Wind Information
Complete the following MATS reference:
When gusty wind conditions are obtained from reports or observed on direct reading instruments...
When gusty wind conditions are obtained from reports or observed on direct reading instruments, issue the wind direction and speed of gusts.
"WIND (direction) AT (speed) GUSTING (speed)."
Gusty wind conditions are critical to pilots conducting an approach using auto-throttle or during crosswind conditions. The nearer to 90o the angle between wind direction and runway alignment, the lower the maximum acceptable wind speed for the aircraft.
Define PIREP
A report by a pilot pertaining to weather conditions encountered in flight.
NC-SWOP 3.5 - Visibility at night
(fill in the blanks)
Visibility at night shall be determined with ____________________________.
Recorded visibility ____________ be reduced on account of _____________.
Visibility at night shall be determined with the aid of markers in the form of lights.
Recorded visibility shall not be reduced on account of darkness alone.
Reporting Significant Differences in Reported and Observed Weather Conditions
Report significant differences between aviation weather reports and controller-observed weather conditions or PIREPs to:
- Concerned aircraft
- The position responsible for disseminating weather information, if applicable
- Other concerned sectors/units
- The appropriate FIC
NC-SWOP: Prevailing Visibility
It is the maximum visibility value common to sectors comprising one half or more of the horizon circle.
The most common weather observers on controlled airports in Canada are:
- Flight Service Specialists (FSS)
- Contract Weather Observers (CWO)
- Automated Weather Observations (AWOS)
- Limited Aviation Weather Observations (LAWO)
TC AIM AIR 1.5.3 - Incorrect Setting on the Subscale of the Altimeter
- A too high subscale setting means a too high altimeter reading, that is the aircraft would be at a level lower than the altimeter indicates
- A too low subscale setting means a too low altimeter reading, that is the aircraft would be at a level higher than the altimeter indicates.
NC-SWOP 3.6 - Determination of prevailing visibility
(Complete the reference)
To determine prevailing visibility, the horizon circle shall...
To determine prevailing visibility, the horizon circle shall be divided into as many sectors as there are different values of visibility. The highest visibility value that is common to sectors which cover one half or more of the horizon circle shall be taken as the prevailing visibility.
> Discrepancies in AWOS information might include any of the following:
- AWOS ceiling or visibility and that observed by an accredited weather observer
- AWOS ceiling or visibility and that reported by a pilot in the vicinity
- AWOS visibility and that observed by an airport controller.
NC-SWOP Definition: SPECI
An aerodrome Special Meteorological report reported when selected changes in weather conditions significant to aviation occur off the hour.
> Wind direction is indicated in magnetic or true degrees as follows:
- On direct reading instruments and EXCDS in the SDA, direction is displayed in degrees magnetic
- On direct reading instruments and EXCDS in the NDA, direction is displayed in degrees true
- In METAR, TAF, and SPECI, direction is always displayed in degrees true.
Complete the following MATS reference:
Use the unit's direct reading altimeter as...
Use the unit's direct reading altimeter as the primary instrument for obtaining the local altimeter setting.
At locations where the direct reading altimeter is independent of the primary source digital barometer, verify its accuracy against the reference altimeter setting when opening the unit, if applicable, and at least once per shift.
> The reference altimeter setting may be obtained from the METAR or calculated using a primary source digital barometer.Issue information about a radar-observed weather area as follows:
"[size or extent of the area] (position) [MOVING (SLOWLY / RAPIDLY) ] [direction] (other information)."
The two limitations of AWOS versus a true manned observation.
1. AWOS is programmed not to overreact to changing weather conditions. This means that it can "lag" for a time in rapidly changing conditions.
2. AWOS cannot apply human logic to an isolated phenomenon (i.e. something occurring only in the vicinity of the sensor such as fog or plowed snow from snow blowers).
NC-SWOP Definition: METAR
The name of the international meteorological code for an Aviation Routine Weather Report. METAR observations are normally taken and disseminated on the hour.
Using Other Sources for Wind Information
When you extract wind data from the local METAR, SPECI, or automated observation, issue:
- Time
- Wind direction and speed
- When issuing wind data extracted from an automated observation, you need not say AUTOMATED.
When you normally use a direct reading instrument but it is unserviceable, you must convert the wind direction that is extracted from the local METAR, SPECI or automated observation from degrees true to degrees magnetic.
PIREPs enhance weather briefings, as they supplement aviation weather reports. In addition, they are used by meteorological personnel when preparing forecasts. PIREPs should be relayed in the following format:
- Position
- Time
- Altitude
- Type of Aircraft
- Meteorological conditions observed
Prefix weather information with the appropriate term:
- Tower
- Pilot
- Automated
- Weather Report
- LAWO Ceiling
- Tower visibility
- Tower weather= "TOWER OBSERVES (weather information)
- Pilot = "PILOT REPORTS (weather information)"
- Automated = "(location) (time) AUTOMATED (report)."
- Weather Report = "WEATHER AT (time, weather information)."
- LAWO Ceiling = "TOWER CEILING (as determined by LAWO)."
- Tower visibility = "TOWER VISIBILITY (prevailing tower visibility)."
Aviation Weather Services Guide May 2017
(Complete the following reference)AWOS has a full suite of sensors that measures...
AWOS has a full suite of sensors that measures cloud base height, sky cover, visibility, temperature, dew point, wind velocity, altimeter setting, precipitation occurrence, type, amount and intensity, and icing.
LWIS is a more basic automated weather system, measuring only wind, altimeter setting, temperature and dew point.
Either system may be equipped with a voice generation module.
Ceiling
The lesser of:
- The height above ground or water of the base of the lowest layer of cloud covering more than half the sky
- The vertical visibility in a surface-based layer that completely obscures the sky.
When providing wind direction and speed:
- Use the values indicated in Wind Direction and Speed Values
- Express direction as a three-digit number indicating degrees.
- In the NDA, include the word TRUE after the wind direction data
- Express speed in knots. You may express the value in group form.
- The position designated responsible for disseminating weather information, if applicable
- If the weather is of significance, to:
o Concerned pilots
o Appropriate FIC
o Other concerned sectors/units
NC-SWOP 5.12.2 Layer amounts in okta and their abbreviations
- Sky Clear
- Few
- Scattered
- Broken
- Overcast
- Vertical Visibility
- Sky Clear = SKC (No layer with base present)
- Few = FEW (less than 1/8 to 2/8 summation amount)
- Scattered = SCT (3/8 to 4/8 summation amount)
- Broken = BKN (5/8 to less than 8/8 summation amount)
- Overcast = OVC (8/8 summation amount)
- Vertical Visibility = VV (8/8 summation amount)
Complete this MATS reference:
Advising the TOC when Tower-Observed Visibility is Reported Due to Localized Phenomena
When tower observed visibility is reported due to localized phenomena, a voice NOTAM is used to report the non-representative conditions of the AWOS visibility sensor.
If the phenomenon is expected to persist for more than one hour, advise the TOCC as a visibility non-representative NOTAM must be issued until the phenomenon subsides and the reported AWOS visibility returns to representative conditions.
Ground Visibility
With respect to an aerodrome, the visibility at that aerodrome as contained in a weather observation reported by any of the following:
- An ATC unit
- An FSS or FIC
- A community aerodrome radio station (CARS)
- An automated weather observation system (AWOS) used by the Department of Transport, the Department of National Defence, or the Atmospheric Environment Service for the purpose of making aviation weather observations.
- A radio station that is ground-based and operated by an air operator.