EEUURROOCCOONNTTRROOLL && EEuurrooppeeaann aaiirrppoorrttss EEnn--rroouuttee ttoo eenn--rroouuttee ttiimmee--oorrddeerreedd ccoonncceepptt TTooddaayy’’ss aaiirrppoorrtt iinn ttoommoorrrrooww’’ss eennvviirroonnmmeenntt AAiirrppoorrtt nneettwwoorrkkiinngg RRooyy GGrriiffffiinnss,, DDiirreeccttoorr GGeenneerraall AACCII EEUURROOPPEE:: FFuuttuurree cchhaalllleennggeess ffoorr aaiirrppoorrttss CCaappttaaiinn RRoobb vvaann EEeekkeerreenn,, IIFFAALLPPAA:: RRuunnwwaayy iinnccuurrssiioonnss Skyway is a quarterly publication of the European Organisation for the Safety of Air Navigation, EUROCONTROL Volume 7, Number 37, Summer 2005 Editorial 3 Focus 4 EUROCONTROL and European airports 9 Enhanced airport throughput The “en-route to en-route” time-ordered concept 12 The airport operations programme 20 EUROCONTROL airport research and development 23 Today’s airport in tomorrow’s environment Stakeholder Forum 26 ACI EUROPE: future challenges for airports 29 Concept –Runway incursions Independent Platform Skyway Magazine is a EUROCONTROL publication. Articles appearing in this magazine 32 Airport networking do not necessarily reflect EUROCONTROL’s official policy. Publisher:Víctor M. Aguado Dateline Managing Editor:Gerhard Stadler Editor:Lucia Pasquini 34 Inaugural World Aviation and Environmental Summit [email protected] Editorial Team:Christos Petrou, Jean-Jacques Sauvage 36 ECAC/EU Dialogue with the European Air Transport Industry Linguistic Advisers:Language Service (DGS/LSEC) Layout:Frédérique Fyon Airport Capacity –Facing the crunch Photography and pre-press coordination: Christian Sampoux 38 Joint CAA FYROM/IATA & EUROCONTROL Airport Operations Printing:EUROCONTROL Logistics and Programme Regional Road Show, 5-6 April 2005, Skopje Support Services, Bureau DGS/LOG 39 Civil/Military Air Traffic Management Conference, Articles, photographs and letters from 23-26 May 2005, Prague readers are welcome. Whilst every care will be taken of material submitted for 40 IATA and EUROCONTROL help E-learning take off publication, the Managing Editor regrets that he is unable to accept for airline industry, 8-10 June 2005, headquarters, Brussels responsibility for any loss or damage. 41 15thACI EUROPE General Assembly, 23-24 June 2005, Munich EUROCONTROL Website: http://www.eurocontrol.int Report 42 Online with EUROCONTROL –www.eurocontrol.int 43 Introducing of automatic controller-pilot data link communications mbH breaks new ground G Deutsche Flugsicherung 444455 ECAJanElenlAax TVr HSgae enRdn eD dPsorCeioka rsPrn crr eh-e s cDaiedinirevdene cDtst’o estr vhB eEeulU or“eRp2amO0u0Ce 5(OnP tNCC aTaPnRtBhdOe- eSLri) in Emmexu peFleeaarttriiigmnoegneosnn tc aAelnw Ctareernd (t”rCeRDS) S © DF 46 Visits and agreements Dear Readers, Chers lecteurs, Over the past five years, Europe’s air Depuis cinq ans, le système de gestion du trafic aérien en Europe traffic management system has produced affiche d’excellents résultats. Entre 1999 et 2004, le trafic a augmen- l a some excellent results. Between 1999 té de 10% mais les retards, eux, ont chuté de 67%, sans que les coûts i and 2004, traffic grew by 10%, and delays ne s’accroissent en proportion de la hausse des performances. Qui r fell by 67% - yet costs have not risen in plus est, l’année 2004 a été la plus sûre jamais enregistrée en Europe o t tandem with increased performance. At en termes d’accidents. Ces résultats constituent, pour tous ceux d’en- i d the same time, in terms of accident rates, tre nous qui sont chargés de la gestion du trafic aérien, un succès E 2004 was the safest year ever in Europe. dont nous pouvons et devons nous enorgueillir. Dans le même temps, These results are something that all of us who are involved in air nous ne pouvons nier que le doublement prévu du trafic aérien en traffic management can and should be proud of. At the same time, Europe, d'ici à 2025, nous obligera à en faire beaucoup plus encore we cannot fail to recognise that with air traffic in Europe expected si nous voulons conserver les niveaux de sécurité, d’efficacité et de to more than double by the year 2025, we will have to do much rentabilité auxquels les passagers s’attendent désormais. more if we are to continue with the levels of safety, efficiency and Ainsi, pour maintenir un niveau d’efficacité adéquat, nous devons cost-effectiveness passengers are now coming to expect. étudier de près les domaines qui pourraient se révéler être les If we are to ensure ongoing efficiency in particular, we need to maillons faibles de la chaîne de gestion du trafic aérien. Les aéro- look closely at those areas that could prove to be the weaker links ports, en particulier, constituent l’un de ces domaines clés qui requiè- in the air traffic management chain. One key area that does require rent une attention spécifique. Malgré la baisse des retards enregistrée specific emphasis is airports. Despite the fall in delays over the ces cinq dernières années, la part des retards imputable aux aéro- past five years, the share of delays attributed to airports has