Aircraft turnaround made visible from a TBO/SOA perspective
On 29/04/2011, in Buzzwords explained, by steve
Trajectory Based Operations (TBO) and Service Oriented Architecture (SOA) are two concepts rather new to air traffic management (ATM) and apparently they continue to cause some head scratching when it comes to agreeing what TBO really means or how to define services in the ATM context. In this article I will attempt to explain a few relevant aspects of those concepts and will also try to visualize the concepts using the aircraft turnaround as an example.
Why the aircraft turnaround? Because we see that in spite of the original SESAR Concept of Operations having made clear that the trajectories of flights performed by the same aircraft are in fact always connected via the given airframe, some experts are now laboring to show that this is so and are trying to bring in new constructs to account for this “connection”. The trajectory does go through important metamorphoses during the turnaround and so using that phase of the operation gives us the opportunity to examine TBO and SOA in all their glory.
But first a few basics.
The concept of services.
“Service” is a word that can mean different things depending upon the context in which it is being used. In general, the context is based upon a consumer/supplier relationship. Further, a hierarchy of services can exist with, for example, a high-level service being made up of a number of lower level sub-categories of services. Therefore, it is very important to ensure that the nature, scope and detailed characteristics associated with each service are clear and unambiguous each time it is used, including defining who is supplying what to whom.
Services may be defined from a business perspective or an IT perspective.
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Do you really understand – Trajectory based operations (TBO)?
On 04/02/2011, in Buzzwords explained, by steve
There is a misconception in some air traffic management circles that trajectory based operations is simply business as usual except that the current, notoriously imprecise ground generated trajectories are replaced by more accurate, 4 D trajectories and that is all there is to it. Some will add that parts of this 4D trajectory might be sourced from the FMS or an airspace user ground system… While there is truth in all this, TBO is much more. Much much more and significantly, if the other aspects of TBO are not considered, the potential for benefits inherent in TBO is reduced significantly.
So, what is trajectory based operations?
First and foremost we must look at the basis of the existing operation. Air traffic management has grown historically along an airspace based paradigm. Airspace as such was a given so it stood to reason that early ATM experts set out to define airspace volumes which they thought would best fit the traffic they expected and established air traffic control units to fit the task foreseen in those volumes. When aircraft arrived, they were obliged to fly within the confines of the defined airspace and if their needs differed from that envisaged, the aircraft trajectory was bent to fit the picture. Of course this is a bit of an oversimplification but to this day, ATM is being done on this basis.
The end-to-end trajectory played almost no role in this game. To illustrate the point, juts consider that until recently the Central Flow Management Unit calculated expected sector loads on the basis of a trajectory the vertical dimension of which was famously inaccurate while ground ATC systems generated their own trajectories for their own airspace and these often did not tie up with the trajectory dreamed up by the neighboring unit. All this time however scores of experts everywhere worked furiously on airspace design and organization… Only a blind person could fail to see that this legacy, airspace based paradigm had to go if the volume and efficiency demands of increasing traffic were to be met.
Things were not helped at all by the fact that controllers were handing flights as if they were born just outside their sector boundary and went into the big blue yonder when they exited their sector. In other words, they only ever looked at a small part of the trajectory with little regard to what was or was not happening further downstream. Conflict free handover was the almost the only aim.
Because of the way airspace was used in the past, popular ATM wisdom came up with the notion that airspace was a scarce resource and it had to be organized better to save the day. This notion was a dangerous one because for a long time it did divert attention and effort from looking at the real problem. Trajectories…
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Trajectory based operations (TBO) – Still not properly understood in SESAR? Take 2.
On 18/01/2011, in SESAR's Palace, by steve
You may recall that a while ago I had written an article with the same title, expressing concern that this all important element in the SESAR Concept of Operations was apparently still not properly understood by some of the “experts” working on the subject.
Recently another paper dealing with trajectory management crossed my desk and on reading it I started to wonder: have these people not read the CONOPS at all? Mind you, the paper comes from a major SESAR partner who should know better… But apparently they do not.
