Environment – Study Environment Case

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Environment – Study Environment Case

50TH ANNUAL CONFERENCE, Amman, Jordan, 11-15 April 2011

WP No. 87

Environment – Study Environment Case

Presented by TOC


This paper considers the possibility and desirability of an environment management system and an environment case. This paper intends to describe the principles and list requirements for these two concepts. Furthermore this paper intends to describe the aim of an environment management system and an environment case, and how they relate to each other and to other cases (e.g. safety case, human factor case, etc.).

This working paper provides information material and recommends IFATCA Policy on the issue. Furthermore the paper provides guidelines on how IFATCA should continue on the subject.


1.1 Environmental issues in ATM have been studied by IFATCA for many years. As a follow up it was considered necessary to study the environmentally driven procedures in ATM to establish the interrelation of these procedures in regard to the individual environmental domains e.g. aircraft noise and aircraft emissions. For example, a noise friendly procedure could easily result in an emission unfriendly procedure. For clarification, an environmentally driven procedure is a procedure primarily introduced for the benefit of environmental issues like aircraft noise and emissions of greenhouse gasses.

1.2 The preservation of the environment is a subject that will continue to influence political and industrial agendas and aviation in particular due to the influence of public opinion. For instance, industrial pollution of the air (smog excepted), which people do not really physically encounter on a daily basis, may have a lower priority for the public than aircraft noise. Aircraft noise is an issue that people encounter personally from day to day, and therefore is something that has much influence on the public. However, the need for reduction on emissions of greenhouse gasses has strengthened in recent years.

1.3 IFATCA’s Technical and Operations Committee (TOC) was tasked to investigate the need for an independent assessment methodology to assess the various individual environmental factors and to understand their interrelation. ATCOs should be protected from having to balance and prioritize these factors while working traffic. Furthermore TOC was tasked with investigating the need for IFATCA Policy on environment case, and explaining how an environment case should be conducted.


2.1 Various environmental interests

2.1.1 Environmentally driven procedures in ATM often have conflicting impacts on the individual environmental interests e.g. aircraft noise versus aircraft emissions. A noise friendly procedure often results in an emission unfriendly procedure. For example STARs and SIDs are often primarily developed, after considering operational factors like terrain, obstacles and airspace structures, to reduce the effect of aircraft noise. Furthermore, environmentally driven runway configurations are regularly selected mainly on the basis of noise abatement procedures and therefore trading off with operational requirements like wind components, navigation and landing aids.

2.1.2 The design of STARs and SIDs to reduce aircraft noise by avoiding populated areas often results in longer flight time, which automatically results in the increase of aircraft emissions and fuel consumption. Runway configurations based on noise abatement regulation can lead to extended taxi distances, which automatically results in the increase of aircraft emissions and fuel consumption. Furthermore these environmentally driven configurations could lead to complicated dependent approaches and departures.

2.1.3 At Amsterdam Schiphol dependent parallel approaches are sometimes operated exclusively for noise abatement reasons, while other (emission friendly) runway configurations are available. Aircraft dedicated for one runway need to turn to base leg at 2000ft, and aircraft dedicated for the other runway need to intercept the ILS at 3000ft. This automatically results in undesirable approach configurations for the aircraft, and also complicates the introduction of Continuous Descent Operations (CDO).

2.1.4 Another example of an environmentally driven procedure at Schiphol Amsterdam is a newly placed runway for noise abatement (RWY 18R/36L). The far placed position of the new runway results in extended taxi distances, which results in the increase of aircraft emissions. The noise friendly runway 18R/36L is preferred over an emission friendly runway 18C/36C, although either runway could be used operationally. This kind of trade-off will soon pose serious difficulties at and around noise driven airports.

2.2 ICAO

2.2.1 ICAO is conscious of its responsibility and that of its contracting States; “to achieve maximum compatibility between the safe and orderly development of civil aviation and the quality of the environment” (Assembly Resolution A35-5). ICAO activities on the environment are primarily focused on those problems that have the largest impact, namely aircraft noise and aircraft engine emissions. ICAO does not formally address the potential interference between aircraft noise and aircraft emissions caused by environmentally driven procedures.

2.2.2 In 2010 at the ICAO Assembly 37 the following key elements were incorporated:

1) Further endorsement of the global aspirational goal of 2 per cent annual fuel efficiency improvement up to year 2050;

2) a medium-term global aspirational goal from 2020 that would ensure that while the international aviation sector continues to grow, its global CO2 emissions would be stabilized at 2020 levels;

3)further work to explore the feasibility of a long-term global aspirational goal for international aviation;

4) development of a global CO2 Standards for aircraft aiming for 2013;

5) development of a framework for market-based measures, including further elaboration of the guiding principles adopted by the Assembly, and exploration of a global scheme for international aviation;

6) concrete steps to assist States to contribute to the global efforts;

7) de minimis provisions to ensure that States with small contributions to the global air traffic are not burdened disproportionately; and

8) States’ action plans, covering information on CO2 emissions reduction activities and assistance needs.

