Chapter 2

Weather Information

 TABLE OF CONTENTS

2.1 ATIS (Automated Terminal Information Service) *

2.2 RVR (Runway Visual Range) *

2.3 Volmet *

2.4 Altimeter settings *

2.4.1 Standard ICAO atmosphere *

2.4.2 QNH *

2.4.3 QFE *

2.5 Weather reports by pilots *

2.5.1 Icing *

2.5.2 CAT (Clear Air Turbulence) *

2.5.3 Spot wind *

2.5.4 Wind shear *

2.6 Annex 10, (Volume II) *

 

 

2.1 ATIS (Automatic Terminal Information Service)    Back to index

   Automatic Terminal Information Service, or better known as "ATIS", is recorded information that is broadcast continuously over a designated frequency. The Tower prepares this information to provide arriving and departing traffic information pertaining to active runways, weather conditions and Notices to Airmen (NOTAMS). The wind information in an ATIS transmission is given in a magnetic direction. When airport conditions change, the Tower will record a new report. When an ATIS report is recorded it is assigned a letter using the phonetic alphabet. When calling the tower, ground control or approach control the crew should acknowledge reception of: "information…" followed by the letter of the phonetic alphabet that is designated to the last ATIS transmission. This indicates to the controller that the latest ATIS transmission has been copied and repetition of weather information is avoided.

   ATIS transmissions are not available at all airports and not on a 24-hour basis. In Greece only major airports provide ATIS (Athens, Thessaloniki, Rhodos, Kerkyra, Kos and Iraklion).

  

 To ATIS είναι μαγνητοφωνημένες πληροφορίες, οι οποίες εκπέμπονται συνεχώς, απο μια καθορισμένη συχνότητα. Ο Πύργος Αεροδρομίου προετοιμάζει αυτές τις εκπομπές ώστε να παρέχονται στα αφικνούμενα και αναχωρούντα α/φη πληροφορίες σχετικές με τον διάδρομο εν χρήσει, μετεωρολογικές συνθήκες και NOTAMs. Οι πληροφορίες ανέμου σε μια εκπομπή ATIS δίνονται απο μαγνητική διόπτευση .Όταν οι συνθήκες αεροδρομίου αλλάξουν ο Πύργος θα μαγνητοφωνήσει μια νέα αναφορά. Όταν μια αναφορά ATIS μαγνητοφωνείται, της δίνεται ένα γράμμα του φωνητικού αλφαβήτου. Όταν το πλήρωμα καλέσει τον Πύργο ή τον Ground ή την Προσέγγιση πρέπει να γνωστοποιήσει λήψη των «Πληροφοριών...» ακολουθούμενο απο το γράμμα του φωνητικού αλφαβήτου που δόθηκε στην τελευταία εκπομπή. Αυτό καταδεικνύει στον Ελεγκτή οτι οι πιο πρόσφατες πληροφορίες έχουν ληφθεί και η επανάληψη αυτών μπορεί να αποφευχθεί.

    Οι εκπομπές ATIS δεν είναι διαθέσιμες σε όλα τα αεροδρόμια και όχι σε 24ωρη βάση. Στην Ελλάδα μόνο μεγάλα αεροδρόμια παρέχουν ATIS (Αθήνα, Θεσσαλονίκη, Ρόδος, Κέρκυρα, Κως και Ηράκλειο)

 

Examples

 

THIS IS ______________AIRPORT INFORMATION ___

The first blank is for the name of the airport. Each time something in the recorded announcement changes, or at least once each hour, a new recording is made which is named after the next letter of the phonetic alphabet. (A, B, C etc)

WEATHER REPORT

The time followed by the word "hours"

WIND

Wind direction in degrees (always 3 digits) and speed in knots. If less than 5 KTS: "CALM"

VISIBILITY

If more than 10 km: Always given as: " one zero kilometres"

From 5 km to 10 km in kilometres

From 0 to 5 km in metres by 100m minor unit.

