Air Traffic Services, Aeronautical Information and Meteorology for Radiotelephony
Air traffic services, aeronautical information and meteorology for radiotelephony
This domain tests whether you know who you are talking to, what a clearance actually authorises, and how to read the weather and information material arriving by voice or data.
ATS units and services
ATC is provided by area control en route, approach control, and aerodrome (tower) control; ground control handles taxiing. Alongside ATC, air traffic services provide the flight information service and the alerting service. A clearance is valid only as issued and must be read back; a clearance limit is the point to which you may proceed pending further clearance.
Information
AIP, NOTAM and AIC carry aerodrome and en-route information. ATIS broadcasts the current aerodrome report on a discrete VHF frequency, updated under a letter code, so that first contact with tower becomes '...with information Charlie'. VOLMET broadcasts routine meteorological reports for en-route use.
Decoding weather
METAR: HKJK 121200Z 07012KT 9999 SCT020 BKN040 22/14 Q1018 NOSIG. Wind 070° at 12 kt, visibility 10 km or more, scattered cloud at 2,000 ft and broken at 4,000 ft above aerodrome level, temperature 22 °C, dewpoint 14 °C, QNH 1018 hPa, no significant change expected. SPECI is an unscheduled special report, TAF a forecast, SIGMET a warning of significant en-route hazards such as thunderstorms or volcanic ash.
Worked example
Tower passes 'wind 070 degrees 12 knots, runway 06, QNH 1018'. That direction is magnetic, because it is spoken in radiotelephony; the identical wind in the METAR above is true. This true/magnetic switch is the most common decoding error in the exam.
Traps
Reading 9999 as 9,999 metres; confusing QFE with QNH; assuming NOSIG cancels the TAF; omitting the ATIS letter on first call; treating a clearance limit as a landing clearance.