It is relevant to note that aircraft noise is not mentioned in any of these key elements, but it was extensively addressed in ICAO Assembly Resolution 37-18.

2.2.3 ATM is expected to become more and more performance driven, which clearly influences ICAO’s approach on the issue of guidelines, Standards and Recommended Practices. In Doc 9882 ICAO explains that a performance case could be considered in conjunction with a safety case, together with a human factor case and an environment case. A performance case could be conducted to address all issues within ATM. Depending on the issue (technical, procedural, legal, professional or environmental) a safety case, a human factor case, business case, an environment case, or all of the above could be part of a performance case.

2.2.4 ICAO Doc 9882 Manual on Air Traffic Management System Requirements:


2.1.1 General

The global ATM operational concept envisions a system that is service-oriented, performance driven and predicated on the guiding principles described in the OCD (Global Air Traffic Management Operational Concept, Doc 9854). To fulfill this vision, the ATM system shall:

a) ensure that performance forms the basis for all ATM system development [R97a)];

b) treat performance as a whole, that is, considering all the ATM community expectations and their relationships [R185];

Explanatory text: The holistic treatment of performance should be done by means of a system performance approach resulting in performance cases. A performance case can be seen as the combination of the various cases that together address and balance all areas in which the ATM community has expectations, e.g. the safety case, together with the business case, together with the environment case.

c) ensure the establishment of performance cases (safety, business, environmental, etc.) before Implementing changes [R186];

d) ensure that performance targets are defined, regularly reviewed and monitored [R97b)];

e) establish interchange of global benchmarking performance data as a cornerstone of ATM system management [R97c)];

f) ensure that all information for performance management is available to the concerned parties transparently and that information disclosure rules are in place [R187];

g) ensure that any performance management system establishes rules for, among other things, performance measurement, performance maintenance, performance management and performance enhancement [R103];

h) establish quality of service requirements to support provision of services within the ATM system [R158a)];

i) ensure that quality of service includes performance requirements related to availability, continuity, reliability and integrity [R158b]; and

j) balance the expectations of the ATM community [R188].

2.2.5 Although the “environment case” is mentioned in Doc 9882, ICAO has not yet explained what an environment case exactly is. IFATCA is of the opinion that the concept of an environment case should be taken up to the next level, and progressed into the development of a methodology through an environment management system with the environment case as an outcome. Content, form and outcome of an ATM environment case shall be developed. As it is very difficult to identify a “polluter pays principle “(such as the emission trading scheme for the users) for ATM, there is a need to reflect at the earliest possible opportunity on which elements could compose an environment case. Only by introducing an environment management system it will be possible to identify the various relevant environmental factors within procedures, which thereby enable the appropriate authorities to establish the required priorities on a strategic level.

2.2.6 For clarification it should be stated that the environment management system IFATCA has in mind is different from the existing industrial concept of an Environment Management System, an ISO 14001 aligned EMS, also promoted by CANSO. The industrial concept of an Environment Management System is a tool to facilitate the management of environmental issues with the intention to reduce the industrial impact within the environmental domain (fuel consumption, electricity, heating, etc.). IFATCA’s environment management system is intended to facilitate the management of environmental issues on an ATM related level. And it is not only intended to reduce the environmental impact, but also to identify the effect and interrelation of the various environmental constraints in correlation with operational procedures.

2.2.7 The name “environment management system” is not necessarily the one to be used in the concept of IFATCA; to prevent confusion it would even be advisable to use a different name. Nevertheless for the study of this subject the naming is not so important, but for the clarification of the system reference other ATM systems (e.g. SMS), it is preferred to continue with the name “ATM environment management system” within this paper.

2.3 IFATCA Policy is [ATS 3.25]:

“In the operation, maintenance and development of the ATM system when balancing the requirements of safety, efficiency and the environment, the level of safety shall always be maintained or improved.

In case environmentally driven procedures are introduced in the ATM System, these must be introduced taking into consideration the increased complexity for the controller. This complexity must be managed at the appropriate, strategic, level. A trade off between environment and capacity must be considered as part of this management of complexity, as safety is paramount.”


2.3.1 IFATCA’s Statement on Future ATM:

“Each member of the ATM community is individually responsible for behaving in an environmentally responsible manner”.

