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.
“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?
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;
Air temp/ dew point
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.
Required following an accident.
What conditions trigger SIGMETS?
Heavy sand/dust storm
Severe mountain waves
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.