ports demeure plus ou moins constante. Si cet état de choses n’a pas remained more or less constant. While this has not prevented per- empêché des gains considérables de capacité, il témoigne toutefois formance in capacity from improving dramatically, it is however an de la nécessité de traiter le problème critique de la capacité selon early indication of the need to address the capacity crunch in a une méthode systémique globale, qui intègre les aéroports. holistic systems approach which would include airports. Alors qu'aujourd'hui déjà, les aéroports représentent, parmi nos While already today airports represent one of the main limiting partenaires, l'une des principales entraves, il ressort d’une étude factors, a recent study ‘Challenges to Growth’ carried out by récente sur les “Défis à la croissance”, réalisée par EURO- EUROCONTROL and ECAC found that by 2025, airports will CONTROL et la CEAC, que les aéroports constitueront, d’ici à 2025, severely constrain traffic growth – with up to 3.7 million flights per un frein important à la croissance, puisque 3,7 millions de vols par annum not being accommodated – even if the latent capacity of the an ne pourront être pris en charge, même si la capacité potentielle airport network is fulfilled. 75% of European airports see no possi- du réseau aéroportuaire était pleinement exploitée. Quelque 75% bility of adding new runways in the next 20 years – despite the fact des aéroports européens déclarent ne pouvoir se doter de nouvel- that within 5 years the top 20 European airports will have severe les pistes dans les 20 prochaines années, alors même que les 20 capacity shortages. Much work has already been done to address plus grands aéroports européens souffriront d'une forte pénurie de the capacity crunch, and together with partners from across the capacité dans les cinq années à venir. De nombreuses actions ont industry, we are looking at how we can squeeze the last drops of déjà été menées pour pallier les problèmes de capacité, et nous capacity from the current system. étudions maintenant, avec les acteurs de l’ensemble du secteur But while we need to ensure that traffic can continue to grow, aéronautique, comment dégager les ultimes possibilités du systè- we also need to look at the other two key elements of the airport me actuel. challenge – safety and environment. Runway incursions are still Mais, si nous voulons assurer la poursuite de la croissance du considered one of the leading hazards and addressing this issue trafic, nous devons aussi tenir compte de deux autres éléments inti- successfully will require the widespread application of the mement liés au défi que pose la capacité aéroportuaire : la sécurité European Action Plan for the prevention of Runway Incursions. With et l’environnement. Les incursions sur piste sont toujours considé- global warming a major threat to our planet, and noise and emis- rées comme l’un des principaux dangers, qui ne pourra être com- sions of increasing public concern, airports should ensure that a battu avec succès que par la mise en œuvre, à grande échelle, du suitable environmental approach is built into all their activities. Plan d'action européen pour la prévention des incursions sur piste. In the three areas of capacity, environment and safety, the air Face à la lourde menace que constitue le réchauffement planétaire transport industry must work together, and adopt a cooperative et aux préoccupations croissantes du public à l’égard du bruit et des decision-making approach if we are to be successful. In this issue émissions, les aéroports devraient veiller à ce que toutes leurs acti- of Skyway, together with some of the main actors, we take a closer vités intègrent une approche environnementale appropriée. look at the issues surrounding this key question. Dans ces trois domaines que sont la capacité, l’environnement et la sécurité, les acteurs du transport aérien doivent, pour aboutir, unir leurs efforts et favoriser la prise de décision consensuelle. Dans ce numéro de Skyway, nous nous penchons, avec quelques acteurs de premier plan, sur différents aspects de cette question fondamentale. Víctor M. Aguado Víctor M. Aguado Director General Directeur général Skyway 37 - Summer 2005 3 EEUURROOCCOONNTTRROOLL aanndd EEuurrooppeeaann aaiirrppoorrttss AA rreecceenntt aanndd vveerryy ddeettaaiilleedd ssttuuddyy bbyy EEUURROOCCOONNTTRROOLL iinnttoo tthhee eevvoolluuttiioonn ooff ttrraaffffiicc ddeemmaanndd rreevveeaalleedd ssoommee ssiiggnniiffiiccaanntt iinnffoorrmmaattiioonn ffoorr aaiirrppoorrttss.. KKnnoowwnn aass tthhee CChhaalllleennggeess ttoo GGrroowwtthh 22000044 BByy PPaauull WWiillssoonn,, SSttuuddyy,, tthhiiss wwoorrkk uuppddaatteedd aa pprreevviioouuss rreeppoorrtt HHeeaadd ooff AAiirrppoorrtt TThhrroouugghhppuutt UUnniitt tthhaatt wwaass ccoommpplleetteedd iinn 22000011.. 