Meteorological Information for Aircraft in Flight — Page 541, Lesson 521

I want to walk you through the meteorological information services available to you as a pilot once you're airborne. We're going to look at three key services: VOLMET broadcasts, the Automatic Terminal Information Service, or ATIS, and the general WX weather broadcast. Let's start with what you'd actually hear. Here is a sample of a real VOLMET broadcast, taken from London/Gatwick at 1120 Zulu time. The wind is reported as 190 degrees at 10 knots, and it's variable between 150 and 220 degrees. Visibility is 10 kilometres or more, and there are showers in the vicinity. The cloud report shows few cumulonimbus at 2,400 feet, and scattered cloud at 4,000 feet. Temperature is 11 degrees Celsius, dew point is 9 degrees, and the QNH is 999 hectopascals. Now compare that to London/Heathrow at the same time. Wind is 220 degrees at 12 knots, variable between 190 and 250 degrees. Visibility is again 10 kilometres or more, but here we have light rain showers. The cloud is few cumulonimbus at 2,500 feet, and broken at 11,000 feet. Temperature is 11, dew point 8, QNH 997. And then you see the word "TEMPO" — that means temporarily, the visibility is expected to drop to 4,500 feet with rain showers. So the TEMPO group tells you a temporary deterioration in conditions. Now, the VOLMET broadcasts I've just described are transmitted in the VHF band. But VOLMETs are also broadcast all over the world in the High Frequency band, typically between 3 and 20 megahertz. That's important because HF can cover much longer ranges than VHF, so you can receive these broadcasts when you're far from the airport, even over the ocean. Let me define the acronyms you'll see on the broadcast schedule. VOLMET stands for "Routine Broadcast of Meteorological Information for Aircraft In Flight" — there are two versions: INTL for international and NATL for national. ATIS stands for "Automatic Terminal Information Service." And WX is simply the abbreviation for "Weather Broadcast." Now look at the table in Figure 29.2. This is the schedule of HF VOLMET broadcasts for the Europe region, labelled EUR-MET. Each row gives you the frequency in megahertz, the type of broadcast — whether it's VOLMET, ATIS, or WX — the broadcast times in minutes past the hour, the call sign, the state, the station name, its latitude and longitude, and any remarks. For example, on 3.413 megahertz, you have a VOLMET broadcast at 00 and 30 minutes past the hour, call sign EIP, from Shannon, Ireland, at 52 degrees 34 minutes north, 09 degrees 12 minutes west, and it's only active from 1800 to 0530 Zulu. On 4.645 megahertz, you have a continuous ATIS broadcast from Tallinn, Estonia, call sign ES.., at 59 degrees 25 minutes north, 24 degrees 50 minutes east, with a remark "ex-RPH 6" — that's a note about a previous frequency or call sign. On 4.742 megahertz, you have a WX broadcast at 00 and 30 minutes past the hour from Brize Norton in the UK, call sign MLP. And on 5.450 megahertz, you have a VOLMET broadcast at 00 and 30 from West Drayton, which is London RAF, call sign MPL 2. Notice some frequencies are listed as "unassigned" — for example, 2.998 and 6.580 megahertz. Those are reserved for VOLMET but not currently in use. And some entries have incomplete information, like the one at 6.580 where the station name is just "n (London) 'RAF'" — that's likely a formatting issue in the source, but the principle is the same: you have a frequency, a type, and a station. So as a pilot, you need to know which frequencies to select for the area you're flying through, what time the broadcast starts, and what type of information it provides — whether it's a full VOLMET with multiple airports, a dedicated ATIS for one airport, or a general weather broadcast. This table is your reference for that.