 miles
_______ offers the clearest air of the four seasons
winter
At winter, since cold air is more dense than warm air, aircraft performance _______
will be at its peak.
Brisk wind conditions is a reason to _______
postpone flying
Ideally you always want to take off and land _______
into the wind. But this won’t always be possible, and this is why learning to fly with crosswinds is important
The minimum ceiling height under VFR is?
1,000 feet AGL
The ceiling is _______
the lowest cloud layer that covers most of the sky
Overcast ceiling is _______
a solid cloud cover
Broken ceiling is _______
just an overcast with a few holes in it.
