SAMRA (Radio Aids/Navigation) Flashcards
PSR transponder requirement and view limitations:
No transponder needed
- Used for weather
- Picks up birds
- 80NM range
How is SSR used?
Uses time interval between interrogation and reply from aircraft transponder
pressure altitude, longer range
Transponder up to 250NM range
What is TSR?
Terminal service radar
What is PAR?
Precision approach radar
What is mode A transponder?
Base, no altitude!
What is ADSE?
Airport surface detection equipment
What is mode C transponder?
Position with altitude encoding (pressure altitude in aircraft transponder)
What is mode S transponder?
A and C with TCAS abilities! S, TCAS
Two aircraft equipped with mode S and TCAS II can communicate to each other for RAs using the mode S transponder
Can send ADS-B messages
2 types of weather detection equipment:
- Weather radar unit
- Lightning detection unit (storm scope)
Advantages to storm scope:
- Not susceptible to the same attenuation as radar
- Tends to cost less
3. Not dependent on line-of-sight, able to detect lightning behind mountains - Possible to detect turbulence within clouds of little or no precipitation
- Stormscopes can provide an arc or 360 degree view of electrical activity of aircraft
Weather radar works on the basis of:
Primary surveillance radar
Uses a beam of energy sent out and reflects back towards antenna, shows target/echo
Reflects water! Top-down view, density/intensity of water
What type of precipitation is most reflective on a weather radar?
- Rain
- Wet snow
- Wet hail
designed for LIQUID precipitation
Least reflective: dry hail, ice crystals, dry snow
What type of precipitation is least reflective?
- Dry hail
- Ice crystals
- Snow
The amount of energy returned to the antenna on a weather radar is dependent on:
- Type of precipitation
- Concentration
- Water droplet size (returns the greatest energy)
Exam question will be which one of the three is the MOST reflective? WATER DROPLET SIZE
Where would you scan a thunderstorm to find its severity?
Lower half of storm!
Attenuation is based on what factors:
- Distance
- Further you are the more energy is lost use to beam dispersal and storm is understated - Heavy precipitation
- Radar energy is absorbed and cannot detect a cell behind the area of heavy precipitation
- This is where the tilt function needs to be used!
What does the gain function do?
Changes colours on map.
Up gain = show green as a yellow, yellow as red, etc.
Down gain = show magenta as red, red as yellow, etc.
You can use the gain (turn down) to find specific cells if your screen is showing entirely red.
does NOT change sensitivity!!!
Using a weather radar what would you look for to decipher a severe thunderstorm echo/target?
- Irregular shape
- Shape is rapidly changing
Indicates hail, severe turbulence, icing, wind shear, tornadoes
Ground based weather radar can detect what types of precipitation:
- Rain
- Snow
- Drizzle
- Hail
does NOT detect volcanic ash!
What types of imagery are available for ground based weather radar?
Precipitation rate for SNOW (INCLUDING HAIL)
or
Precipitation rate for RAIN (INCLUDING VIRGA)
Echo tops
Ground based weather radar modes:
- National
- Regional
- Single
Source of aviation weather in Canada:
NAV Canada
Compiles all weather in the world, they just collect it all to display
When are GFAs issued?
Approximately 30min before the beginning of the coverage period
for ALL 6 GFAs!!!! It’ll show the issuance time for each one and all 6 read the same time!
GFA:
Time observed:
1800Z, 0000Z, 0600Z, 1200Z (remember the order!)
Time issued:
Approximately 30min before the beginning of the coverage period
Altitude concerned:
AT or below 24,000ft, can include convective weather above FL240
Remarks:
Graphically depicts forecast weather over a period of time, do NOT forget about the IFR outlook and its addition to its total validity time
- Each GFA is valid for 12hrs
Difference between AIRMET and SIGMET:
SIGMET
Short-term weather warning issued where hazardous conditions are occurring or are expected to occur. Conditions are occurring, more severe.
- SFC winds >50kts
- squall line
- tornadoes
- volcanic ash
AIRMET
Short-term weather advisory of potentially hazardous conditions that are not in a current GFA and not requiring a SIGMET. Potential, not as severe.
- OUTSIDE OF CONVECTIVE ACTIVITY:
- low visibility
- moderate turbulence
- moderate icing
SIGMETS AND AIRMETS CAN AMMEND GFAs!
When are TAFs issued?
