There is no hiding the fact that the Airbus A380 is an enormous plane. Its sheer size, which, to many, is its greatest appeal, means that, correspondingly, it generates more wake turbulence than smaller aircraft. This means that planes flying immediately after A380s must be carefully sequenced to avoid such turbulence. But how much space exactly is needed?
What is wake turbulence?
Planes disturb the air as they fly through it, owing to their size and speed. Their presence causes turbulent air to form behind them, which can become dangerous for other aircraft if they are caught up in it. Multiple components make up the phenomenon as a whole.
One such component is known as jetwash, and is a more immediate aspect of the phenomenon. The term refers to the gases themselves that collect in the area behind an aircraft having been propelled from its engine(s). This tends to occur on a more short-term basis, although the turbulence itself that arises as a result can be more violent.
Meanwhile, wingtip vortices tend to remain present for a longer time, which can last for several minutes after the aircraft passes. These arise when a wing generates lift, with low pressure above it drawing air from below the wing to the area above. This produces turbulent wingtip vortices, which, as seen below, can be a rather more visible phenomenon.
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How much space is needed behind A380s?
Being the largest passenger-carrying aircraft in the world, the Airbus A380 generates more wake turbulence than other, smaller designs. As a result, this must be factored in by air traffic controllers when they are sequencing aircraft flying immediately behind it.
According to Skybrary, there are various time and distance requirements depending on the size of the aircraft following the A380. In terms of time, it states that ‘medium’ aircraft must land at least three minutes behind the double-decker, with ‘light’ models requiring four. Meanwhile, light and medium planes must take off at least three or four minutes (runway-dependent) after an A380 has departed. For ‘heavy‘ aircraft, this is two minutes.
In terms of distance, Skybrary lists the minimum required separation between an A380 and a following light aircraft to be as much as 14.8 km (8 NM). Meanwhile, medium aircraft require 13 km (7 NM) of separation, and heavies need 11.1km (6 NM). These distances are reportedly required in both the departure and approach phases of a given flight.
Affects on airport capacity
For airports where the A380 is a common fixture, the required distances can impact their capacity. This is because they can limit the number of aircraft that can arrive and depart over a given period if several A380s pass through during this time. Of course, with Emirates being the largest A380 operator, its Dubai International (DXB) hub is at risk of this.
However, the airport has recently been able to increase its capacity by implementing new separation procedures. Eurocontrol, Emirates, and flydubai have partaken in an Enhanced Wake-Turbulence Separation program, with studies dating back as far as 2013.
The result is the new separation procedures, known as RECAT. According to Air Insight, the new system can allow up to three extra arrivals and six extra departures every hour during peak periods. As traffic increases with the industry looking to recover from the effects of the ongoing coronavirus pandemic, this extra capacity will be very useful indeed.
Have you ever been on a flight that has taken off straight after an A380 and subsequently needed to wait a little longer? Let us know your thoughts and experiences in the comments.