If more than 10 km and no cloud lower than 5000 feet and no rain or storm given as: "CAVOK" (Kav-o-kay, meaning: ceiling and visibility ok)

(RAIN, FOG, SNOW, HAZE etc)

Any Meteorological phenomenon occurring

CLOUD

 

 

 

 

 

 

 

 

 

If visibility less than 10 km and no clouds under 5000 feet: "SKY CLEAR"

If clouds are covering up to 2/8 of the sky: "FEW…" followed by the altitude where they are present.

If clouds are covering from 3/8 to 5/8 (included) of the sky: "scattered…." followed by the altitude they are present

If clouds are covering from 6/8 to 7/8 (included) of the sky: "BROKEN…" followed by the altitude that they are present.

If clouds are covering the whole sky (8/8) "overcast…" followed by the altitude that they are present.

If CBs (cumulonimbus) are present they are mentioned separately followed by the altitude, the bearing from the airport and the distance in kilometres

If TC (Towering cumulus) are present this is to be relayed

TEMPERATURE

In centigrade (Degrees Celsius)

QNH

In Hectopascals and inches (Hg)

Transition Level

It depends on the QNH

Runway in Use

  

RWY CONDITIONS

AND OTHER INFORMATION

Anything that helps the crews obtain a clear picture of the prevailing conditions regarding the Runway (Braking Action if necessary RVR etc), Taxiways, Navigational aids, vehicle or personnel movements, issued NOTAMs in effect etc.

Examples

This is Rhodos Airport information:

A

B

C

D

WEATHER REPORT

06:00

06:30

07:00

07:30

WIND

CALM

250o 14 kts

120o 15 KTS

090o 20 KTS

VISIBILTY

  

9 km

4000 M

8 KM

(RAIN, FOG, SNOW, HAZE etc)

    

RAIN

RAIN

CLOUD

CAVOK

FEW 020

FEW 020

SCT 040

OVC 080

SCT TC 015

BKN 030

OVC 080

CB 015 feet north 15km

TEMPERATURE

26

24

14

16

QNH

1013 HPA, 29,91 INCHES

1015 HPA,

29,97 INCHES

999 HPA,

29,50 INCHES

994 HPA,

29,38 INCHES

TRANSITION LEVEL

75

70

75

80

RUNWAY IN USE

25

25

07

07

RWY CONDITIONS

AND OTHER INFORMATION

RDS DME U/S

  

RUNWAY WET

Breaking action good.

TAXIWAY A CLOSED

 

A. This is Rhodos Airport information Alpha, weather report zero six zero zero hours. Wind calm, Cavok, Temperature two six, QNH ONE ZERO ONE SIX HECTOPASCALS, TWO NINER decimal NINER ONE INCHES. Transition Level SEVEN FIVE, Runway in use TWO FIVE. Rhodos DME Unserviceable.
B. This is Rhodos Airport information Bravo, weather report ZERO SIX TREE, ZERO hours. Wind TWO FIVE ZERO Degrees, ONE FOUR KNOTS. Visibility niner Kilometers, cloud FEW TWO TOUSAND FEET, temperature TWO FOUR, QNH ONE ZERO ONE FIVE HECTOPASCALS, TWO NINER DECIMAL NINER SEVEN INCHES. Transition Level SEVEN ZERO, Runway in use TWO FIVE.
C. This is Rhodos Airport information Charlie, weather report ZERO SEVEN ZERO ZERO HOURS. Wind ONE TWO ZERO Degrees ONE FIVE KNOTS. Visibility FOUR TOUSAND METERS, RAIN. Cloud FEW TWO TOUSAND FEET, SCATTERED FOUR TOUSAND FEET and OVERCAST EIGHT TOUSAND FEET. Temperature ONE FOUR, QNH NINER NINER NINER HECTOPASCALS, TWO NINER DECIMAL FIVE ZERO INCHES. Transition Level SEVEN FIVE, RUNWAY IN USE ZERO SEVEN. Runway WET, Breaking Action GOOD.