And according to IFATCA:

“…the combination of all ATM activities is a community activity and there will be a level of shared commitment, collaboratively agreed, to the ATM system operating in an environmentally sustainable way”.

This implies that IFATCA accepts responsibility in managing the environment. However, the increase of controller workload, due to environmentally friendly procedures, should remain acceptable and the mitigation of this workload could be a capacity reduction. Obviously, safety needs to be demonstrated, and therefore an unacceptable increase in workload must be mitigated at all times.

2.3.2 As mentioned in previous IFATCA studies, the balance between environment and industry is affected through environmentally driven procedures when introduced in ATM. The same applies for the balance between aircraft noise and aircraft emissions, when an environmentally driven procedure is primarily focused on one of the two issues.

Fig. 1 Environmental factors balance

IFATCA considers safety to be paramount, and therefore the trade-off can never be environment over safety. For that reason IFATCA believes the trade-off should be environment over capacity, for which the appropriate authorities should set the priorities on a strategic level.

2.4 At the IFATCA Conference in Dubrovnik a presentation on the environment in ATM was given at a panel session focused on that subject. One of the conclusions from that presentation was the need for an independent assessment methodology to safely assess the various environmental factors and to understand their interrelation. This was to protect the controller from balancing these various environmental factors while working traffic.

2.4.1 The IFATCA environment panel in Dubrovnik clarified issues on the environment in ATM by identifying the individual factors and stakeholders in relation to tools and actors/influence. Categorizing all factors, actors and tools, and dividing them into layers, results in a transparent overview. The table below could assist in identifying conflicts and influence of contributing factors.

Fig. 2 Categorization in layers

2.5 An ATM environment management system analogue to a safety management system should address conflicting environmental constrains, and must be based on an independent assessment methodology to assess the various environmental factors. It should map the environmental impact including the interrelation of individual environmental aspects; this outcome is the environment case. This case should also measure the impact of the various aspects against an agreed environmental performance target.

2.5.1 IFATCA acknowledges the need for action on behalf of environmental protection, and also wants to participate in the improvement of handling environmental issues. In addition IFATCA stresses the need for balance between the individual elements (capacity, efficiency, safety and environmental benefits), addressing both working and environmental constraints. The study of the individual aspects of environmental issues within an ATM environment management system should make clear exactly what the individual factors enhance. This puts the appropriate authorities and users in a better position to weigh up the different aspects and to prioritize them. It should be clear that the appropriate authorities are the principals and the controllers are bound by the environmental constraints, therefore removing the controllers from making environmentally driven decisions on priorities on an operational and tactical level. Nevertheless, controllers should be involved in the development and decision making of environmental constraints on a strategic level.

2.5.2 The environment management system should at least address the following questions:

  • Are ATM procedures needed or/and in place for noise abatement?
  • Are ATM procedures in place for the reduction of emission of greenhouse gasses?
  • Are ATM procedures optimized for all individual environmental factors? (This study could identify if some environmental factors are subordinated to other factors).

2.6 An environment case must be combined with the safety case, the human factor case and the capacity case into an overall performance case. The performance case addresses the entire system and should provide that certain procedures and solutions are not introduced without considering the individual environmental aspects. For example, nowadays a safety case will consider the operational impact of a system change mostly without considering the interrelation of the relevant environmental aspects. This limits a possible overview of the consequences of a certain change, while this could be covered with an overall ATM performance case. A performance case should make clear what consequences a change has on the total ATM system, including safety, environmental and human factors. This is in harmony with the IFATCA statement on Future ATM: “Performance driven ATM will be the future”.

2.6.1 An environment case should be a documented body of evidence that provides an argument that a certain procedure is optimized for individual environmental factors (e.g. noise, emission of greenhouse gases and visual pollution) as prioritized by the appropriate authorities. The environment case should provide sufficient argument to assist the appropriate authorities in prioritizing the individual environmental factors on a strategic level.

Fig. 3 Prototype environment case

Considering the figure above, by addressing all the interrelated individual actors and influences within (environmental) procedures, transparency must be achieved by calculating the actual values of the individual environmental factors. The outcome of these calculations must be compared to optimize procedures for individual environmental factors, or to set preferred priorities.

2.6.2 An environment case should document and make transparent what the actual produced amount of emissions and noise is due to certain environmentally driven procedures. The amount of noise and emissions can be calculated in fixed values. By identifying these various values it should be easier for the appropriate authorities to set and meet identified priorities.

2.7 IFATCA should not wait for other stakeholders to develop provisions for an ATM environmental management system and an environment case. IFATCA should continue to play a decisive role in the development of those conclusive provisions. By determining requirements for an ATM environment management system and environment case, IFATCA will be able to maintain its advanced position to develop the provisions, preferably in collaboration with international stakeholders, to promote to ICAO. IFATCA should support ATCOs through the prevention of requiring them to make tactical decisions based solely on environmental issues while working traffic.

