CDM in Aviation - Just Two Ways of Doing it !

It′s surely no surprise I am writing about the adoption of CDM within the Aviation world ! Good or bad news, I don′t plan to stop, while I believe all I can say is what air transport stakeholders worldwide need to hear.

It sounds a bit arrogant, I know, but I take that risk. ?

For justifiable reasons, back in 2012, ICAO decided to use CDM acronym, to characterize it proposed Collaborative Air Traffic Flow Management concept, for the handling of highly congested airspaces. It made perfect sense.

Unfortunately, that led the entire aviation world to believe the growing unbalance between air transport demand and capacity, could be resolved by means of “collaboration and information sharing”, rather than stakeholders accepting individual/immediate sacrifices for the sake of collective/long term benefits.

The end result of it, is that 16 years later, by just taking a glance on the various CDM based initiatives, proliferating around the world, I intend to demonstrate there are only two ways of doing CDM in Aviation.

Getting started

Let′s make it simpler, by going back to basics, using the analogy with Vehicle Urban Traffic, at busiest cities, around the world.

Capacity Increase Initiatives

Initiatives, such a synchronization of traffic lights, efficient signage and use of reversible lanes, actually increase the capacity of ground′s physic infrastructure!

No doubts about it!

Demand vs Capacity Balance initiatives

What about License Plate Driving Restrictions ?

Do they increase?the capacity of ground′s physical infrastructure ?

No, they don′t! But….

• they limit users′ right to access city′s ground infrastructure
• they prevent demand in excess of the existing capacity, led to unnecessary congestion (and fuel burn)
• they cause travel times to become more predictable, as traffic jams are minimized

So, while it′s fair to say although License Plate Driving Restrictions do have a value, they are way more complex and painful than “collaborate and share information”. But if I want to present it nicely, I can say all you need is to Collaborate (adhering to the Driving Restriction rule) and Share Information (your car′s license plate).

Much easier to swallow, isn′t it ?

Well, it′s not different with aviation and if you have been able to follow this far, you′ve already come halfway !

Let′s have a look at the two basic steps of CDM in Aviation !

Please ignore any CDM based conops you have attempted to learn, so far. Don′t follow the Bible, unless you believe in God !

CDM Step 1 (Airspace Sequencing)

For Regions where a global consensus was reached that rational fuel consumption should take priority over take off punctuality, ICAO has proposed the Collaborative ATFM and GDP (Ground Delay Program) measure, by which flights beyond airspace capacity should be held on the ground, for as long as needed, to balance Demand vs Capacity.

That′s what CTOTs (Calculated Takeoff Times) do !

Those who understood License Plate Driving Restriction, will easily recognize what GDP is, and what is takes to be accepted.

A bit more complex than simply “collaborate and share information” !

That′s just the first level of sacrifice, airlines need to accept, if they consciously opt to go for CDM in Aviation. Takeoff punctuality will be just as good as it can be, for achieving maximum fuel efficiency (and predictability).

Europeans have accepted it with Eurocontrol ATFCM (Air Traffic Flow and Capacity Management) and so have North Americans, with the FAA TMFS (Traffic Flow Management System)

CDM Step 2 (Pushback Sequencing)

In some cases, CDM′s first level of sacrifice (Airspace Sequencing) may not be sufficient, for the level of existing Demand vs Capacity unbalance and the proliferation of CTOTs may result in flights reaching the holding point for takeoff, prior to CTOT. They need to wait, and so do all flights behind, in the takeoff sequence.

That′s when all stakeholders need to jointly accept one more level of sacrifice, which will squeeze their operational flexibility, by limiting the push-back pre-approved time of all flights, within a 10-minute time window (TSAT -5/+5), which will be as viable as their TOBT have been accurately predicted

TOBT: Target Off-Block Time

TSAT: Target Start-up Approval Time

That′s when airlines will probably miss initiatives, they have historically ignored – such as dedicated Apron Management Service and Common-use Surface Surveillance, which would enable them to determine more accurate TOBTs (Target Off-Block Times).

The important thing though is that, regardless of the acronym, used by the developer of each CDM based conops, that′s what CDM in aviation is - a process by which, increasing levels of interferences, in airlines′ flight intentions are introduced, with a view to ensure maximum fuel efficiency, in detriment of punctuality expectations.

While Airspace Sequencing - via GDP assigns CTOTs to some flights, Pushback Sequencing enforces TSAT (+/-5) to all flights !

One more level of sacrifice, for the sake of maximum fuel efficiency.

Currently, numerous principles, conceptual elements and technologies are proposed to help stakeholders in two ways:

• Increase airport capacity, with no CDM inherent interference in airlines′ flight intentions
• Help those who consciously accept CDM sacrifices, assuming their efforts to increase capacity, have been insufficient to reach their desired level of operation performance

All such principles, conceptual elements and technologies, have been grouped and implemented in different ways, as required to meet regional needs and possibilities.

Each one with a different acronym and/or a different version.

However, whichever the case is, given that, CDM adoption is not mandatory, at this stage, I am convinced you will agree with me there are only two ways of implementing CDM in Aviation.

KNOWING what you are doing... or NOT KNOWING what you are doing !?

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