D. This is Rhodos Airport information Delta, weather report ZERO SEVEN TREE ZERO HOURS. Wind ZERO NINER ZERO Degrees TWO ZERO KNOTS. Visibility EIGHT KILOMETERS, RAIN. Cloud SCATTERED ONE TOUSAND FIVE HUNDRED FEET, TOWERING CUMULUS, BROKEN TREE TOUSAND FEET, OVERCAST EIGHT TOUSAND FEET. Charlie Bravo ONE TOUSAND FIVE HUNDRED FEET, NORTH ONE FIVE KILOMETRES. Temperature ONE SIX, QNH NINER NINER FOUR HECTOPASCALS, TWO NINER DECIMAL TREE EIGHT INCHES. Transition Level EIGHT ZERO, Runway in use ZERO SEVEN. TAXIWAY A closed.

Notes:
 If ATIS is not available all the information is given to arriving aircraft through the operational frequency. For departing aircraft requesting to start engines the following is given: Time, Runway in use wind, QNH, temperature, visibility for take off.
If aircraft is requesting weather information and the ATIS is operating normally the controller advises: "Monitor Atis frequency………" Notice the word "monitor" (ακρόαση – ακροαστείτε) and not: “contact”.
An ATIS transmission should not exceed 30 seconds if possible, but not at the clarity’s expense.
 If the wind direction varies more than 60o, the wind will be referred as "variable between…degrees and. ………Degrees".
If the wind’s velocity varies more than 10 knots from the mean value, it will be articulated by the term: "gusting maximum… Knots, minimum. …Knots".
After recording the Atis information it is essential to be played back for accuracy check before broadcasting on the air.
The status of the runway with regard to water presence may be defined:
a. Damp (Υγρός)

b. Wet (Βρεγμένος)

c. Water patches (Λιμνάζοντα νερά)

d. Flooded (Εκτεταμένα λιμνάζοντα νερά, πλημμυρισμένος).

Wind shear reports must be included intheATIS transmission  time of the occurrence and the type of aircraft.

2.2 RVR (Runway Visual Range)    Back to Index

When the visibility is less than 1500 m a RVR measurement is required. It represents the visible distance along the runway measured at the beginning (Touch down zone, A), the middle (Midpoint, B) and the end of the runway (Roll out, stop end, C) from a specific height from the tar mat. It is either measured by the appropriate apparatus or by an observer (Pilot, controller or specialized personnel).
If 0<RVR <50m it is given as: "RVR less than 50 m"
If 50m<RVR<150m it is given by minimum unit 25m (75m, 100m, 125m or 150m)
If 150m<RVR<800m it is given by minimum unit 50m (for example 200m, 650m etc)
If 800m<RVR<1500m it is given by minimum unit 100m (for example 900m, 1100m etc)

Example:

First part visibility 45m, second part visibility 80m and third part 840m.

Pilot:

Kos Tower, Olympic 735 request RVR RWY 33

Controller:

Olympic 735, Runway 33 wet, Alpha less than 50m, Bravo 75m, Charlie 800m

Pilot:

Alpha less than 50m, Bravo 75m, Charlie 800m, Olympic 735

2.3 Volmet                                        Back to Index

A continuous 24-hour transmission regarding weather information is also available on Volmet frequencies. Information provided here resembles the ATIS broadcast with the exception of the Runway in use and the addition of the DEW POINT (Σημείο Δρόσου). Athinai Volmet transmits on frequency 127,80 providing METAR and TREND for:

Athinai, Andravida, Thessaloniki, Rhodos, Iraklion, Kerkyra, Larnaka, Cairo and Istanbul.

 

2.4 Altimeter settings                       Back to Index

2.4.1 Standard ICAO atmosphere

If the altimeter is set at 1013,2 Hectopascals, the reading on the instrument represents Flight Level. It is always used above the transition Level in order to provide the same setting for all aircraft providing thus the needed separation. Height definitions and instructions should always be given in "Flight Level".

Example:

Controller:

Delta 450, climb to Flight Level 350, report leaving Flight Level 220

Pilot:

Climbing Flight level 350, leaving now Flight Level 220

 

2.4.2 QNH                                          Back to Index
If below the transition altitude all aircraft calibrate at the QNH of the area in order to read the altitude above sea level and have clear indication of how near terrain they are.