4 s u c o F The EUROCONTROL and whilst this work continues, an addi- approach to airports tional EUROCONTROL focus was placed on airports in the 1990s. Although future traffic growth can be very difficult to predict due to the possi- For EUROCONTROL this was a new bility of unforeseen external factors, the experience, and certainly for the first high forecast over the period of the few years was a very difficult road to study, up to 2025, indicated that traffic tread. EUROCONTROL had entered a has the potential to increase by a factor world in which airports operated in a of 2.5. The same report also estimated very challenging commercial environ- however, that the airport network has ment, where there were many differing long-term potential for 60% capacity institutional operating arrangements, growth using existing or planned infra- where there were growing environmen- structure. tal pressures, and where it seemed new restrictions and new mandatory require- Figures such as these clearly indicate ments were a regular feature. Due to the that many airports in the future will need complex and diverse nature of airport to engage in high-intensity runway operations, it was obvious that in order operations, to ensure that the full poten- to make progress a team effort would tial of the runways is realised and where be needed. This would certainly involve required, that all latent capacity is airport operators, both with associations unlocked. and with individual airports, and to this end many close links have been estab- Experience has shown that it can take lished, not least with Airports Council many years to reach this point where a International – Europe, which has been runway can consistently deliver maxi- instrumental in designing the eventual mum possible throughput, using mini- EUROCONTROL Airport Programme. mum permissible separations. There Of equal importance are the air naviga- are many issues that must be carefully tion service providers and controller considered, such as controller and pilot associations, and input from the workload, human factors, possible con- Airlines. This latter point has been struction of new runway exits and achieved extremely effectively by access points and environmental establishing close links with IATA, who restrictions. have proved very willing to provide input from the airlines, which are of EUROCONTROL, which was created in course the main users of the airport air- 1960, has traditionally devoted its side operation. Finally very close coor- efforts towards the en-route arena, dination was established with the where capacity restrictions and conges- European Commission, which contin- tion initially manifested themselves. ues to initiate an R&D effort on airport Within this area there have been signifi- operations. From the outset it was obvi- cant achievements. Working closely ously considered essential that the with air navigation service providers EUROCONTROL effort should not dupli- and aircraft operators, the increase in cate any activities undertaken else- available capacity has been in the order where, but where possible should com- of 50% over the last few years. plement them. Enhancements in the operation of the Central Flow Management Unit and Having established these alliances, and other pan-European projects such as understanding the challenging nature the 8.33 mHz frequency division and of airport operations, the philosophy at the reduced vertical separation criteria the outset was to generate a low-cost have delivered huge benefits. The fact and operationally-focused programme that rapid progress was being achieved that would help airports to enhance in the en-route area was recognised, safety, efficiency and capacity, so that (cid:25) Skyway 37 - Summer 2005 5 EUROCONTROL and European airports (cont’d) s u c o F wherever possible projected traffic demand could be accommodated. EUROCONTROL was not going to identify gold-plated and costly solu- tions, or try to solve a problem that did not exist. In terms of airport operations there are many areas where significant improve- ments may be possible. Operations in poor weather, which in 2003 accounted for several million minutes’ delay is one such area, as are the existing fairly crude wake vortex separation criteria which are a huge constraint to runway capacity. The many prospective areas were debated with the Airport Operation Team, which is a group of around 70 representative airport stakeholders. After this debate, and following consul- tation with other airport representatives, the first EUROCONTROL Airport Programme was confirmed and initiat- Runway incursion Capacity assessment ed in 2001. The areas selected as high prevention priority in this first programme were: EUROCONTROL has produced a very sophisticated tool known as the ■ Enhancing safety by the prevention There is around one incursion per day Common Agreed Methodology for of runway incursions within the European area, and incur- Airport airside Capacity Assessment ■ Capacity assessment sions without doubt represent a high- (CAMACA) designed to accurately ■ Capacity enhancement risk area, evidenced by a number of assess the capacity of runways, taxi- ■ Capacity planning actual collisions