The Controller/Pilot Relationship 
--  "the awkward alliance"

1. Air Traffic in WA

2. ATC in Australia

3.Geography and Weather in WA

4. Airspace Management over WA

5. The Perth Traffic Management Plan

6. Flow Control and Sequencing

7. Military Operations

8. Working at West Radar

9. ATC Training

10. The Controller/Pilot Relationship

This page is based on a chapter in my M.Ed. dissertation ( a link is on the home page).

The Air Traffic Controller's Task
The air traffic controller plays a central role in the safety of the air traffic system.  Amongst other responsibilities, the controller reduces the pilot’s workload by taking over the role of detecting and resolving conflicts with other aircraft operating in the same or adjacent airspace, and by providing warnings and advice of known weather hazards and possible military airspace infringements.

The goal of the air traffic system is to accomplish “the safe, efficient conduct of aircraft flights” and “to maintain a safe, orderly and expeditious flow of air traffic”.

Air traffic controllers, with their common language, are the crucial link in international aviation.  The seamless flight of air traffic across international borders and through jealously guarded sovereign airspace of, often, mutually antagonistic nations would not be possible without the co-ordination of controllers.  Whether nationally or internationally, the joint goals of safety and efficiency are accomplished through an intricate series of procedures, judgments, plans, decisions, communications and coordinating activities.  The public is familiar with the radio communications which occur between pilots and controllers but equally as critical are the coordinations within and between air traffic control facilities when controllers ‘hand-off’ aircraft as they pass from one controller’s sector of responsibility to another.  The predominate factor of the ATC system is that it is centered on the controller with all the safety critical decisions emanating from that source.  This figure illustrates the central role of the controller:

There are several distinguishing features to air traffic control:

·      Three-dimensional nature of movement:  The three-dimensional nature of aircraft trajectories can only be displayed on a two-dimensional radar screen or, more awkwardly, on a two-dimensional procedural display console.  The controller must think in three-dimensions and predict a fourth.

·      Speed and stress:  Mastering the three-dimensional movement is further complicated by the speed at which it occurs.  This reduces the time to recognise, evaluate and react to unexpected problems.  It is a matter of reaching quick, workable decisions and not of looking for a perfect solution but finding it too late.  Often heuristic thinking is required, not algorithmic.

·      Limited correction possibilities:  There is little leeway for correction.  Safety tolerances are usually large but the rapid sequence of events reduces the time remaining to register or correct errors.  Controllers must be able to concentrate and react rapidly.

·      Great significance of small errors:  Minor errors or slips can cause serious accidents yet these are difficult to detect.  Human error has been called “the relentless threat to aviation safety” (Maurino, Reason, Johnston and Lee, 1995).

·      Constant changes:  The aviation system is in the vanguard of technical development.  ATC procedures are in a state of virtually constant change which must be assimilated.  Constant retraining, changes to procedures, equipment and aircraft types and performance characteristics require controllers to constantly adapt and be mentally flexible or be overtaken by change.

The Pilot's Task
The role of the pilot in the exchange of verbal information differs from that of the controller and is succinctly established in the Civil Aviation Regulation (CAR) 100: 

  (1)  An aircraft shall comply with air traffic control instructions.

  (4)  The pilot in command of an aircraft is responsible   for compliance with air traffic control clearances and air traffic control instructions.                                                                    (Civil Aviation Safety Authority, 1998)   

The pilot’s task then, except in an emergency, is to receive advisory information, accept instructions, and to act upon them.  The pilot must trust a controller’s commands because he or she is not, in general, in receipt of enough information regarding the traffic disposition to question them.  The pilot provides an element of redundancy by reading back certain instructions, such as clearances, but otherwise provides little information unless first asked for it.

The Controller/Pilot Relationship - the awkward alliance
Bert Ruitenberg (1995) has contrasted the work of pilots and controllers.  Although trained to deal with many potentialities, pilots in their normal work ideally should encounter no problems.  But the routine work of a controller almost exclusively exists of problem solving, in trying to accommodate traffic safely, efficiently and in an orderly manner in the available airspace.  

Pilots and controllers have differing perspectives of the conflicting pressures of safety and efficiency:  

• Firstly, a controller has several aircraft to deal with whereas a pilot is concerned with one.  The pilot wants to fly the aircraft in the most efficient manner by choosing direct routes or those with the most favourable winds and optimal altitudes.  This is not always compatible with the controller’s problem of safely managing numerous climbing, descending and crossing aircraft spread throughout a large airspace volume but converging and congregating at a few airports or navigation aids.  

• Secondly, the controller’s perspective of efficiency differs because his or her goal is to maintain an evenly spaced flow of all aircraft from airport to airport, even if this means slowing, holding or ‘track stretching’ aircraft to delay their arrival.  The aircraft crew are under pressure to deliver their passengers on time and to ensure that the aircraft is available for its next scheduled flight.  The controller tries to maintain sensitivity to the crew’s need to avoid excessive and abrupt maneuvering (for passenger comfort) while achieving safe separation with other aircraft and efficient sequencing. 

Besco (1997) has labeled the controller/pilot relationship the “awkward alliance”.  There are numerous causes for tension, such as the role of the controller as ‘traffic cop’, the propensity for pilots to bend the truth on time estimates and weather conditions to gain a higher priority and track shortening, and due to perceived status and salary differences.  The relationship is unique, he states, because it is not based on emotional attachments nor on political commitments nor organisational pressures. The pilots’ convictions of positive expectations are based upon repeated successes of consistent, successful and dependable performance.  On any flight, a pilot deals with a dozen or more controllers, none of whom are known personally, and, similarly, a controller deals with dozens of pilots.  In order for the system to work, exchanges must be calm and professional.  Controllers supply the support that has enabled all skill levels of pilots flying all types of aircraft to safely complete all types of flight plans through airspace and to airports of all complexity levels in all types of weather.  Pilots, because they have an incomplete knowledge of the air traffic situation, literally put their own lives and the lives of their passengers in the hands of controllers.  They place a heavy reliance on the voices of the air traffic control system. 

The teamwork reflected in communication between pilots and controllers is a critical component of the air traffic system because it provides the system’s flexibility.  Most controllers are not pilots and most pilots are not controllers.  Instead of just having impersonal radio contact, it has proved worthwhile for pilots and controllers to observe each other at work.  The more they learn about each other, the easier it is to recognise and discuss common interests.  Many problems of communications stem from the lack of knowledge the parties have about each other.  The closure of many regional control towers, flight service units and briefing offices during the past two decades has markedly reduced the face-to-face contact between pilots and air traffic service personnel.