When the throttles are advanced for takeoff, the A380’s four engines pump out an incredible 280,000 pounds of thrust, more than any commercial jetliner in history. With heavier future models, such as the freighter, total power will increase to more than 320,000 pounds of thrust. At their ultimate potential, the A380 engines have been designed to collectively generate up to 336,000 pounds of thrust, compared with the 260,000 pounds of a current 747!
The engines that powered the A380 for its maiden flight in 2005 are different from those Airbus first envisaged 15 years earlier. The early studies revolved around the use of A330-sized engines for improved cost, schedule, and development. But as the size of the UHCA family grew beyond 600 to 800 passengers to include a 1,050-seater, the studies had to include six-engine variants to stay within the thrust capabilities of this engine class.
General Electric, Pratt & Whitney, and Rolls-Royce were also, at the time, each in the thick of developing new engines for the Boeing 777. These would prove to be the largest commercial jet engines yet built, and because they were designed for a twin-engine aircraft, they were too big to be used on the multiple-engine UHCA and VLCT designs floating around in the early 1990s.
The key difference between a twin-engine and a four-engine aircraft is that the former are takeoff-thrust limited, while the four-engine designs are climb-thrust limited. The reasoning behind this is simply that a twin must have sufficient power to continue to take off on one engine alone, should it suffer an engine failure on the runway. Individual engine power requirements are therefore not as high in four-engine aircraft, which have more thrust available from the remaining three engines should they suffer a powerplant failure on takeoff.