Approximately 20mins before the beginning of the validity period
TAF validity periods:
Issued every 3-6hrs
Valid for 12, 24, or 30hrs; next valid time is stated at the end of the TAF
Upper level forecast chart (PROG) time issued, applicable flight levels and its depiction:
NWS in Washington responsible
2 FORECASTS
FL240 to FL450
- FL240,FL340,FL390,FL450
6 and 12hr forecast produced every 6hrs
Wind & temperature chart
NOT Canadian
Significant weather forecast chart (PROG) time issued, applicable flight levels and its depiction:
- Issued approximately 11-12hrs before validity time of 00Z,06Z,12Z,18Z (not amended unless a SIGMET updates sig wx prog)
- For Canada FL100 to FL240 (700mb to 400mb)
- Altitudes depicted in box square is the height of tropopause
SIGNIFICANT WEATHER FORECAST CHARTS ARE ISSUED BY WASHINGTON! THEY USE ICAO! IF YOU SEE FREQ,OCNL,ETC., ADD THE 25% BUFER TO COVERAGE!!!
Surface weather chart:
Time observed:
0000Z, 0600Z, 1200Z, 1800Z (4 times)
Time issued:
Issued 2-3hrs after observation, meaning an observation while the chart was valid; NOT current
Altitude concerned:
Surface to 3,000ft, including MSLP
Remarks:
Analysis of MSL pressure pattern, surface location of fronts, surface position of precipitation and obstructions to visibility (based on weather reports). Weather aloft that is visible from surface is also included.
Upper Level Chart pressure per chart and relative altitude:
850mb = 5,000ft
700mb = 10,000ft
500mb = 18,000ft
250mb = 34,000ft
What’s a VOLMET:
Network of radio stations that broadcast TAF’s, SIGMETs, and METARs on HF frequency Schedule based on 5min intervals which one station in each region broadcasting reports for a fixed list of cities in each interval.
5mins you’ll hear YVR
10mins you’ll hear YYJ
etc.
TAF,METAR,SIGMET on HF!
Where do you find the frequency for which a VOLMET is being played on:
CFS!
Where are METARs valid for?
ONLY VALID AT AERODROME! of station reporting!!
What does CCA mean in a METAR?
Correction
What is MI in a METAR?
Shallow
What is BC in a METAR?
Patches
What is SG in a METAR?
Snow Grains DO NOT GET CONFUSED WITH GS
What is GS in a METAR?
Snow Pellets NO NOT GET CONFUSED WITH SG
What is the difference between BR and FG in a METAR?
BR = visibility greater OR EQUAL TO 5/8SM
FG = visibility less than 5/8 SM
SKC:
No clouds present
FEW:
0 to 2 Oktas
SCT:
3 to 4 Oktas
BKN:
5 to 8 Oktas
OVC:
8 to 8 Oktas
CLR:
No clouds present below 10,000ft. Remember CLR is more restrictive, and SKC is the entire sky being clear
METAR CYFC 132100Z 26010KT 2SM -RA BR BKN030 OVC090 08/07 A2953 FG3 ST3 AC2 SLP994=
What is the minimum opacity increase for the surface based layer to constitute a ceiling?
5/8s
Fog does not constitute a ceiling, until it has 8/8 coverage!
SURFACE BASED WEATHER HAS TO BE 8/8 OKTAS FOR IT TO BE CONSIDERED A CEILING AT GROUND LEVEL; NOT 5/8 AS IT WOULD BE FOR A BKN LAYER AT ALTITUDE!
What is an LWIS? What information does it provide?
Limited weather information system. AWOS with basic weather
- Wind speed/direction
- Temp/dewpoint
- Altimeter
that’s it!
COCHRANE AUTOMATED WEATHER OBSERVATION 0123Z
WIND, 120 AT 5
TEMPERATURE 14, DEWPOINT 8
ALTIMETER 2994
When you are asked which GFA in sequence is the one you are looking at, how would you find that?
GFAs come in packs of 3, starting at:
1800Z
0000Z
0600Z
1200Z
If yours said 0600Z, your GFA would be the 3rd one in sequence from the issuance
What ceiling/visibility is considered IFR?
Ceilings 1,000ft AGL or less and/or Less than 3SNM
What are the validity periods of GFAs?
6hrs each, but note the last one:
If an IFR outlook is provided at the very bottom, not the validity period because that will be the validity period of the entire GFA!
Exam question:
Of a package of 6 GFAs, what is the entire validity period? 24 hours!! NOTE IFR OUTLOOK
What is the green dotted enclosed sections on a GFA?
Continuous precipitation
What is the green hashed enclosed sections on a GFA?
