UK Met for Oral Flashcards
What information may a controller pass without it coming from the Met Office?
(1) Indicated wind direction and speed where anemometer indicators are fitted in the control room;
(2) RVR observations;
(3) Sudden or unexpected deteriorations of which a controller considers it advisable to warn aircraft immediately;
(4) Information from an aircraft in flight may be passed to other aircraft - the controller shall state it is from an aircraft in flight and the time;
(5) Special Aircraft Reports of meteorological conditions which affect safety;
(6) Cloud echoes observed on PSR;
(7) Observations made at aerodromes by personnel who hold a Met Observer Certificate;
(8) Observations made at aerodromes without accredited observers are not regarded as official reports.
If transmitted to aircraft or disseminated beyond the aerodrome, the message must be prefixed by: “Unofficial observation from (name of aerodrome) at (time) UTC gives (observation)”.
How are RVR’s transmitted to A/C?
Before approach begins, until aircraft lands.
Departing aircraft: until take-off.
If value more than maximum that can be measured:
“RVR is greater than …………………. metres.”
If no lights visible:
“RVR less than …………………………… metres,” (insert value for one light).
➢IRVR values passed at the beginning of each approach for landing.
➢Significant changes (one increment or more) to be passed until aircraft landed.
➢Current RVR to be passed before take-off.
RTF example
“RVR runway 26, 650 – 500(hundred) – 550 metres”
If only two values, identify individually:
“RVR runway 26,Touchdown 650, stop end 550 metres”.
How do you transmit the unserviceability of the IRVR?
“RVR runway (designator) Touchdown not available, mid-point 600 - stop end 400 metres”
➢Two transmissometers U/S: Remaining can be used provided if it is not “stop end”.
➢System totally U/S if “stop end” only value, revert to human observer method.
➢Change runway: “stop end” becomes “touchdown”, system can be used.
What are LVO?
Low Visibility Operations
- General term for airside operations in conditions of reduced visibility or low cloud
- Consists of low visibility safeguarding and low visibility procedures (LVPs).
What is Low Vis Safeguarding?
Prepares the aerodrome for low visibility procedures.
What are LVP’s?
Low Vis Procedures
- Actions carried out by ATC / aerodrome operator in respect of aircraft operations and vehicle movements.
- Includes restricting access to the manoeuvring area, protection of the ILS critical and sensitive areas and a reduced aircraft movement rate.
- Commencement varies from one aerodrome to another depending on local conditions and facilities available.
- Required for operations in lower than standard category I, other than standard category II, category II and III approaches and low visibility take-offs
Implementation of LVP’s does not ensure operations.
This still depends on numerous factors. Essentially these concern the following main areas:
- Flight crew complement, training, qualification and authorisation;
- Aircraft minimum equipment and certification;
- Aerodrome considerations; and,
- Operating procedures.
What is VOLMET?
VOLMET is a voice broadcast of a set of METARs broadcast on four frequencies covering different regions of the UK with each frequency transmitting a different METAR set. The four regions are London VOLMET (Main), London VOLMET (South), London VOLMET (North) and Scottish VOLMET. Details can be found in the UK AIP GEN 3.5.8.
What CAP governs MET reporting at aerodromes?
CAP 746
What must be sent in the event of an accident Met wise?
A full non-routine observation at the time of the accident, this is to ensure that complete details of the weather at the time of the incident will be available to an official enquiry.
What is a METAR and what does it include?
A report of actual weather conditions at a particular aerodrome at a specified time. Includes;
Surface wind
Surface vis
Any weather
Cloud
Air temp/ dew point
QNH
Remarks
- In Europe they include a trend forecast for the 2 hours following the METAR, in the UK this is not always the case.*
- Auto indicates that the METAR is prepared by Automated Observation systems.*
What is a SPECI?
An amendment to a METAR that draws attention to an improvement or deterioration of a condition that might affect the aerodrome ops.
Disseminated locally
Required following an accident.
What conditions trigger SIGMETS?
Thunderstorms
Heavy hail
Freezing precipitation
Tropical cyclone
Heavy sand/dust storm
Volcanic ash
Severe mountain waves
Severe icing
Severe turbulence
What is a TAF?
Terminal Aerodrome Forecast
A concise statement of expected meteorological conditions at an aerodrome during a specified period.
When is directional variation included on a met report?
If greater than 3kts and 60 degrees or more.
What does VRB mean on a met report?
Variable wind direction.
What does 0000 signify on a met report in regards to vis?
Vis less than 50m
When is vis variation reported?
When it is less than 1500m in one direction and greater than 5000m in another.
How is RVR denoted on a met report?
R followed by the runway and measured vis distance.
Distance in metres measured from 50m to 1500m
Letter P before distance means that it is higher than can be assessed.
Letter M before distance means that it is lower than can be assessed.
Mean values, U for trend improving D for opposite and N for no trend .