over recent years. way and apron areas. This tool is now ■ Advanced Surface Movement available and has already been widely Guidance and Control Systems A very active working group, com- used. One important feature was incor- ■ Collaborative Decision Making posed of representatives from all porated in CAMACA in recognition of ■ The A380 wake vortex separation organisations involved in runway oper- the very high cost of building new taxi- criteria ations, has produced the European ways or runway exits. This “what if” fea- ■ Airport environmental mitigation Action Plan for the Prevention of ture can calculate the increase in procedures and measures. Runway Incursions. This has been capacity that would be achieved widely distributed and implemented, should any new infrastructure, such as Whilst it is recognised that not all areas and the majority of medium and large- runway rapid exit taxiways, be con- are covered, this Programme was con- sized airports now have local runway structed. The output from this feature sidered to include the high-priority safety teams in place. This is a complex can provide valuable input for the cost- items that should be dealt with as soon problem, and work continues to devel- benefit assessment of proposed invest- as possible. op this initiative further. There is close ments. cooperation with the FAA and Air Brief details of these projects follow Services Australia, with the objective of Capacity enhancement below. achieving total harmonisation of all pro- cedures. Due to the global nature of air As noted earlier, there will be a require- transport it is these regional differences ment for many runways to increase that can result in confusion and which their throughput as traffic grows. This is can and have resulted in many runway a complex process with many elements incursions. that need to be considered. The EURO- 6 s u c o F Executive control is not possible, and Continuous Descent they are used to supplement the visual Approaches (CDA) observations of the controller or provide the ability to monitor traffic in poor visi- A multi-discipline EUROCONTROL bility. team is developing guidance and sup- port resources for pan-European The new generation of surveillance ‘capacity friendly’ Continuous Descent equipment, which is now commercially Approach (CDA) technique based on available, is very sophisticated and has the provision of distance to go informa- the ability to carry out many functions. tion. The EUROCONTROL activity in this area is the definition of air traffic control Initial CDA concept-proving trials are procedures that will allow this equip- underway at Manchester and other tri- ment to be used to its full potential. The als at Stockholm-Arlanda Airport and first tranche of procedures has now Bucharest-Henry Coanda International been trialled at a number of major air- Airport (Bucharest) are planned. ports – it is the intention to submit these to ICAO for global adoption towards the Other environmental work end of 2005. The concept of Collaborative Collaborative Environmental Management (CEM) is also being developed and resources Decision Making (CDM) will be provided to airport operational Whilst airports can be awash with data stakeholders to help them to effectively CONTROL Capacity Enhancement and information, it is a fact that this respond to an airport’s environmental project has developed a step-by-step information is not always available to challenges. methodology that will facilitate capacity those who need it. In simple terms this enhancement. Key to this project, project is about delivering up-to-date which has already been tested and has information to the people who need it at CEM stakeholder liaison schematic produced increases in capacity, is a the correct time, which will then signifi- close working relationship between cantly enhance the quality of decisions, Environment controllers, pilots and airport operators. so reducing delay and resulting in Regulator Community Planning Authorities increased utilisation of resources. Local Govenment Airframe and Aviation Regulator Engine Manufacturers Capacity planning Development of enhanced procedures Other ATSPs FMS suppliers and processes continues at four Airport Operator This project covers the development of European airports, whilst the early ATSP OApirecrraatfotr a medium-term capacity plan that can applications are being implemented at CEM be implemented over a five-year period many other locations. as traffic increases. Constraints that Community, Government, NGOs International Agencies (EUROCONTROL) may restrict capacity such as airspace This project is delivering significant EU, ECAC, ICAO etc. and environmental considerations are benefits in terms of increased efficiency. included. Although still under develop- ment, this process has been very Environmental CEM development model successfully trialled at two European responsibility airports. Environmental work is of such impor- Advanced Surface Level 4 MCThoeon vptreroombllee mSn ywts itGthe uthmied