Going round in circles? A set of objections to the circular runway idea

Image credit: The Endless Runway

Recently I read an article regarding a study about circular runways in which were listed all the benefits of such a solution.

To be honest I don’t see how these circular runways could be better than a standard ‘normal’ runway, currently in use and solve the problems that they claim to solve.

There are many aspects both on the “air” and on the “ground” side of an airport that leave me with many doubts and questions as to why circular runways can offer any particular step in the right direction.

Here are my reasons for why I believe circular runways to represent an unnecessary project we need not pursue.

• The circular runways project strives for optimal wind at take-off, but the exact point where the plane will rotate remains undetermined. Basically circular runways are introducing more variables while trying to solve a problem that is already dealt with by regulations, procedures and techniques.
• When trying to land upwind, you have to change wind angle as soon as you land which itself presents a significant challenge for pilots.
• The circular runways project aims to secure more space for take-offs and landings but there effectively remains only one useful runway – the one going upwind – unless you were to build an inner and outer ring. Even better, only a circular sector of few degrees could be used, due to wind constrictions.
• Circular runways do not save any fuel burn for approaching planes because they still have to vector to where they wish to land upwind. Besides, planes aren’t burning that much additional fuel flying around to downwind as they descend. But they’d still have to land upwind and it would be more challenging and dangerous because unless the plane touches down right where the circular runway is pointed upwind then there will be a slight crosswind.
• Turning is the last thing you want to be doing when flying as slow as landing speed, which is near stall speed, due to the inboard wing being that which stalls first, so your planes will be crashing before they get to the runway.
• How do we build the ILS infrastructure around this kind of runaway? And what about airport landing lights?
• How do we re-programme the aircraft systems for a CATIII approach and landing on this roulette?

Many questions remain unanswered in my view.

Some arguments against the “environmentally friendly” and “efficient” nature of circular runways:

• Circular runways have a diameter of 3500 mt, which means that a circular runway of 10 km (almost 3 times a normal runway) but only a circular sector of few degrees, could be used due to wind constrictions.
• Circular runways occupy a surface on which could be built 4 or more runways up to 3500 mt long in the pattern of a ‘#’ or ‘X’ which would enable the use of two runways at the same time: one only for take-offs and one only for landings.
• All limitations around the airport to building constructions and noise pollution that on normal runways have an axial symmetry, for circular runways would have a radial symmetry, thus involving a larger footprint on the ground.
• All the services (railways, roads, buses, taxies…) would have to be placed underground which itself would be highly costly, polluting in the construction process and present a block to future expansion – even for planes (parking areas) and passengers (terminals) infrastructures constrained within the circle.

Moving forward

I think in order to solve aviation’s future  environmental challenges and mobility problems in the coming decades, we can collectively find better solutions that apply innovative technologies to aircraft configurations and capabilities, by advancing wing technology, aerodynamics and flight dynamics, in-engine technologies to convert stored energy into a fuel-efficient future and finally quiet thrust for the journeys of tomorrow.