Clarification of Sector Manning Principles

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Clarification of Sector Manning Principles

53RD ANNUAL CONFERENCE, Gran Canaria, Spain, 5-9 May 2014

WP No. 153

Clarification of Sector Manning Principles

Presented by PLC

Summary

The purpose of this paper is to analyse the existing manning (staffing) principles.

Introduction

1.1  IFATCA policy contains reference to two sector manning principles: Four Eyes Principle (4EP) and Single person operations (SPO).

1.2  Over recent years many factors, for example, unfavorable economic conditions, staff shortage and better technical support, have resulted in some ANSPs introducing different staffing principles other than those defined in the manual.

1.3  This need for IFATCA to look deeper into the different staffing scenarios became clear at the 52nd IFATCA conference in Bali in 2013, where there was some confusion as to what constituted 4EP, Single person operations (SPO), or other as yet undefined principles.

1.4  As a result, it was decided that new and existing sector manning principles should be examined, and definitions and policy produced or reviewed as appropriate.

1.5  The term ”sector” is used as a generic term, covering all types of ATM units, be it Centre, Approach or Tower.

Discussion

2.1  Various manning scenarios

There are many ways in which sectors are arranged around the globe. It is considered that the most common scenarios could be described as follows:

  • LPO
  • SPO
  • 2EP
  • 4EP
  • MSP

2.2  Definitions

2.2.1  Lone Person Operations (LPO)

No definition currently exists for this concept. The following definition is proposed:

LPO can be defined as operations where an ATCO is providing a service with no other person available on the unit, ATCO or otherwise.

2.2.2.  Single person operations (SPO)

There is an existing definition for SPO which states:

Single Person Operations (SPO) can be defined as operations where an operational ATC unit is providing service with only one appropriately qualified ATCO on duty.

 

In SPO another person may be present on the unit, but they are not qualified to operate that position, or to give breaks. PLC considers that this definition is valid and correct and as such no change is proposed.

2.2.3.  Two Eyes Principle

No definition currently exists for this concept. The following definition is proposed:

2EP can be defined as operations where an ATC unit provides service with one ATCO per sector, but with at least one more equally qualified ATCO on duty and available to assist or provide breaks.

2.2.4.  Four Eyes Principle

The existing definition on 4EP states:

4EP: Four Eyes Principle (4EP) can be defined as the situation where an active controller is accompanied by another appropriately qualified controller whose function includes that of a safety net by monitoring the same working area as the active controller.

 

PLC considers that this definition is essentially valid and correct, however for clarification the following change is proposed:

4EP: Four Eyes Principle (4EP) can be defined as the situation where an executive controller is accompanied by another appropriately qualified controller whose function includes that of a safety net by monitoring the same working area as the executive controller. The assisting controller is required to be qualified to assist the executive controller, but may not have the qualification to perform the executive controller role.

2.2.5 Multi sector planner (MSP)

No definition currently exists for this concept. The following definition is proposed:

MSP can be defined as the situations where two or more executive controllers working different sectors are assisted by another appropriately qualified controller. The assisting controller is required to be qualified to assist the executive controllers, but may not have the qualification to perform the executive controller role.

The role of the assisting controller may be referred to by different terms depending on the unit, for example as Planner or Co-ordinator.


2.3. Policy

2.3.1.  Lone Person Operations (LPO)

No policy currently exists for this concept. PLC however considers that LPO is an even less desirable situation than SPO. In case of incapacitation (due to health issues) or an emergency, an ATCO working LPO has no help whatsoever, which can have serious ramifications. Existing IFATCA policy on SPO (described in 2.3.2) should be amended to reflect that both SPO and LPO shall be avoided.

2.3.2.  Single person operations (SPO)

There is existing policy on SPO which states:

Single Person Operations (SPO) shall be avoided. In the unlikely event of unavoidable SPO, appropriate measures shall be taken to ensure that the SPO situation will be alleviated as soon as possible. Until such time, measures shall be taken to mitigate all impacts of SPO such as but not limited to: traffic regulation, work break provisions, informing neighbouring ATC units. Procedures shall be in place to implement such measures in an efficient way, not increasing the workload of the ATCO.

The use of single controller shifts should be strongly discouraged by MAs, both through their ANSP and their regulator.

When providers choose to do so, they must bear the responsibility for the resulting risk(s) to the system. An ATCO shall not be held liable for incidents or accidents resulting from an ANSP imposing the use of SPO.

 

PLC considers that this policy is valid and correct, however it should be amended to include both SPO and LPO as follows:

Single or Lone Person Operations (SPO/LPO) shall be avoided. In the unlikely event of unavoidable SPO/LPO, appropriate measures shall be taken to ensure that the SPO/LPO situation will be alleviated as soon as possible. Until such time, measures shall be taken to mitigate all impacts of SPO/LPO such as but not limited to: traffic regulation, work break provisions, informing neighbouring ATC units. Procedures shall be in place to implement such measures in an efficient way, not increasing the workload of the ATCO.