sfai rns(Atc g-eeSn MaernaGdtiConS o)f tEecinaosninttvvicaaeierbrtois lntin shgamha llete pdanh .tE saaeUlTs pheRaUseOr n aoCitetfe On flvEhNigiUarThosRRtn ,O OmanCLnoe’Osdwn tN wTbtiRlelef aiObremsneLt Collaborative Learning CJInoofLLinoneesrt vvmuAeeltaclla tt32tiioioonnn Conflict Resolution airport surface radars was that there Environmental Programme in late 2005. Level 3 Understanding were no clear guidelines on how they This Programme will be focussed on should be used operationally. airport issues and will include: (cid:25) Skyway 37 - Summer 2005 7 EUROCONTROL and European airports (cont’d) s u c o F Working with European airports, ACI These then are the elements of the first possible to determine if the cross- EUROPE, IATA and other key stake- airport programme and environmental winds destroy or move the vortices holders, the Environmental Unit is also work which are proving to be very suc- away from the runway. If this is the presently developing the beta-test ver- cessful due to its highly operational case, then reductions in the separation sion of ‘SOPHOS’, a web-based airport focus. As noted earlier there are other criteria may be possible. and environment resource. SOPHOS areas that need to be covered, and will contain around 20 support resource several of these are now being devel- The EUROCONTROL approach to air- modules including: oped for inclusion in a second airport ports is to work as a team with airport programme. These include the use of operators, air navigation service ■ recommended practice guidance time-based separations on final providers and airlines. This approach is (quantification, evaluation and man- approach, replacing the traditional dis- essential, and the collaboration is prov- agement) tance-based criteria. The objective is ing extremely successful. All develop- ■ a secure benchmarking facility to try to overcome the significant loss ments and concepts are put before (being developed with ACI of runway capacity that is inevitable stakeholders on a regular basis to con- EUROPE) whenever there is a headwind of firm the EUROCONTROL work remains ■ guidance on the ATM-relevant greater than 15 knots on final focused, cost-effective and will pro- aspects of undertaking an EIA approach. This is a common weather duce real benefits. ■ a European ATM and Environment feature in Europe, and is a factor that Information Repository results in considerable disruption. The EUROCONTROL airport vision ■ simple interactive environmental Early development work is nearing an remains to provide cost-effective solu- significance assessment tool end, and the results to date indicate tions that will help all airports to operate ■ provision of basic airport-specific that this is in a feasible concept. Other to their maximum potential, whilst noise and emissions data using areas of work that are in the planning enhancing the safety levels of runway flight data stage are targeted on improving oper- operations. This vision, with the active ations in poor weather and, as men- input of airport stakeholders, is being In addition, the Environmental Domain, tioned earlier, the updating of wake rapidly achieved and the existing alongside the EUROCONTROL vortex separation criteria. This last Airport Programme is scheduled to fin- Experimental Centre’s Society, Eco- area is important, and I believe signifi- ish in 2006, when all of the projects will nomy and Environment Unit is also sup- cant improvements can be achieved in be complete. A second programme is porting a range of international ‘airport some areas. As an example, at the under development to complement the and environment’ initiatives including moment, even when there are signifi- initial activities, which again will be data provision to policy decision- cant crosswinds on a runway, air traffic intended to enhance capacity and also makers, ICAO-CAEP, SOURDINE, controllers are required to apply the assist in recovering some of the capac- AERONET and XNOISE standard wake vortex separation crite- ity lost in poor weather. ■ ria. With the new generation of LIDAR- A380 separation criteria type equipment, which can actually track vortices in real time, it is now The objective of this late addition to the EUROCONTROL Airport Pro- gramme is to confirm the separation criteria of the A380, which will enter into service during 2006. The project is being jointly run with the JAA, FAA, ICAO and Airbus. met © Photo: D. S 8 s u c Enhanced airport throughput o F The “en-route to en-route” time-ordered concept By 2004 the cost and impact of airport-related delays had reached parity with those for en-route and were recognised as a major constraint to growth1. The EUROCONTROL “Constraints to Growth” study published in early 2005 confirmed this. It recorded that if traffic volumes continued to grow at even the conservative predicted rate and airport throughput capacity problems were not resolved, thirty percent of traffic demand would not be accommodated. By Ken Reid, Head of Airports and Clearly change is