2.8 Environmentally driven procedures that address both noise and emissions are Continuous Descent Operations (CDO). TOC has also studied (B.5.9) the ICAO (Draft) Manual on CDO, Doc 9931, for the IFATCA Conference of 2011.

2.8.1 A few examples which could be applied to environmentally driven procedures in general:

  • When a distant runway is used to reduce the impact of noise, the consequent increase in emissions should be made clear.
  • When using runway configurations for noise abatement, calculations should make clear the required extra fuel consumption and emissions due to non-economic flight procedures during the approach and the extra-required track miles.
  • When developing SIDs and STARs and increasing the track miles and/or introducing a noneconomic flight path (e.g. vertically) due to noise abatement, additional fuel consumption and emissions should be calculated and taken into consideration.

It is important that the conflicting consequences of the individual environmental constraints are transparent.

2.9 ICAO Member States are responsible for the (safe) provision of navigation facilities and services in their airspace. It is also their responsibility to determine the priorities between aircraft emissions and aircraft noise on a national political level. These priorities must be established and managed on a strategic level to prevent ATCOs from being confronted with this kind of decision making on an operational level. Regardless which one of the environmental issues gets priority, safety shall remain paramount.


3.1 Presently within Safety Management Systems a safety case typically does not consider individual environmental aspects in the development of the ATM system. Independent and detailed assessment methodology is required for assessing the various environmental factors and understanding their interrelation with the ATM system.

3.2 Increased complexity for the controller must be managed at the appropriate strategic level. This includes a possible trade-off between environment and capacity, as a trade-off with safety is unacceptable.

3.3 Transparency is required to highlight the consequences of environmentally driven procedures on the individual environmental aspects, and to enable national authorities and ANSPs to set the desired priorities between the individual environmental aspects. An adequate report of the actual amount and value of the various individual environmental factors is therefore crucial.

3.4 ICAO requires an ATM system to ensure the establishment of performance cases (safety, business, environmental, etc.) before implementing changes.

3.5 An ATM environment management system should be the instrument to ensure, through an environment case, that all individual environmental aspects are addressed within an overall performance case. An environment case should also identify the interrelation between the individual environmental aspects of new procedures.

3.6 By determining the requirements for an ATM environmental management system and an environment case, IFATCA can continue to play a leading role in the development of the conclusive provisions for an ATM environment management system and environment case in collaboration with international stakeholders.

3.7 In addition to IFATCA’s Statement on Future ATM, additional action by IFATCA’s Executive Board is required to properly manage environmental issues in ATM. This additional action should include establishing an Environmental Vision and Strategy and considering co-operation with international stakeholders to collaboratively manage environmental issues in ATM.


It is recommended that;

4.1. IFATCA Policy is:

Individual environmental aspects shall be considered by an ATM environmental management system and documented in an ATM environment case as part of an overall performance case.

and is included in of the IFATCA Technical and Professional Manual.

4.2 IFATCA Policy is:

Provisions for an ATM environment management system should comprise at least the following requirements:

  • Ensure that the level of safety shall be maintained or improved when environmentally driven procedures are introduced;
  • Ensure that all individual environmental factors are identified and considered while establishing procedures;
  • The actual values (noise levels, fuel consumption and the amount of emissions) of the various individual environmental contributors of new or existing procedures should be established in detail for transparency reasons;
  • The interrelation of the various individual environmental factors should be identified and addressed.

and is included in the IFATCA Technical and Professional Manual.

4.3 IFATCA Policy is:

Provisions for an environment case should comprise at least the following requirements:

  • An environment case is a documented body of evidence that provides argument that a certain procedure is optimized for all individual environmental factors as prioritized by the appropriate authorities;
  • An environment case should provide a detailed overview to the appropriate authorities for the determination of priorities of the individual environmental factors on a strategic level.

and is included in the IFATCA Technical and Professional Manual.

4.4 The IFATCA Executive Board should produce an Environmental Vision and Strategy. This Vision and Strategy should consider co-operating with other international organizations and stakeholders to develop the concepts of ATM environment management system and ATM environment case, with the ultimate goal of promoting these to ICAO.


ICAO Annex 16 Environmental Protection.

ICAO Doc 9882 Manual on Air Traffic Management System Requirements.

IFATCA WP 93 Arusha 2008 – Environmental Issues in ATM.

CANSO – Introduction to Environmental Management Systems (June 2010).

Last Update: September 30, 2020  

April 18, 2020   696   Jean-Francois Lepage    2011    

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