 

Example:

 

Controller:

SXAOZ Kos Tower climb 3000 feet on QNH 1015

Pilot:

Kos Tower, SXAOZ request QNH in inches

Controller:

SXAOZ QNH 29,97 inches

Pilot:

Climbing 3000 feet on 29,97 inches, SXAOZ

2.4.3 QFE                                           Back to Index

 
If the altimeter is set at the airports, QFE the reading of the instrument represents the height above the airfield. (Pilots rarely request it)

 Example:

Pilot:

Rhodos Tower, Kestrel 520 on final Runway 25

Controller:

Kestrel 520 cleared to land, wind 210o, 12 knots, QNH 1020

Pilot:

Cleared to land, Kestrel 520, request QFE

Controller:

QFE 1019

Pilot:

QFE 1019, Kestrel 520

 

2.5 Weather reports by pilots        Back to Index

2.5.1 Icing
In many occasions and during flight it is possible for ice to form on various surfaces of an aircraft resulting to dangerous situations due to change of aeronautical characteristics. It is the pilot’s obligation to report icing as soon as possible stating the Flight level or altitude it occurred and the severity of the phenomenon (light, moderate, severe). The controller must relay this information to other aircraft, if flying at the same level.

Example:

Pilot:

Makedonia Radar, Egypt Air 801 severe icing at FL 260

Controller:

Egypt Air 801, Makedonia Radar roger.

 

2.5.2 CAT (Clear Air Turbulence)        Back to Index
This phenomenon is very dangerous since it is not predictable and crews rely on each other in order to avoid it. Pilots are obliged to report CAT stating the severity of the incident (light, moderate, severe) and the Flight Level it occurred

 

 Example:

Pilot:                     Athinai Radar TWA 652, severe clear air turbulence at FL280

Controller:          TWA 652 Athinai roger.

 

Note: Irregular reports from pilots (mostly of US origin):

"We are experiencing some chops up here"

"It’s a little bumpy up here at FL 280, any reports of chops at FL 310?"

2.5.3 Spot wind                                     Back to Index
It is very important for Radar Area Controllers to know the exact direction and velocity of the wind at high Flight Levels in order to calculate correctly the time needed for aircraft to cover a given distance. The only way to obtain such information is to ask the pilots flying in the area of interest. The wind at a certain Flight Level is referred to as: "spot wind"

 Example:

Controller:

Lufthansa 932, Athinai Radar report spot wind at FL 390

Pilot:

Athinai Radar, the wind at FL 390 is 320 degrees, 95 knots

Controller:

Lufthansa 932, Athinai copied.

Note: The response might be: "Wind at 95 knots, diagonal 320" (This is not in

 compliance with ICAO phraseology).

2.5.4 Wind shear                                            Back to Index
This is another dangerous phenomenon whenever it occurs on final approach. Pilot’s report of Wind shear should be passed immediately to next acft attempting to land. This is the correct phraseology:
Controller: (Callsign), Caution, Wind shear reported by (Type of acft) at (altitude) (distance on final) Runway (Number).

2.6 Annex 10, (Volume II)                    Back to Index

Circumstances

Phraseology
* Denotes pilot transmission

1. Meteorological Conditions

Note: Wind is always expressed by giving the mean direction and speed and any significant variations.

a. WIND (number) DEGREES (number) (units)

b. WIND AT (height/altitude/flight level) (number) DEGREES (number) (units)

c. VISIBILITY (distance) [direction]

d. RUNWAY VISUAL RANGE (or RVR) [RUNWAY (number)] (distance)

e. PRESENT WEATHER (details)

f. CLOUD (amount, [type] and height of base) (or SKY CLEAR)

Note: CAVOK pronounced
CAV-0-KAY

g. CAVOK

h. TEMPERATURE [MINUS] (number) (and/or DEWPOINT [MINUS] (number))

 

i. QNH (number) [units]

j. MODERATE (or SEVERE) ICING (or TURBULENCE) [IN CLOUD] (area)

k. REPORT FLIGHT CONDITIONS

Unless responding to a request for turbulence or icing information

l.

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