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You might assume that the Airbus A380, such a massive aircraft, requires reverse thrust
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on all four engines to help it stop after landing. Surprisingly, the A380 is equipped with reverse thrust on only its two inner engines
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Reverse thrust is a technique used by jet engines to change the direction of airflow
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Instead of expelling air out the back, the engines redirect the air towards the front
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when reverse thrust is activated. This helps slow down the aircraft, particularly on wet runways where the reverse thrust's
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airflow kicks up water. Although reverse thrust aids in decelerating an A380, brakes and spoilers play a more significant
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role in stopping the aircraft. Additionally, A380s land at relatively slow speeds, crossing the landing threshold at
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140 knots and sometimes touching down as slow as 130 knots. Despite being larger and heavier than a Boeing 747-400, the Airbus A380 generally lands
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at a more leisurely pace. When designing the A380, there was a debate about whether reverse thrust should be included
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at all. The aircraft was designed to come to a complete stop using only its brakes
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However, it was ultimately decided to equip two engines with reverse thrust to minimise
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the risk of aquaplaning. The designers concluded that having reverse thrust on all four engines would create more
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problems than it would solve. The first reason the A380 has reverse thrust only on its inner engines is that it's sufficient
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for its needs. Adding more reverse thrust would increase the plane's weight and stress the wing structures
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Equipping a single A380 engine with reverse thrust adds half a tonne of weight
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Considering a fully loaded A380 weighs up to 1,265,000 pounds and is already costly
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to operate, no one wants to burden the aircraft with unnecessary weight
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Another reason for not having reverse thrust on the A380's outer engines is the potential
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hazard it poses on narrower runways. With an 80-metre wingspan, the outer engines may hang close to or over the edge of the runway
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Increased energy output from these engines raises the risk of debris damaging the wings
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and fuselage. Turbulence during landing, especially around the runway's perimeter, can be hazardous
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However, this issue is less concerning during take-off, as the aircraft leaves turbulence
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in its wake. Airbus recommends that A380s operate on runways with a width of 60 metres
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On such a runway, the outboard engines remain well within the boundary
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Airbus also permits A380 operations on runways as narrow as 45 metres, provided there is
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a stabilised surface on the runway's shoulders. It may seem counterintuitive for such a large and heavy aircraft like the A380 to stop so
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efficiently without reverse thrust on all its engines. However, the A380 is a testament to remarkable engineering, capable of landing safely with
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only reverse thrust on its inner engines. Have you ever been on an Airbus A380
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Share your experience with this impressive aircraft in the comments below
