Core skills of a controller

Air traffic controllers are generally individuals who are well organized, are quick with numeric computations and mathematics, have assertive and firm decision making skills, and possess excellent short-term memory and visual memory abilities. In addition, studies have shown that air traffic controllers generally have a degree of situational awareness that is much higher than the average population.[citation needed] Excellent hearing and speaking skills are a requirement, and trainees undergo rigid physical and psychological testing. In addition they are generally assertive but calm under pressure, and they are able to follow and apply rules yet be flexible when necessary. Air traffic controllers must maintain some of the strictest medical and mental requirements for professions; conditions such as diabetes, epilepsy, heart disease, and many mental disorders (e.g., bipolar disorder, a history of drug abuse) typically disqualify people from obtaining certification. Conditions such as hypertension, while not disqualifying, are taken seriously and must be monitored with medical examinations by certified doctors. Controllers must take precautions to remain healthy and avoid certain medications that are banned for them. Many drugs approved by the U.S. Food and Drug Administration (FDA) such as SSRI antidepressants are banned without specialized certification. Almost universally, trainee controllers begin work in their twenties and retire in their fifties.
Communication is a vital part of the job: controllers are trained to precisely focus on the exact words pilots and other controllers speak, because a single misunderstanding about an altitude level or runway number for example can have tragic consequences. Controllers communicate with the pilots of aircraft using a push-to-talk radiotelephony system, which has many attendant issues such as the fact only one transmission can be made on a frequency at a time, or transmissions will either merge together or block each other and become unreadable.
Although local languages are sometimes used in ATC communications, the default language of aviation worldwide is English. Controllers who do not speak this as a first language are generally expected to show a certain minimum level of competency with the language.
Teamwork plays a major role in a controller’s job, not only with other controllers and air traffic staff, but with pilots, engineers and managers.

Area or en route

Area controllers are responsible for the safety of aircraft at higher altitudes, in the en route phase of their flight. In most nations they are known as "area" or "en route" controllers. Airspace under the control of Area controllers is split into sectors which are 3D blocks of airspace of defined dimensions. Each sector will be managed by at least one Area controller. This can be done either with or without the use of radar: radar allows a sector to handle much more traffic, however procedural control is used in many areas where traffic levels do not justify radar or the installation of radar is not feasible. In the United States, En-Route controllers work at Air Route Traffic Control Centers or ARTCCs. In other countries, area controllers work in Area Control Centers, controlling high-level en-route aircraft, or Terminal Control Centers, controlling aircraft at medium levels climbing and descending from major groups of the airports.

Aerodrome or Tower

Aerodrome or Tower controllers control aircraft within the immediate vicinity of the airport and use visual observation from the airport tower. The tower's airspace is often a 5-nautical-mile (9.3 km) radius around the airport, but can vary greatly in size and shape depending on traffic configuration and volume.
The tower positions are typically split into many different positions such as Flight Data/Clearance Delivery, Ground Control, and Local Control (known as Tower by the pilots); at busier facilities, a limited radar approach control position may be needed.
The roles of the positions are;

• Flight Data/Clearance Delivery: issues IFR flight plan clearances, usually prior to taxi. Unlike the other positions, FD/CD only involves departing aircraft.
• Ground: issues taxi instructions and authorizes aircraft/vehicle movements on the airport except the active runway(s); controllers are not responsible for aircraft movement on ramps or other designated non-movement areas.
• Local (Tower): issues takeoff and landing instructions/clearances and authorizes aircraft/vehicle movements on or across runways.
• Approach: issues instructions to aircraft who are intending to land at the airport. This involves vectoring aircraft in a safe, orderly, and expeditious manner and, if needed, stacking the aircraft at different holding altitudes.

