ICAO’s Chicago Convention placed responsibility for ensuring ATM service provision on States. At the time, this naturally meant that States provided ATM services themselves, designing infrastructure around local requirements in terms of expected traffic. To provide additional capacity, the air navigation service provider (ANSP) could really only add a new sector. As the complexity of traffic (and ATM) grew, sector design became a real art. Just look at the sectorisation between the UK and France – see how well aligned it is with normal traffic flows in and out of London and Paris airports. It has a beauty of its own, but these very specialised sectors come at a price – the diminishing returns of further sectorisation.
Adding a new sector in any airspace is a complex undertaking that can take several years from identifying the need to the final validation and operation. When traffic demand is growing at a steady two to four per cent per annum, as historically it appears to have done, then airspace designers can plan ahead and meet demand.
The simple truth is that growth in demand isn’t really linear. Various crises over the years have led to sharp and dramatic falls in traffic, followed by accelerated growth. The current global pandemic is by far the most dramatic, and hopefully one-off, event. ANSPs had to reduce capacity significantly, and already we are being warned that Summer 2022 is going to be a difficult time because replacing capacity is just as hard as stripping it out.
Sadly, geo-political events like the war in Ukraine are not a one-off. The closeness of Ukraine to the EU and NATO States makes it seem rare, but armed conflict anywhere in the world can move a major air route in Europe from one State to another. We shouldn’t think that volatility is only caused by disasters; on a more temporary basis it can be generated by events such as the Olympics or football World Cup, with a major impact on flows. As can a change in preferred holiday destinations.
The truth is the closer you look the more volatile traffic appears. Global and European traffic forecasts may look like steady growth, but traffic flows themselves might be much more chaotic – even at sector level we can see volatility caused by convective weather. Have a look at Canada’s airspace design for receiving the North Atlantic flows which moves on a daily basis.