The limited field of view from the pilot's cockpit limits pilot's ability to avoid any close proximity to other air traffic around him during the course of the flight as well as on the ground. He is, therefore, dependent on the Air Traffic Controller for directing him in his flight and on the ground for all manoeuvres right till the end of his journey.
To eliminate confusion in understanding a particular instruction, standard Radio Phraseologies have been laid down which are understood by the pilots and Air Traffic Controllers the world over. A small mistake by Air Traffic controller or a misunderstanding by a pilot can result in a disaster and the loss of many lives. While pilots are required to follow Controller's instructions faithfully and meticulously, Air traffic Controller ensures that the instructions given are clear and flawless.
Air traffic Controllers are well trained professionals who design the sequencing of air traffic in the air space and along pre-determined routes of arrival and departure to and from airports around the world. They are responsible for the management of flow of safe, orderly and expeditious traffic with least possible delays on the ground as well as in the air. They are also responsible for providing advice and information useful for the safe and efficient conduct of flight and alerting appropriate organisations regarding aircraft in need of assistance, search and rescue.
A Controller is a quick thinking man who doesn't have the privilege to stall. He is like a surgeon, composed in knowledge, precise in actions yet without the benefit of burying his mistakes. All his instructions to aircraft are recorded continuously on tape and any instructional error is traceable by replay, a tremendous constraint on the individual - a disturbing yet necessary requirement that no other profession entails and no professional has to contend with. This makes the Controller a man with a mission of responsibility scrutinised constantly, functioning to standards of pinpoint accuracy. He plays a major role for continued safety in the field of aviation-the safety that we as a passenger enjoy!