The use of SPO/LPO should be strongly discouraged by MAs, both through their ANSP and their regulator.

When providers choose to do so, they must bear the responsibility for the resulting risk(s) to the system. An ATCO shall not be held liable for incidents or accidents resulting from an ANSP imposing the use of SPO/LPO.

2.3.3.  Two Eyes Principle

No policy exists for this concept. It is recognised that 4EP is the preferred option to 2EP, since it offers redundancy and thus greater safety. However it was considered that policy on 2EP was not required.

2.3.4.  Four eyes principle

Existing policy on 4EP states:

Implementation of 4EP shall be strongly encouraged by MAs, both through ANSP(s) and regulator(s). An ATCO shall not be held liable for incidents or accidents resulting solely or in part from the non-implementation of the 4EP safety net.

 

PLC considers that this policy is valid and correct and as such no change is proposed.

2.3.5.  Multi sector planner (MSP)

No policy exists for this concept. It is considered that policy on MSP is not required.

Conventional concepts

3.1. Ideally, there are two controllers working together on the same sector. This is called 4EP, and is often encountered in terminal or en-route centres. However, for various reasons, some units chose to operate with just one controller. Depending on whether or not there is another equally qualified controller in the unit to relieve the one on the sector, one can talk about SPO/LPO (no backup controller available) or 2EP (one or more equally qualified controllers available).

3.1.1. Although IFATCA strongly encourages 4EP, 2EP has for various reasons become an accepted way of working at a large number of units. IFATCA believes that 2EP is still the less desirable option.


3.2. Multi-Sector Planner concept

3.2.1. The idea of having one planner for two or more different sectors is not new. Certain units have worked like this for many years. The concept has its benefits, as well as certain drawbacks. Those favouring the idea claim that with modern, advanced technologies, the concept is both feasible and efficient. The opponents, on the other hand, question the ability of a multi-sector planner to maintain a detailed traffic picture for more than one sector, especially during high workload. Furthermore, the removal of a designated planner from a sector raises the question of safety. In 4EP, the planner acts as a safety net – an extra pair of eyes provides better insight into traffic situation. Safety is at a very high level with two controllers dedicating their attention to conflict resolution and frequency monitoring. In an MSP scenario, the planner generally has a higher workload, and since his attention span is now divided, frequency monitoring becomes very difficult. MSP concept has recently been trialed in some countries, and Tactical controllers report that they do not feel comfortable with the loss of a dedicated planner controller.


3.3. Factors inducing staffing scenarios other than 4EP

3.3.1. There are numerous reasons for introducing temporary or permanent arrangements that are not 4EP. Generally, in the light of the global crisis and various pressures coming from different sources, ANSPs are constantly striving to secure high efficiency and productivity, while at the same time reducing costs as much as possible. One of the arguments in their favour nowadays is advanced technological equipment – various tools to better predict and prevent conflicts and manage traffic flows, as well as a high level of automation. However, it should be questioned whether these are acceptable reasons to change sector manning arrangements. Is technology reliable enough to rely on it fully and at all times? What happens if the system fails? It should be noted that, even with the support of advanced equipment, an ATCO can be quickly overwhelmed by an unforseen and unexpected event.


3.4. LPO and the Bournemouth incident

3.4.1.  LPO (often found in Tower units, especially during night shifts) is the least desirable of staffing arrangements. Having only one controller on a unit, with no- one else around (ATCO or otherwise), has proven to be perilous on more than one occasion.

3.4.2.  In February 1999, a lone tower controller was working nightshift at Bournemouth, UK airport (Glasgow Daily Record 25th February 1999). He decided to take a short break before the Euroscot flight from Edinburgh and the Palmair jet from Malaga arrived for landing. Unfortunately, he fell down the stairs and broke his ankle in three places. As he was lying in agony, the two flights approached and waited in vain for landing clearances. They started circling the airport, while the controller forced himself to crawl to a telephone and call the airport fire brigade. The fire crew arrived in a few minutes and contacted London control to tell them that the controller had been incapacitated. A relief controller was summoned and arrived at the unit to take over.

3.4.3. Luckily, the Bournemouth case resulted in no serious consequences. However, it is a vivid example of how things can go wrong in a matter of seconds, and with only one person on a unit, the ramifications can be severe.


3.5. SPO policy

3.5.1.  WP C.6.4 Review of Single Person Operations Policy and Four Eyes Principle (Bali 2013) stated:

“If a single controller is carrying out the roles of two people, for example working as an executive and planner controller, there is an increased risk that the attention needed by carrying out one task, may lead to the failure of detecting an error in the other task.

3.5.2.