needed. Environment Domain Background ration minima to accommodate wake- Time-ordered system vortex generation and the adjustment ATC operations are one (significant) of distance-based separation to reflect General component of the complex interaction strong headwind conditions. Airport operations constitute a complex of diverse actors and services which interaction of many dissimilar activities collectively form Airport Operations. All of the above will aid airport undertaken by diverse organisations Improvement in runway throughput has throughput, but except for ongoing ranging from airlines, air crews, han- been facilitated by “high-speed” exits capacity modelling, each can be dling agents, engineering support, fuel, and they work. Airport surface regarded as a “one-shot” gain. There catering, and the providers of safety throughput is aided by Advanced is just so much concrete that can be and security services. Many services Surface Movement and Guidance laid before the physical limits of an air- are provided under contract and no Systems and the growing adoption of port or the benefits to be obtained physical links exist between the part- Collaborative Decision Making is pro- from such an investment are reached ners. In consequence, coordination viding efficiency gains. or exceeded. and management of these different activities may be dysfunctional, and a Further capacity gains will be achieved So how can the theoretical capacity of demanding, complex task be made 1- EUROCONTROL Performance Review through the implementation of research an airport be exploited and additional more challenging by the absence of a Commission Report conducted into the redefinition of sepa- capacity be made available? common situational picture. Is the air- PRR7 refers. (cid:25) Skyway 37 - Summer 2005 9 Enhanced airport throughput The “en-route to en-route” time-ordered concept (cont’d) s u c o F can likewise plan their efficient use of capital. Now compare this with the dysfunctional “organisation” of air- ports. Situational awareness The absence of a common picture, the lack of effective in-time communication and cooperatio and the hoarding of information results in a somewhat con- fused “picture” which when events run to schedule has little impact. The con- verse is true when even minor changes to the plan occur. If effective means of understanding and cooperation were available, improved situation aware- ness would benefit all airport opera- tions stakeholders at little or no cost. craft on schedule or not? Each partner mitigation instituted ahead of the event. Effective management of assets would may use a “different” source of time to Unforeseen events occur but the result in reduced capacity loss, an determine when assets should be “planned” system ensures that all increase in throughput and a direct deployed. Time sources used include actors are identified, their roles clearly return to the bottom-line of the airport the published timetable, airport infor- specified, and that effective means of operator. The airlines would gain from mation system (FIND) and aircraft communications exist to ensure that “extra” capacity and reduced costs of ACARS messages. The absence of collaborative decision making can disruption, and support services from the common picture means that asset apply. With a time- ordered process a increased business and the ability to deployment is frequently not har- company can plan its investments in redeploy contingency staff and equip- monised with real-time traffic move- plant, machinery and people and ment to operational and therefore rev- ment and inefficiencies are introduced ensure that these are tailored to actual enue earning tasks. Terminal operations and capacity lost. need to efficiently use capital. would benefit from additional through- Moreover, the time-ordering of the put. And the passengers would gain Due to its “glamorous” image, it is fre- delivery of components means that the from a more faithful adherence to the quently forgotten that aviation is just a contracted suppliers of these goods timetable. service industry. The task is to move a commodity or person from one prede- termined point to another. In per- forming its role, it executes specific, identified tasks in accordance with a clearly defined, pre-ordered se- quence. Other industries perform in a similar way. Take for instance vehicle manufacturing2. Time-ordered processes 2- Vehicle The vehicle production line is designed manufacturing for the efficient assembly of compo- has been used to illustrate a nents through a combination of just-in- logical, planned time delivery of parts and the effective process only. It is acknow-ledged performance of clearly defined tasks that such processes within a time-sequenced series of are not subject to the many and diverse events. The process is planned, man- points of potential aged and potential disruptions to the failure which characterise ATM. system identified at an early stage and 10
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