ATIS broadcast, code letter, contents and when to obtain it

ATIS: continuous recorded broadcast on a discrete VHF/UHF frequency, at aerodromes with an operational ATIS.

• Carries latest METAR/SPECI, except RVR (TC AIM MET 1.1.5).
• Relieves frequency congestion: broadcasts routine info ATC would otherwise repeat to every arriving and departing aircraft (TC AIM RAC 1.3).
• Recording, not a briefing: call a staffed FIC for a briefing.

Get it before calling:

• Obtain before contacting ground control or tower, if available (TC AIM RAC 4.2.1).
• Arrivals must monitor it for basic aerodrome info before contacting tower (TC AIM RAC 4.4).

Code letter (TC AIM RAC 1.3; TP 1102, Radio Communication: ATIS):

• Starts at ALFA.
• Advances through phonetic alphabet when content changes.

Contents (TC AIM RAC 1.3):

• Airport name and code letter
• Weather: time, wind including gusts, visibility, weather/obstructions to vision, ceiling, sky condition, temperature, dew point, altimeter, pertinent SIGMETs/AIRMETs/PIREPs
• Type of instrument approach in use
• Landing runway (IFR and VFR)
• Departure runway (IFR and VFR)
• Relevant NOTAM excerpts, NAVAID serviceability, or field conditions
• As applicable: notice of restriction or suspension of landings or takeoffs (e.g. RVOP/LVOP, airport operator direction, obstructed runway protected area). When conditions change rapidly, ATC may issue it directly instead of through ATIS (TC AIM RAC 1.6.1.1(a)).

Never carries (TC AIM RAC 1.3):

• Current time
• RVR (runway visual range) measurements

Temperature and dew point come only from scheduled hourly weather observations, not a live sensor feed (TC AIM RAC 1.3).

NOTAM and field-condition items may be dropped after being broadcast for (TC AIM RAC 1.3):

Rapidly changing weather or airport conditions (TC AIM RAC 1.3):

• Routine ATIS replaced by: "Because of rapidly changing weather/airport conditions, contact ATC/FSS for current information"

Trap: ATIS gives no current time or RVR, and its temperature/dew point are only as fresh as the last hourly observation.

Practice