Showery precipitation
Define the yellow dotted enclosed areas on a GFA:
Areas of obstruction not associated with precipitation, where it is 6SM or less
ISOLD in GFA coverage of the sky:
25% or less of sky
Convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
50% or less in ICAO
ISOLD,OCNL,FRQ - Convective (I Sold Occasional Fent)
LCL,PTCHY,XTNSV - Non-convective
OCNL in GFA coverage of the sky:
26 - 50% of sky
Convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
51% to 75%
FRQ in GFA coverage of the sky:
Greater than 50% of sky
Convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
Greater than 75%
LCL in GFA coverage of the sky:
25% or less of sky
Non-convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
50% or less in ICAO
PTCHY in GFA coverage of the sky:
26 - 50% of sky
Non-convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
51% to 75%
XTNSV in GFA coverage of the sky:
Greater than 50% of sky
Non-convective
REMEMBER ICAO STANDARDS ARE DIFFERENT, ADD 25%.
Greater than 75%
What is the symbol for a trough on a GFA?
Purple dashed line, or double purple dashed line if upper trough
What is the wind speed and direction of the sock shown?
From the northwest at 20 gusting 30
Identify the differences between the turbulence sections on a GFA:
GFAs are amended by:
SIGMETs and AIRMETs! Draws attention to something that is occurring that was not forecasted
TAF validity periods:
12hr
24hr
30hr at very few airports
someone needs to be there to make it and make amendments to it if weather differs from TAF. Remember this as this will indicate a closing time for the control tower
Where are TAFs valid?
5NM from geographic centre of aerodrome. Do not be confused with METAR as a METAR is just above the airport its reporting from
VC in a TAF:
5-10NM
VC in a METAR:
Up to 5NM, but not at aerodrome
BECMG means:
A permanent change
How is this read:
WS011/27055
WS at 1,100ft AGL 270 degrees at 55
PROB 30/PROB 40 is an indication of:
Hazardous weather only!
9900 means what in an FD?
Light and variable
791159
What is this FD wind direction, speed and temperature?
79-50=29 = 290 degrees
111kts
- 59 degrees
792538
What does this FD mean?
SUBTRACT 50 from first number, ADD 100 to 2nd number!
290 @ 125kts! -38 degrees
Straight up add 100 to the 2nd number in the FD.
If an FD states “No forecast” why would this be?
Elevation of station reporting is above 3,000ft or whatever the elevation is
What altitude is an Upper Level Prognostic Chart issued at in Canada?
4 flight levels!
FL240,FL340,FL390,FL450
How often is an Upper Level Prognostic Chart issued?
Every 6hrs beginning at 00z
For example:
00Z analysis will provide a 06Z & 12Z forecast
06Z analysis will provide a 12Z and 18Z forecast
WAFCs generate high-level significant weather charts for FL___ to FL___ around the world
FL250 to FL630
When turbulence is indicated on a weather chart, what does it imply?
A greater than 50% chance of it occurring!
In a prognostic chart, why are some of the wind flags/penants upside down when following a jetstream?
They stick out into the colder air mass!
What is the jetstream delta on a prognostic chart?
A box under the green jet stream that tells you the depth and tops of the jet stream where the jet stream speed exists i.e. 80kts!
On a sig prog chart, a jet stream states the barbs indicating 150kts at its centre at FL300 and ranging from FL160 to FL340. What is the speed of the jet stream at FL190?
It would be 80kts because on the prog chart from Washington (the ones that plainly says Washington and ICAO) the jet streams that are depicted only start at 80kts and not 60kts like the other charts!!!
This is a JET STREAM DELTA!
Upper air analysis chart, what is different?
Anal charts show in tens of metres! You will be given a chart at a mb pressure and it will show your true altitude in metres above sea level.
Exam question will be in regards to a chart like this; if you fly through a high pressure, your true altitude will increase (you could memorize this or just look at the anal chart that shows your actual height in metres at that flight level)
CALLED CONTOUR LINES
How are isotachs spaced on an upper air anal?
Isotach = area of EQUAL WIND SPEED
Spaced at 30kt intervals; on anal legend
when 30kt isotachs are spaced closer than ___NM apart, there is sufficient horizontal shear for CAT
90NM apart!!!!!
Remember on upper air anal charts its measures equal wind speed. So an area where the isotachs/windspeed areas are densely close together, means horizontal shear for CAT. OR hard direction changes.
Every degree of latitude is___NM
60NM
On an eastern track you pick up winds from the northwest then from the southwest. What happens to your altitude?
Decreases then increases again, if you draw it out and connect the lines, it looks like you are flying around a low pressure system because it looks counter-clockwise (see picture)