Experience has shown that a lone ATCO can be quickly overwhelmed even with the most advanced equipment. In the span of an ATC career, a high proportion of ATCOs can expect to experience a rapid or unexpected rise in traffic, unforeseen weather, technical breakdowns, neighbouring ACC shutdowns or serious aircraft emergencies. These, or other circumstances, might significantly increase the workload and the complexity that an ATCO working under SPO or 2EP conditions will have to deal with.

3.5.3.

SPO or 2EP is seldom found in other high stress, highly demanding of safety- critical occupations. For example, commercial IFR air transport of passengers is regulated in most countries with a minimum flying crew of 2 pilots.

3.5.4.

As a general statement, it is an accepted fact that in a safety-critical working environment, redundancy in system components is an expected and welcome requirement. The redundancy of the human aspect in the system should also be considered as an essential requirement.

3.5.5.

When SPO is applied, there is no human “safety net””.

It is considered that these principles still apply equally today.


3.6. MSP versus the conventional principles

3.6.1.  The MSP concept has both advantages and disadvantages, when compared to other concepts. It is considered that it is generally better than 2EP, but still less favourable than 4EP.

3.6.2.  MSP enables the same number of sectors, but with less staff. Furthermore, it is convenient during relatively low traffic periods – two sectors can be combined into one, which would result in acceptable workload and thus enable controllers to keep their skill. Efficient planning would balance the traffic load on the sectors. However, during periods of higher workload, the absence of a dedicated planner could require the executive controller to carry out planner tasks which might distract from the core function of separating aircraft and reduce safety and redundancy, since a planner working on more than one sector could find it difficult to monitor the frequencies and the traffic situations on multiple sectors. For these reasons 4EP remains the most desirable manning arrangement when it comes to safety.

Conclusions

4.1.  Staff shortages, economic pressures, high levels of automation are some of the reasons for implementing practices other that 4EP. While less desirable, 2EP is already something ”normal” and widely used, and the MSP concept is also becoming more common. There are many undesirable human aspect effects when working other than 4EP: increased fatigue, false sense of safety, inadequate error detection, over-confidence… LPO has proven to be especially perilous, as things can always take a turn for the worse (controller incapacitation, emergency, and so on), and there is no human safety net.

4.2.  IFATCA strongly encourages the use of 4EP at all times.

Recommendations

5.1.  It is recommended that the following definitions be included in the manual:

LPO: operations where an ATCO is providing a service with no other person available on the unit, ATCO or otherwise.

2EP: operations where an ATC unit provides service with one ATCO per sector, but with at least one more equally qualified ATCO on duty and available to assist or provide breaks.

MSP: situations where two or more executive controllers working different sectors are assisted by another appropriately qualified controller. The assisting controller is required to be qualified to assist the executive controllers, but may not have the qualification to perform the executive controller role.

5.2.  It is recommended that the following definition:

4EP: Four Eyes Principle (4EP) can be defined as the situation where an active controller is accompanied by another appropriately qualified controller whose function includes that of a safety net by monitoring the same working area as the active controller.

Be changed to read:

4EP: Four Eyes Principle (4EP) can be defined as the situation where an executive controller is accompanied by another appropriately qualified controller whose function includes that of a safety net by monitoring the same working area as the executive controller. The assisting controller is required to be qualified to assist the executive controller, but may not have the qualification to perform the executive controller role.

5.3. It is recommended that IFATCA Policy:

Single Person Operations (SPO) shall be avoided. In the unlikely event of unavoidable SPO, appropriate measures shall be taken to ensure that the SPO situation will be alleviated as soon as possible. Until such time, measures shall be taken to mitigate all impacts of SPO such as but not limited to: traffic regulation, work break provisions, informing neighbouring ATC units. Procedures shall be in place to implement such measures in an efficient way, not increasing the workload of the ATCO.

The use of single controller shifts should be strongly discouraged by MAs, both through their ANSP and their regulator.

When providers choose to do so, they must bear the responsibility for the resulting risk(s) to the system. An ATCO shall not be held liable for incidents or accidents resulting from an ANSP imposing the use of SPO.

Be changed to read:

Single or Lone Person Operations (SPO/LPO) shall be avoided. In the unlikely event of unavoidable SPO/LPO, appropriate measures shall be taken to ensure that the SPO/LPO situation will be alleviated as soon as possible. Until such time, measures shall be taken to mitigate all impacts of SPO/LPO such as but not limited to: traffic regulation, work break provisions, informing neighbouring ATC units. Procedures shall be in place to implement such measures in an efficient way, not increasing the workload of the ATCO.

The use of SPO/LPO should be strongly discouraged by MAs, both through their ANSP and their regulator.

When providers choose to do so, they must bear the responsibility for the resulting risk(s) to the system. An ATCO shall not be held liable for incidents or accidents resulting from an ANSP imposing the use of SPO/LPO.

Last Update: September 30, 2020  

May 6, 2020   375   Jean-Francois Lepage    2014    

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