The paper is entitled “Use of the SESAR RBT in ATM Systems”. RBT in case you did not know stands for Reference Business Trajectory and this is the trajectory that “the airspace user agrees to fly and the ANSP agrees to facilitate” to quote the relevant part of the SESAR Concept of Operations (CONOPS).
The purpose of the paper, by its own admission, is to prompt discussion of the trajectory issues within the SESAR program and in particular to ensure that they are addressed by Work Package B. In other words, the paper is arguing that alongside the RBT, the various other types of trajectories that exist in local systems must also be recognized and treated in SESAR. Since the CONOPS already contains references to all those “other” kinds of trajectories, one cannot but wonder: what do the authors of the paper have in mind? Why would SESAR ignore the CONOPS references to those other trajectories? Or have the authors not read the CONOPS and are now thinking that they have discovered a gap in that document?
I will not even attempt to figure out this aspect. There are many other elements in the paper that should make anyone familiar with trajectory based operations want to cry.
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Functional Airspace Blocks (FAB) – New category on Roger-Wilco
On 03/01/2011, in FAB News, by steve
FABs may be the highest political priority for the European Commission and they certainly are the source of high flying political statements, but I still do not like them. Why? Well, the idea when it first came up was a good one. At the time, functional fragmentation of air traffic management in Europe was costing airspace users billions and in spite of all the projects being considered, there was little hope for structural reform.
In order to break the logjam, and fully aware that there was no hope for getting the whole of Europe to co-operate and create a single sky, the EC very pragmatically proposed that groups of States get together and create functional airspace blocks (FAB) along the lines of their ATM “interests”, optimizing and aligning procedures and services inside their FAB… This way, the argument went, at least there would be a single sky of sorts inside the FAB and later on the FABs themselves could be harmonized for a truly single European sky.
Pragmatic and logical as the idea may have been, it was not received by the ANSPs with open arms.
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Trajectory based operations (TBO) – still not properly understood in SESAR?
On 26/11/2010, in SESAR's Palace, by steve
Following Henning’s article about the fate of the original SESAR Concept of Operations (CONOPS), I received a slew of mails basically confirming his point of view and worries. Of particular concern seems to have been a document dealing with trajectory management…
People who had seen this document were of the opinion that it was little more than a reiteration of the legacy way of working with no visible attempt to bring things in line with the spirit, let alone the words, of the CONOPS.
Why am I not surprised?
During the definition phase we had a very hard time getting people to understand why the legacy system, based on managing airspace and massaging individual aircraft left and right had to give way to something else that took a broader view than is the event horizon of a controller working his or her sector.
The concept of trajectory based operations (one of the mainstays of NextGen also) does exactly that. The system is run on the basis of managing trajectories end to end with situational awareness shared by all concerned and hence both strategic and tactical decisions being aligned, safety permitting, with the business intentions of the owners of the trajectories. Airspace is shaped to allow the undistorted inclusion of the trajectories rather than trajectories being bent to fit the airspace.
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Performance Based Navigation (PBN) – Why the “N” should be an “O”
On 11/03/2010, in Buzzwords explained, by steve
The abbreviations game
In aviation we seem to be creating abbreviations at a rate that raises the specter of our grandchildren not having any usable combinations left any more. This remark from a well respected colleague of mine who used to work for UPS airlines does in fact indicate a few problems that go beyond the scarcity of available unique letter combinations and which, as we will see, affect our daily work in all kinds of unexpected ways.
This is not aviation CNS...
Consider the well known CNS formation which, we all know, stands for Communications, Navigation and Surveillance. Whoever came up with the abbreviation CNS probably had no idea how much damage their invention would cause in air traffic management by perpetuating the kind of silo mentality that keeps many organizations hopelessly divided and some experts retreating into their respective ivory towers.
If at least the inventors had the good sense of putting those letters into some kind of logical order, like history, which would have given us NCS… We did navigate first (as in trying to find our way by reading the names of train stations and flying along highways), then communicated, initially with lights and hand signals and later via radio and most recently we do surveillance also. Not that NCS would have been any better at driving the silo mentality from the face of the earth.