RVR tendencies and significant variations; and Wind shear groups (WS………) are not reported in the United Kingdom.
What types of clouds are notified on a met report?
Cumulonimbus and towering cumulus.
What does prob mean on a TAF?
Likelihood of proceeding change happening, 30 unlikely, 40 likely.
What validity periods can TAFs have?
9, 24 or 30
When are METARs issued?
Every 30 minutes at 20 past the hour and 10 to.
+
Heavy
-
Light
Bc
Patches
Bl
Blowing
Br
Mist
Ds
Dust storm
Dz
Drizzle
Fc
Funnel cloud
Fg
Fog
Fu
Smoke
Fz
Freezing
Gr
Hail >5mm
Hz
Haze
Ic
Ice crystals
Mi
Shallow
Pl
Ice pellets
Pr
Banks
Ra
Rain
Sh
Showers
Sg
Snow grains
Sn
Snow
Sq
Squalls
Ts
Thunderstorms
Va
Volcanic ash
Vc
Vicinity
Re
Recent
For what types of reports is abbreviated plain language used in met?
SIGMETS
TAF’s for some information
METAR or SPECI (trend group only)
What does 00000KT mean on a METAR?
No wind
What are the conditions for a gust?
When the wind is gusting to a speed 10 or more knots faster than the mean wind speed.
How are clouds reported on a METAR?
- Lowest cloud of any amount
- Next highest cloud of more than 2 oktas
- next highest cloud of more than 4 oktas
- Any CB/TCu present if not already reported.
- No significant clouds- NSC
What does M mean before temperatures on a METAR?
That the value is below 0°C
How is the QNH reported on a METAR?
Rounded down to the nearest whole hPa
What does NOSIG mean on a METAR?
No significant change
What does BECMG mean?
Becoming, from and till
What does TEMPO mean?
temporary change in conditions- from and till.
What does AMD mean on a TAF?
TAF amendment, used if a revised forecast is issued covering the remaining period of original TAF.
What does NSC mean on a TAF?
No significant cloud, can be used if all requirements of CAVOK or SKC cannot be met?
What does SKC mean?
Sky Clear
What does NSW mean on a TAF?
No Significant Weather
What are the conditions for CAVOK?
- VIS is 10km or more
- No minimum vis reported
- No cloud below 5,000ft or the minimum sector altitude which is greater
- No CB’s or TCU’s reported
- No significant weather in the vicinity of the aerodrome
What is cloud of operational significance?
A cloud with the height base below 5,000ft or below the highest minimum sector altitude, whichever is the greater, or a CB or a TCU at any height.
What is the definition of vis during the day?
The greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognized when observed a black background.
What is the definition of vis at night?
The greatest distance at which lights in the vicinity of 1000 candelas can be seen and identified against an unlit background.
Is AIRMET info issued for low level flight?
No
What does ‘AUTO’ signify on a METAR?
Tha is a report prepared by an automatic observing system.
Do we report RVR tendancies or wind shear groups in the UK?
no
Do UK METAR’s contain Trend groups?
They can, but don’t normally.
At what distance is visibility measured in km instead of m?
More then 5000m
Define visibility
The ability, as determined by atmospheric conditions and expressed in units of distance, to see and identify prominent unlighted objects by day and prominent lighted objects by night.
Either;
A) the greatest distance at which a black object of suitable dimensions, situated near the ground, can be seen and recognised when observed against a bright background;
(B) The greatest distance at which lights in the vicinity of 1000 candelas can be seen and identified against an unlit background; (SERA)
Define fog?
a suspension of small water droplets reducing visibility; To less than 1000m for fog
What is the prevailing visibility?
The maximum value reached or exceeded in at least 50% of the circle around the aerodrome, the sectors of visibility do not need to be contiguous.
The lowest visibility is also reported in the METAR when it is less than 1500m (providing it is not the prevailing visibility) or less than 50% of the prevailing visibility, along with its general direction.
What is the minimum visibility?
The minimum value of visibility, this will be reported on a METAR is the value is less than 50% of the prevailing vis or less than 1500m along with a general direction.
Define RVR and how it can be measured.
The actual visibility along the runway as viewed from the perspective of the pilot in the cockpit. It can be measured by counting;
- A series of marker boards along the side of the runway.
- A series of lights of known intensity along the side of the runway.
Human observer method above
-or by a photo-optical measurement of atmospheric transparency along the runway (IRVR), can have three Transmisometers at the touchdown zone, midpoint and stop end.
When is an RVR reported?
When local visibility is less than 1500m
or RVR readings indicate less than 1500m
What increments is visibility measure in?
- <500m= 50m intervals
- 500-5000m= 100m intervals
- 5km-30km=1km intervals
- 30km-70km= 5km intervals
- 70km>= greater than 70km (but who gives a shit if its that high)
When do you have to report the reasons for visibility reductions?
When the vis falls below 5000m
Define mist
a suspension of small water droplets reducing visibility; To not less than 1000m
