Circular Runway Is Not The Future Of Aviation – It Will Never Take-Off

Last Updated on June 7, 2021 by Vikas Kalwani

You might have seen a concept video of a circular runway going viral on social media. This new radical airport concept was proposed by the Dutch Engineer Henk Hesselink of the Netherlands Aerospace Centre.

He called his project The Endless Runway project. In his research paper, Henk proposed to construct circular runways with a diameter of approximately 3.5 km around the airport terminal.

Advantages of Circular Runway Airport

1. This new circular runway concept would take up only one-third of the space of a conventional airport.
2. Crosswind landings will not be an issue since the plane won’t need to take into account wind direction. The aircraft can simply land at a spot on the curved runway where there is negligible crosswind. Here’s a video compilation of airplanes battling strong crosswind and troublesome wind conditions on a conventional runway.
3. The aircraft could be routed away from residential areas during takeoff and landing because of the circular track. Air traffic can also be avoided if we go for a round runway.
4. On a straight runway, only one airplane can land or takeoff at one time. However, multiple aircraft can use the endless runway at the same time resulting in increased airport capacity.

Here’s how the circular airport runway would look like for Paris, Frankfurt, Madrid, and Amsterdam.

The Endless Runway Project indeed looks promising and spectacular in concept videos and on paper but can the endless runway be the future of aviation?

Let’s dive deep into some technical aspects surrounding aviation to understand if the Endless Runway Concept will ever take off?

Disadvantages of Endless Runway

We stated the advantages of the round runway above. It’s time we shift our focus to the real deal. Can this type of a concept really take off? What could be the technical challenges? Will the pros outweigh the cons? Let’s find out. Here’s why I believe the circular runway concept will not be the future of aviation.

Obstacle Clearance Area in the direction of landing & take-off

Traditional runways are straight because, in the landing and take-off direction, there is an obstacle clearance area. In simple words, an obstacle clearance area is a region some distance away in the line of the runway on both sides that is free from obstacles like trees, buildings, mountains, etc.

Airplanes need this region so as maintain a decent approach profile during landing (when they are flying the instrument approach). As a pilot, when we take off, we absolutely want the area ahead of us to be free from obstacles.

With circular runways, we won’t have a fixed landing and take-off spot. Hence, in order to have that obstacle clearance area, we need to demolish the obstacles all around the circular runway. Can we really afford that?

If the obstacle clearance area is not the same for each degree of the 360 degrees of the runway, there will be different performance calculations for each degree.

Problems with Aircraft Handling after an Engine Failure

Once in a while, engine failures do happen. When an engine fails, the working engine turns the airplane towards the failed engine.

With circular runways, there will be an extreme problem with aircraft handling if one of the engines fails just after takeoff. This is on account of the two forces acting simultaneously – the centrifugal force due to the circular motion of the plane and the force exerted by the working engine (which will turn the aircraft towards the dead engine).

On account of these two forces, it will be extremely difficult for pilots to have the aircraft under control if an engine fails after takeoff on a round runway.

Speeding Aircraft on a Slippery Circular Runway

The speed of an airplane (say Boeing 737) when it lands and takes off is comparable to the maximum speed of a Formula1 race car. Pilots do a great job at such high speeds even when the runway is slippery and wet.

Let’s take the case of a wet and slippery circular runway. Do you really think handling the aircraft will be easy at speeds in excess of 300 km/hr on a wet runway that is circular?

Life is not a video game!

Circular runways will not be safe for landings and take-offs, especially during rainy, snowy, and stormy weather conditions.

Wingtip clearance on account of Banking

Since the outer edge of the circular runway will be banked, the aircraft will face the problem of wingtip clearance. The wingtips and engines on the outer edge of the banked runway will be more closer to the ground when compared to the wingtips and engines on the inner edge.

On account of uneven and reduced wingtip clearances, pilots will need automated support for takeoffs and landings. There could be changes in aircraft design as well.

Moreover, on account of the banked circular runway, an aircraft will need to land faster than normal to avoid a stall.

Changes in Holding Patterns of Adjacent Airports

Let’s assume one airport ditches the traditional runway and alters its airport infrastructure according to the endless runway concept.

Have you wondered how this will affect the air traffic of adjacent airports?

If one airport switches to a circular runway, then neighboring airports will have to change their holding patterns. A holding pattern is a flight path (generally oval) followed by the plane that awaits further clearance.

Moreover, they will need to switch to circular runways as well.

Conclusion

We focused on the advantages of the circular runway concept and its disadvantages. The concept looks good on paper, it is a futuristic concept. However, circular runways will never be the future of aviation. The technical challenges outweigh the advantages. 

I really like the concept though.