Of course in the old days there was some logic in looking at navigating and communicating as something totally different from each other. You trained for one or the other, aircraft carried separate navigators and radio operators and when radar came along, the wizards of that kit were a completely new breed yet again. It was only logical also that separate fiefdoms should grow up along the letters NCS with hardly any horizontal contact between them. That they should fiercely protect their respective domains was perfectly natural…
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Is the industry ready for this?
On 19/01/2010, in Environment - Without hot air, by steve
The northern hemisphere has just gone through its snowiest January days in 40 years and polar temperatures reached as far South as Orlando in Florida. Sure, this is not abnormal some may say… but what if we do not have to wait forty years for the next episode?
An Air France flight en-route from Brazil to France encountered so severe turbulence that they issued a Mayday call but subsequently they completed the flight without incident. As we all know, AF447 was less fortunate.
Over the past 18 month or so, there were several incidents where unexpected severe turbulence caused passenger injuries…
And now the European Aviation Safety Agency (EASA) says, as reported in Aviation Week, that “climate change could be contributing to more extreme weather conditions at high altitudes that have not previously been encountered by aircraft”.
Make no mistake, although the current investigation of the crash of AF447 talks a lot about the problems with pitot tubes prone to freezing, there is a much more sinister implication here. Pilots are trained to handle situations where pitot tube data is lost or is unreliable… You cannot however train pilots to fly an aircraft with a wing or stabilizer gone. This is the point… who says extreme weather can only come in the form of extreme cold and not also as extreme turbulence?
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U.K. airspace “developments”?
On 26/11/2009, in Viewpoint, by cleo
A short article in Aviation Week and Space Technology caught my eye the other day. “Restructuring U.K. Skies” was the title and it announced that the U.K.’s Civil Aviation Authority (CAA) was beginning the process of defining airspace out to 2030, with industry-wide dialogue to begin in 2010. I counted the number of times the word “airspace” appeared in the item: six. I also counted the number of times the words trajectory based operations appeared. ZERO.
I think it is fair to assume that the editors of Aviation Week would have used the term “trajectory based operation” if they had seen it in the CAA’s press release or the “Airspace for Tomorrow” guidance document. So, its complete lack can be safely taken for an indication of its absence in the CAA’s material.
The United Kingdom is part of SESAR and experts from NATS have been involved in the writing of the SESAR Concept of Operations. So what gives?
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Trajectory Based Operations (TBO) – what is this?
On 16/11/2009, in Buzzwords explained, by steve
We have all grown up with the idea that airspace was the most important single thing aircraft needed. While it is true that aircraft need both air (in which the wings can generate lift) and space (the room to move around in) but airspace? This word has grown over the years and held us hostage to an air traffic management (ATM) paradigm that is one of the main causes of inefficiencies and scarce ATM capacity to-day.
If we look around, we will see plenty of instances where the term “airspace” is used in ways that mask much more essential things, things that need to be considered first and foremost before we think about the space in which those “things” exist.
States have their sovereign airspace, airspace management is an element of the global ICAO ATM operational concept, EUROCONTROL has an Airspace and Navigation Team, and there is the concept of flexible use of airspace… Even the quarterly publication of CANSO, the Civil Air Navigation Services Organization is called “Airspace”. Air traffic control centers have their airspace… Airspace is the magic term we all grew up with and think we understand.
We also tried to solve ATM problems by “improving” airspace. When those efforts did not quite work out the way we had hoped, we pronounced airspace to be a scarce resource almost saying that it was airspace that actually put a limit on how many aircraft there may fly around at any given moment.
In fact, airspace is an almost limitless resort. It appears to be limited only because of the way we use it.
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Military accepts the idea underlying the business trajectory
On 05/11/2009, in SESAR's Palace, by steve
One of the most important paradigm shifts in the SESAR air traffic management operational concept of the future is the move from an airspace based approach to a trajectory based one. It would be a bit lengthy to explain the difference here (there will be a blog article on the subject soon) so let it suffice to say: trajectory based operations are the key to the required predictability and efficiency of the new system.
During the creation of the SESAR Concept of Operations (CONOPS) our military colleagues at first had some difficulty in accepting this new approach. After all, most military operations tend to require a huge piece of real estate that equates to airspace rather than trajectories.
