An incredible video of an Emirates A380 superjumbo landing in crosswinds has gone viral, clocking up 10 million views in less than a week.
The flight, which touched down at Dusseldorf airport on a flight from Dubai last Thursday, was buffeted by winds as it came into land as major storms hit the country.
The action really starts after the A380 hits the tarmac, with the world's largest commercial aircraft swerving violently as the pilots try to keep it aligned with the runway.
Anyone who has flown on an A380 superjumbo will have noticed it feels like the aircraft takes a long time to take off once it starts down the runway. And it's true - an A380 requires a longer runway than many other aircraft.
Getting the right runway for the right aircraft is crucial. On January 21, 2017, a Tigerair A320 en route to Brisbane was taxiing for departure at Cairns Airport and lined up for takeoff via the wrong taxiway, B4 instead of B5. Since taxiway B4 is considerably further down the runway, a takeoff from there would have shortened the available runway by 410 metres. Before that could happen Cairns air traffic control spotted the mistake and sent the pilot to taxiway B5.
Different aircraft types have different power/weight ratios that determine how quickly they can become airborne, and how much runway they need. The takeoff runway length requirement for the Airbus A380-800 is 2900 metres. For a Boeing 747-8 the figure is 3050 metres. For a 777-200, it's 2440 metres.
These are minimum requirements that apply to an aircraft at Maximum Certified Takeoff Weight (MTOW), taking off at sea level under ISA conditions, i.e. a temperature of 15 degrees, but there are several factors that determine when an aircraft achieves sufficient airspeed for takeoff, and therefore how much runway it needs. Even the same aircraft departing from the same airport on the same routing with an identical load will leave the runway at a different point on consecutive days.
As well as aircraft type, weight, wind strength and direction and altitude are factors that play into the runway length an aircraft needs for takeoff. Higher altitude equals less dense air, and therefore less lift and greater takeoff distance required.
According to the performance chart for the Boeing 737-800, at sea level under ISA conditions with a takeoff weight of 140,000lbs, the runway length requirement is 1510 metres. At an altitude of 1220 metres that same 737-800, requires 1830 metres. At 2440 metres that figure is 2470 metres. Denver International Airport's 16R/34L runway measures 4877 metres, the longest commercial runway in North America. The airport's altitude of 1665 metres is the reason why.
Temperature also comes into the equation. Hot air is less dense and this affects the output of the engines as well as the aircraft's aerodynamic capabilities, increasing the required runway distance.
For that reason runways at Middle Eastern airports need to be far longer than those in cooler climates. The longer of the two runways at Hamad International Airport in Doha, Qatar's capital, is 4850 metres. Dubai International Airport's main runway is 4447 metres. The longest runway at London's Heathrow is 3902 metres. The main runway at Melbourne's Tullamarine is 3657 metres while the runway at Iceland's Keflavik International Airport is relatively short at 3065 metres yet it's used as an emergency landing runway for large aircraft on trans-Atlantic routes.
As temperatures spike with global warming, flight delays caused by high temperatures could become a more common feature of air travel. During the intense heatwave experienced in western states of the US over the summer of 2017, extreme temperatures made it difficult to generate the required lift for planes to take off, leading to flight delays.
As well as the individual factors that determine how much runway a specific aircraft needs under specific conditions there are overarching regulations governing the length of runway from which an aircraft type is authorised to operate. The Federal Aviation Regulations (FAR) takeoff field length applies inherent safety features to account for engine failure at critical times during takeoff.
If an engine fails during the takeoff roll before or at the point where the aircraft reaches decision speed, known as V1, the pilot can continue the takeoff on the remaining engine or engines, or shut them down and apply full braking. In the first case the length of the runway must be sufficient for the aircraft to take off with one engine down from V1 and achieve an altitude of 11 metres before the end of the runway, or, in the second case, to come to a complete stop on the runway.
It's surprising just how many runways and airports there are around the world capable of handling even the largest passenger aircraft. According to Airbus, the A380 lands regularly at more than 140 airports. Including diversionary airports, where the aircraft could land in case of an emergency, the total figure comes to more than 500.
A recent example happened at the end of September 2017 when an engine disintegrated on Air France A380 flying from Paris to Los Angeles. The pilot made an emergency landing at Goose Bay in Canada's Newfoundland, which has a runway measuring 3368 metres, used in emergencies for trans-Atlantic flights. Goose Bay is a Canadian Forces Base that goes by the name of Happy Valley, a fact probably not lost on passengers and crew of the stricken Air France jet.
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