Weather Information — Page 104, Lesson 90

I want to walk you through the Weather Information chapter. This is a new topic, so let's start from the very beginning. Weather conditions are constantly changing, and as a professional pilot, you need to know what weather you're going to encounter during every phase of your flight. That knowledge is essential for safe operation. But because conditions change, we need a convenient system that supplies the latest information. And for that system to work globally, both the sources of weather information and the terms used must be understood by everyone, everywhere. Let's look at the sources available to you as a pilot in flight. There are three main sources: ATC, ATIS, and VOLMET. In every case, standard meteorological terms must be used. The information is transmitted slowly and enunciated clearly so that you and your crew can write it down as you hear it. First, you can request weather directly from Air Traffic Control. Here's a practical example. Imagine you're returning to Oxford from Cardiff, and you're receiving a radar service from Brize Radar. To decide how you'll approach Oxford, you could request the weather from Brize. Your call would sound like this: "Brize Radar, Oxford 94 request Oxford weather." The controller might reply: "Oxford 94, the Oxford 0950 weather, surface wind 360 degrees 5 knots, visibility 10 km, Nil weather, scattered 2500 feet. Runway 02 in use, QNH 1010." Notice that the time of the report is given — 0950 Zulu — and every element is spoken clearly: wind direction and speed, visibility in kilometres, any significant weather — here it's "Nil weather" meaning no significant weather — then cloud cover and height, the runway in use, and the QNH pressure setting. The second source is ATIS, which stands for Automatic Terminal Information Service. Its purpose is to reduce the workload on controllers. Instead of every pilot calling up to ask for the weather, a recorded message is transmitted continuously on a discrete VHF frequency or sometimes on a VOR frequency. As a pilot, you are expected to listen to that ATIS report before you contact the appropriate aerodrome controller. Every time the weather data changes, a new code letter is allocated — starting with Alpha, then Bravo, Charlie, and so on. Let me give you a typical example. Oxford has its own ATIS on frequency 121.950. A broadcast might sound like this: "Oxford Departure information Bravo at 0830 Zulu. Surface wind 210 degrees 10 knots. QNH 1019 QFE 1009. Brize Norton outside air temp 15 dewpoint 14. Call 121.950 for taxi and report QNH and information Bravo." So you hear the information code — Bravo — the time it was issued, the surface wind, the QNH and QFE pressure settings, the outside air temperature and dewpoint from a nearby station — Brize Norton in this case — and then a reminder to call the appropriate frequency and report that you have the current information. Now, that information code is critical. On your initial contact with the controller, you must state the information code you have received. That way, the controller knows exactly which version of the weather you have and can update you if the information has changed since that code was issued. For example, you would call: "Oxford Ground, GBODA with Information Bravo QNH 1019 request taxi." By saying "with Information Bravo," the controller knows you have the latest ATIS and doesn't need to read the full weather to you again. If a new code — say Charlie — had been issued since you listened, the controller would tell you to get the latest information. So to summarise: you have ATC as a direct source, ATIS as a continuous recorded broadcast on a dedicated frequency, and we'll cover VOLMET separately. In every case, the information is transmitted slowly and clearly using standard terms, and you must note the information code when using ATIS so you can report it on your first call.