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New directions for Airport Collaborative Decision Making (CDM) – a detailed example
On 13/10/2009, in CDM, by steve
If you have read my article on the New Directions for Airport Collaborative Decision Making (CDM), you will be interested in this narrative description of the envisaged working of the expanded CDM concept. I do strongly recommend that you read the New Directions article first!
The example used is that of a departing flight. It is not a formal use-case as such and it focuses on the most important new features only. The scenario does not aim to be all-encompassing but sufficient detail is provided to enable readers to get a better understanding of the novel applications of CDM. A number of new services are mentioned in this scenario which are in addition to those mentioned in the original article. Their role is self explanatory but if you have any question, please write a comment and I will explain things in more detail.
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New directions for Airport Collaborative Decision Making (CDM)
On 07/10/2009, in CDM, by steve
What exactly is CDM?
Collaborative Decision Making (CDM) is not a new concept. It is being practiced to a certain degree both in the US and in Europe, focus being on en-route in the former and airports in the latter. Mature as the concept may be, surprisingly we still see experts who seem to believe that CDM is little more than a few wise men sitting together and deciding things for the benefit of the community… Little wonder that they see a role for CDM that is strictly limited to the strategic planning phases. They seem to hang on to this view even in the face of actual CDM implementations at some airports (e.g. Munich) which are anything but limited to the strategic phase. So, what is CDM?
The concept of CDM is very simple. Decisions on all levels must be made not in isolation but based on a shared, common view of the state of the ATM network with full awareness of the consequences of the decisions on every aspect of the operation. Collaborative in this context does not necessarily imply people sitting together or working together remotely. A single person can also make a collaborative decision if the decision is based on the shared information provided by the partners and if it takes into account the impact of the decision on those partners and the ATM network as a whole.
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(Before) all else fails… read the Concept! Part 2.
On 23/09/2009, in Buzzwords explained, by steve
What is a net-centric system?
Net-centric, in its most common definition, refers to “participation as a part of a continuously evolving, complex community of people, devices, information and services interconnected by a communications network to optimise resource management and provide superior information on events and conditions needed to empower decision makers.” It will be clear from the definition that “net-centric” does not refer to a network as such. It is a term that covers all elements constituting the environment referred to as “net-centric”.
Exchanges between members of the community are based not on cumbersome individual interfaces and point to point connections but a flexible network paradigm that is never a hindrance to the evolution of the net-centric community. Net-centricity promotes a “many-to-many” exchange of data, enabling a multiplicity of users and applications to make use of the same data which in itself extends way beyond the traditional, predefined and package oriented data set while still being standardized sufficiently to ensure global interoperability. The aim of a net-centric system is to make all data visible, available and usable, when needed and where needed, to accelerate and improve the decision making process.
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Trajectory ownership: dogfight or guiding principle?
On 13/09/2009, in Buzzwords explained, by steve
Few elements of the SESAR Concept of Operations (CONOPS) have generated more controversy than the idea of trajectory ownership did. Regrettably, the controversy still boils. Some experts dismiss the whole thing as a “political dogfight”, others conduct lengthy debates on how trajectory ownership will work (or not work) in daily operations. They are both on the wrong track, revealing a fundamental misunderstanding of what the CONOPS is trying to say. It is time we put the matter out of its misery and recognize trajectory ownership for what it was always meant to be: a strategic guiding principle with a fundamental impact on future air traffic management.
First and foremost, we must realize that, except for the smallest and lightest aircraft, almost all flying machines are in fact business tools of differing sophistication. From rented aircraft to the most modern airliners, they fulfill a mission and are meant to generate revenue for their operators. The Sunday leisure flyers apart, this is true of business jets, crop sprayers, airline transports and even the military.
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Trajectory based operations
On 26/07/2009, in Buzzwords explained, by steve
Trajectory Based Operations (TBO) is a key element of the operational concept of both SESAR and the US NextGen.
But what is TBO? It is definitely more than giving direct clearances and getting rid of route structures is an element, but not the essence, of Trajectory Based Operations.
We will be publishing a post on this exciting subject soon. In the meantime, why not write to us with your understanding of TBO, its perceived advantages or problems. We will strive to answer your issues as part of the forthcoming article.