Civilian/military - public/private

Most countries' armed forces employ air traffic controllers, often in most if not all branches of the forces. Although actual terms vary from country to country, controllers are usually enlisted.
In some countries, such as Brazil, all air traffic control is performed by the military.[2] In other countries, military controllers are responsible solely for military airspace and airbases; civilian controllers maintain airspace for civilian traffic and civilian airports. Historically in most countries this was part of the government and controllers were civil servants. However, many countries have partly or wholly privatized their air traffic control systems; others are looking to do the same.

Education

Civilian Air Traffic Controllers' licensing is standardized by international agreement through ICAO. Many countries have Air Traffic Control schools, academies or colleges, often operated by the incumbent provider of air traffic services in that country, but sometimes privately. These train student controllers from walking in off the street to the standards required to hold an Air Traffic Control license, which will contain one or more Ratings. These are sub-qualifications denoting the air traffic control discipline or disciplines in which the person has been trained. ICAO defines five such ratings: Area (procedural), Area Radar, Approach (procedural), Approach Radar and Aerodrome. In the United States, controllers may train in several similar specialties: Tower, Ground-Controlled Approach (GCA), Terminal Radar Control, or Enroute Control (both radar and non-radar). This phase of training takes between 6 months and several years.
Whenever an air traffic controller is posted to a new unit or starts work on a new sector within a particular unit, they must undergo a period of training regarding the procedures peculiar to that particular unit and/or sector. The majority of this training is done in a live position controlling real aircraft and is termed On the Job Training (OJT), with a fully qualified and trained mentor or On the Job Training Instructor (OJTI) also 'plugged in' to the sector to give guidance and ready to take over in a second should it become necessary. The length of this phase of training varies from a matter of months to years, depending on the complexity of the sector.
Only once a person has passed all these training stages they will be allowed to control on their possessions.

Work patterns

Typically, controllers work "on position" for 90 to 120 minutes then they get 30 minutes break. Except at quieter airports, Air Traffic Control is a 24 hours, 365-days-a-year job. Therefore controllers usually work rotating shifts, including nights, weekends and public holidays. These are usually set twenty eight days in advance. In many countries the structure of controllers' shift patterns is regulated to allow for adequate time off. In the UK the most common pattern is two mornings, two late afternoons and 2 evenings/nights followed by 4 day break.

Age restrictions

If employed by the FAA, the latest one can start training is usually age 30, and retirement is mandatory at 56 years of age. However, retired military air traffic controllers may qualify for appointment after reaching 31 years of age.
With NATS, the minimum age to start the application and training is 18 while the mandatory retirement age is 60. If an 18 year old joins and is successful then they will have to be posted to an Area course which will ensure they are 21 years old on graduation, thus old enough to hold a radar licence.

Stress

Many countries regulate work hours to ensure that controllers are able to remain focused and effective. Research has shown that when controllers remain ‘in position’ for more than two hours without a break, performance can deteriorate rapidly, even at low traffic levels. Many national regulations therefore require breaks at least every two hours. However psychophysiological research in the United States has not supported the widespread perception that air traffic control is an unusually stressful occupation (Smith, 1980, 1985). Melton (1982) summarized the research findings in the US: "Thus, it is clearly inappropriate from the psychological perspective to describe ATC work, as is commonly done in the popular press, as an unusually stressful occupation. Popularized accounts of controller stress deal with the exceptional rather than the typical controller or facility." Additionally, regulations govern shift length, number of night shifts done consecutively, length of time off required between shifts, etc. A typical work week for a controller is an 8 hour day, 5 days per week.

Computerization and the future

Despite years of effort and the billions of dollars that have been spent on computer software designed to assist air traffic control, success has been largely limited to improving the tools at the disposal of the controllers such as computer-enhanced radar. It is likely that in the next few decades, future technology will make the controller more of system manager overseeing decisions made by automated systems and manually intervening to resolve situations not handled well by the computers, rather than being automated out of existence altogether.
However there are problems envisaged with technology that normally takes the controller out of the decision loop but requires the controller to step back in to control exceptional situations: air traffic control is a skill that has to be kept current by regular practice. This in itself may prove to be the largest stumbling block to the introduction of highly automated air traffic control systems