Air Information Publications — Page 10, Lesson 17

I want to walk you through the Air Information Publications chapter, starting with a critical operational tool you’ll use every time you fly into a busy airfield: the Automatic Terminal Information Service, or ATIS. At busy airfields, the radio-telephony (RTF) channels used for talking to air traffic control can get very congested. To reduce that loading on the operational channels, ATIS broadcast messages are used. These are recorded or continuously repeated messages that pass routine arrival and departure information on a discrete RTF frequency — a separate frequency dedicated just to that broadcast — or, in some cases, on an appropriate VOR frequency. Now, as a pilot of an aircraft inbound to one of these airports, you are required, on first contact with the aerodrome Air Traffic Services (ATS) Unit, to acknowledge receipt of the current ATIS information. You do this by quoting the code letter of the broadcast. That code letter is a single letter — A, B, C, and so on — that changes each time the broadcast is updated. So when you call the tower, you say something like “with information Bravo” to confirm you have the latest details. For outbound aircraft — those departing — you are not normally required to acknowledge receipt of the departure ATIS. However, you are requested to ensure that you are in possession of up-to-date information before you start moving. The book also points you to ICAO Doc 7030 for further information on ATIS. Let me give you a typical example of an ATIS broadcast, taken from Oxford/Kidlington. I’ll read it as you might hear it: “ATIS B: Runway 02 right hand; Helicopter Area 1 Left; Surface W/V 330/10; QNH 1018, QFE 1008; Temperature -1°C, Dewpoint -3°C. Contact tower on 121.95 MHz.” So, what does each part mean? The letter B is the current information code. Runway 02 right hand tells you which runway is in use and the circuit direction. Helicopter Area 1 Left identifies a specific area for helicopter operations. Surface W/V 330/10 means the surface wind is from 330 degrees true at 10 knots. QNH 1018 is the pressure setting to give you altitude above mean sea level; QFE 1008 is the pressure setting to give you height above the aerodrome. Temperature is minus 1 degree Celsius, and the dewpoint is minus 3 degrees Celsius. Finally, it tells you which frequency to contact the tower on: 121.95 MHz. Now, the chapter moves into meteorological information. Under AIP GEN — that’s the General section of the Aeronautical Information Publication — we have Meteorological Charts. National Meteorological Offices routinely issue written forecasts of selected areas at fixed times daily. For the UK, these are on Forms F214 and F215. The UK Met Office also issues European and North Atlantic forecasts. Details of areas of coverage, times of issue, and periods of validity are all given in the UK AIP. Next, we have Meteorological Information. Several types of weather reports and forecasts are broadcast by teleprinter and/or radio throughout the UK and internationally in text form. These include: - Aviation Routine Weather Reports, called METAR or Actuals — these are the actual observed weather at an aerodrome. - Aerodrome Forecasts, called TAF — these are forecasts for a specific aerodrome. - SIGMET — information concerning en route weather phenomena which may affect the safety of aircraft operations. This includes volcanic activity. - Selected special weather reports, called SPECI — these are special reports issued when weather conditions change significantly between routine reports. The Meteorological Watch Offices, or MWOs, are responsible for preparing and disseminating SIGMETs to the appropriate Area Control Centre (ACC) or Flight Information Centre (FIC) within their own and agreed adjacent Flight Information Regions (FIRs). Aircraft in flight should be warned of the occurrence or expected occurrence of a SIGMET phenomenon for the route ahead for up to 500 nautical miles or 2 hours flying time — whichever comes first. The book lists examples of SIGMET phenomena. At subsonic levels, these include: freezing rain, severe mountain wave, and volcanic ash cloud. At transonic and supersonic levels — that’s Flight Level 250 to 600 — the examples are: hail, volcanic ash cloud, and moderate or severe turbulence. Information to aircraft in flight is usually supplied in accordance with area Meteorological Watch procedures, supplemented when necessary by an En Route Forecast Service. Information is also available from the appropriate ATS Unit at the commander’s request, or from meteorological broadcasts. Finally, aircraft can obtain aerodrome weather information from any of the following sources: VOLMET broadcasts — which are continuous broadcasts of aerodrome weather reports on specific frequencies, and you can see a table in Figure 1.3 for those; ATIS broadcasts, which we already covered; or by request to an ATS Unit, but whenever possible only if the information required is not already available from a broadcast. The principle is to use the automated broadcast first to keep the radio channels free for more urgent communications.