...Finding out what's the runway, what's the weather, etc...
OBJECTIVES:
- Explain ATIS information
- Items listed in what order and how to decode?
ATIS stands for Automatic Terminal Information Service.
Before departing from or arriving at an airport, pilots want to have the latest operational airport information (runway-in-use, closed taxiways,...) and the newest weather update (wind direction and speed, cloudbase,...). To avoid that the ATC frequency would become congested by pilots who request this information, it is made available via the Automatic Terminal Information Service (ATIS).
In real-life, at the airports where it is installed, the ATIS is continuously broadcasted over a separate VHF radio frequency or on the voice portion of a local NAVIGATION AID such as a VOR.
Area Control Centers (ACC, in VATSim CTR), Upper Area Control Centers (UAC) and Military controlled airfields have no ATIS.
On VATSim, ATIS "transmissions" are displayed in the IvAp interface each time initial contact is made on another ATC channel.
What does ATIS tell us?
On VATSim, the order in which ATIS information is shown differs from real-life because of the limited space that is available in the IvAp interface. Operational information is displayed at end of the ATIS so there is no need to scroll with the line select keys when it contains a lot of information.
In general ATIS information includes:
- name of aerodrome;
- arrival and/or departure indicator;
- designator;
- time of observation, if appropriate;
- surface wind direction and speed, including significant variations;
- visibility and, when applicable, RVR; *(see note)
- present weather; *(see note)
- clouds below 1.500 m (5000 ft) or below the highest minimum sector altitude (MSA), whichever is greater; cumulonimbus (Cb); if the sky is obscured, vertical visibility when available;*
- air temperature;
- dew point temperature;
- altimeter setting(s);
- any available information on significant meteorological phenomena in the approach and climb-out areas including wind shear, and information on recent weather of operational significance;
- trend forecast, when available;
- type of approach(es) to be expected;
- the runway(s) in use;
- significant runway surface conditions and, if appropriate, braking action;
- holding delay, if appropriate;
- transition level, if applicable;
- other essential operational information;
and
- specific ATIS instructions.
* These elements are replaced by the term “CAVOK” when:
-
- the visibility is 10 km or more, and
- no significant weather, and
- no clouds below 1.500 m (5000 ft) or below the highest minimum sector altitude (MSA), whichever is greater, and
- no cumulonimbus (Cb)
Example:
"Aquitaine Approche information DELTA recorded at 0915z
LFBD 070900Z 28005KT 9999 FEW030 BKN039 09/03 Q1021 NOSIG
ARR RWY 23 / DEP RWY 23 / TRL FL050 / TA 5000FT
ILS23 110.30/Crs 228
CONFIRM ATIS INFO DELTA on initial contact".
Pilots can receive the continuous ATIS broadcast at times when cockpit duties are least pressing and listen to as many repeats as desired.
ATIS broadcasts shall be updated each time a new routine weather report or special weather report is issued and also when there is a change in other important data such as runway change, instrument approach in use, etc.
How to make sure the latest information is received?
Pilots should obtain the ATIS information, whenever ATIS is in operation.
The current ATIS message is identified by a letter and is valid until a significant change has to be made (new runway in use, weather deterioration or improvement, facility failure).
The first ATIS of the day is usually identified as "Information Alpha" (see "Letters Codes" for details about letters codification).
The second ATIS message will be "Information Bravo".
Then Information Charlie, Delta etc... when reaching Zulu, the next will be Alpha again.
On initial contact, pilots should inform controllers that they received the latest ATIS information by repeating the letter of the alphabet of the ATIS, like "Information Sierra".
Controllers will pass important information to pilots who do not acknowledged the letter of the ATIS or received ATIS information that is no longer correct.