The Tower provides Air Traffic Control in a radius of approximately 2 nautical miles, depending on circumstances. The Controller on duty, depending on the weather and traffic conditions, selects the Runway in use. Starting up engines though, occurs only under Air Traffic Control clearance. Without doubt, the number of aircraft near an Airport is larger than any other given airspace. Time allowed for reaction is minimized and even the smaller mistake on behalf of the controller in unforgivable.
Weather conditions bear exceptional significance and influence aviation work directly.
Visibility, surface wind, atmospheric pressure and runway braking action are significant information that should be passed on to the pilot before he attempts his approach or even start up engines. Regular physical exams are constituted to ensure this. Coordinating traffic in the vicinity of an aerodrome has many difficulties. The parameters are numerous. The basic principal is to keep aircraft separated during landings and take-offs.