AV23: Weather in AAS - JB

Question 1

Define AWOS

Answer 1

Automated Weather Observation System
-set of meteorological sensors and associated systems designed to electronically collect and disseminate meteorological data.

Question 2

The minimum required observing and reporting capabilities of an AWOS to meet METAR and SPECI AUTO requirements

Answer 2

-Wind (direction, speed and gusts)
-Altimeter (include multiple sensors for fail-safe)
-Air Temp
-Dew Point
-Visibility
-Cloud Height
-Sky Coverage
-Precipitation
-Obstruction to Vision
-Thunderstorm detection capability
-Icing
Also, some may include RVR

Question 3

METAR and SPECI observations from AWOS include what word?

Answer 3

AUTO

Question 4

What information does LWIS provide?

Answer 4

Hourly report containing wind speed and direction, temp, dew point and altimeter.

Question 5

LWIS reports wind direction in degrees true, unless…

Answer 5

Unless it is using the VGSS (Voice Generator Sub-System)

which reports in degrees magnetic.

Question 6

AWOS reports TS at site if lightning detected where?

Answer 6

6SM or less from station.

Question 7

AWOS reports VCTS if lightning detected…

Answer 7

More then 6SM up to 10SM of site

Question 8

AWOS reports LTNG DIST if lightning detected…

Answer 8

More then 10SM to 30SM of site

Question 9

When is density altitude reported?

Answer 9

When it is 200FT or higher then aerodrome elevation.

Question 10

What are some limitations of AWOS?

Answer 10

• Reported visibility is taken unidirectional and so does not give prevailing vis
• For obstruction to vis, can only report FG, FZFG, BR, BLSN and HZ
• RVR not available at all stations
• Cannot report DZ or FZDZ (usually report as -RA or -FZRA)
• Does not report vicinity phenomena other then TS and lightning
• Cloud height measurement only possible to 10000FT
• only measures cloud directly over station, so may not give accurate sky condition
• Remarks are severely limited

Question 11

Weather to pass in the AAS

Answer 11

• Any occurrence of freezing rain, freezing drizzle, freezing fog, ice pellets (both type A and B) and hail
• Any occurrence of moderate or heavy precipitation
• Recent (RE) and in vicinity (VC) codes
• Rapid change in pressure
• presence of blowing or drifting snow
• TCU, CB, TS, FC, FC+, Squall line
• Lightning as appropriate
• Turbulence
• Low Level Wind Shear
• For IFR, ceiling less than 1000ft, visibility less then 3 miles
• For VFR, Ceiling from 1000ft to 3000ft, visibility 3-5 miles. if ceiling below 1000ft and/or visibility less then 3 miles, automatically invoke SVFR phraseology and procedures.

Question 12

What to provide if pilot requests latest weather

Answer 12

Tell pilot to contact Winnipeg FIC for latest weather and en-route information.
If pilot unable to contact FIC, provide current METAR/SPECI in full.
If pilot only requests specific elements, just give requested elements.

Question 13

Phraseologies for passing weather from METAR, SPECI and TAF.

Answer 13

METAR, March weather at XXXXz
SPECI, March special at XXXXz
TAF, March aerodrome forcast valid from XXXXz till XXXXz

Question 14

If a Flight Service Station has limited hours of operation and is not co-located with an AWOS, what rule must be used for pass TAF’s?

Answer 14

There must be 2 consecutive hourly observations done before the issue time of the TAF before a TAF can be passed.

Question 15

The difference between vicinity (VC code) qualifier in METAR as opposed to TAF

Answer 15

METAR - vicinity is withing 5 NM of station but not at station
TAF - vicinity means between 5 and 10 NM of the centre of the runway complex.

Question 16

TAF Code;

BECMG

Answer 16

Becoming, permanent change, gradual change.

Question 17

TAF Code;

FM

Answer 17

From, permanent change, rapid change.

Question 18

TAF Code;

TEMPO

Answer 18

Temporary, transitory change, fluctuation in weather elements

Question 19

TAF Code;

PROB

Answer 19

Probability, probability of occurrence of alternative values.
eg. PROB40 means probability of 40%
note, if PROB is more then 50%, will not use PROB, will be BECMG, FM or TEMPO instead

Question 20

When giving a pilot RVR, what must you include at the end?

Answer 20

Intensity of runway lights

Question 21

Reportable value increments for RVR

Answer 21

less the 300FT - reported as 300 "minus"
300 - 1200FT - increments of 100FT
1200 - 3000FT - increments of 200FT
3000 - 6000FT - increments of 500FT
more then 6000FT - reported as 6000 "plus"

Question 22

Pass RVR when?

Answer 22

• When RVR for intended runway is less then 6000FT
• When RVR varies by at least 1 reportable value above and below published take off and approach minimum
• When RWY lights setting of 4 or 5
• Ground visibility is 1 mile or less, report RVR is not available