Text 3 the effects of the weather on aviation
Except perhaps for local or very short flights, a pilot, before taking off, obtains a weather forecast giving him the weather conditions which are expected along the route of his flight and at his destination. Because weather conditions affect aircraft in flight, to a considerable extent, special aviation forecasts are provided by meteorologists at weather offices all over the world.
The meteorologist, or forecaster, prepares a weather chart which shows the current weather conditions over the whole country. The current weather chart is called a synoptic chart. This synoptic chart shows the areas of low pressure, the areas of high pressure, where precipitation is falling, and all other weather conditions across the country.
From this weather map, the forecaster can advise pilots of the weather conditions they can expect to encounter during their flights. A high pressure area, for instance usually means good weather while a low pressure area usually involves one or more fronts producing clouds and precipitation over many hundreds of miles.
A pilot needs to know the wind direction and speed. A headwind will obviously delay the arrival of flights and is to be avoided if at all possible. A tailwind on the other hand, can be of great advantage as it increases the ground speed and results in a reduction in fuel consumption. Winds vary with altitude, and also from one place to another, so information on winds is very important.
Pilots will pay particular attention to a low pressure area which lies en route, and the weather conditions associated with that low pressure area. The associated cold or warm fronts could involve clouds, thunderstorm, snow, rain, and turbulence. From his charts, the meteorologist can forecast where this weather will be at a certain time in the future, and with the help of these predictions, the pilot will decide which route to fly and when and he will know what weather conditions to expect. Should the forecast be very bad, for example, dense fog or poor visibility due to snow, the pilot may decide to postpone his flight. A pilot flying VFR would also cancel his flight because of low ceiling or low overcast conditions en route.
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Text 4 the role of radar in atc
Ideally, pilots want an unrestricted climb to the most economic cruising level and then to maintain this level for as long as possible before starting a continuous descent right down to the runway.
The approach controller will be concerned with using the radar to expedite departing aircraft with an initial climb and separating them from the arrivals. At the same time the controller will be establishing an arrival sequence, to achieve maximum runway utilisation, with a variety of aircraft types having different speeds on the approach.
Radar is used primarily to expedite the flow of air traffic whilst maintaining safety.
Radar separation between identified aircraft is 5NM compared to 10 minutes (or up to 80NM) when using non-radar separation on the same track at the same level. The controller is now handling a great many more aircraft in the airspace and more aircraft are able to fly at their preferred flight levels.
Whilst under radar control and particularly when an aircraft is on a radar vector, the controller effectively takes over the navigation of the aircraft and will be responsible for preventing the aircraft from crashing into the ground.
The en-route, or area controller, will be endeavoring to climb departing aircraft to their requested cruising level and descend arriving aircraft from their high level cruise to a lower level for the approach to an aerodrome.
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