There are three well known commercial passenger aircraft that have four engines. The famous Boeing 747, the huge Airbus A380 and the versatile A340. Why did Airbus build two quad-jet aircraft, and which is best? Let’s find out.
Why do some planes have four engines?
Back at the beginning of aviation, many jet aircraft had four engines. This was to help increase the flying power of the aircraft (allowing it to carry more weight) and to factor in redundancy. For journeys far away from any airport (or in the case of the Pacific Ocean, away from any land full stop!) four engines meant there were still three to fly on if one went wrong.
Famous quad-jet aircraft include:
- De Havilland Comet, the world’s first commercial jetliner.
- The Concorde (with four underwing mounted engines)
- The game-changer Boeing 747
And the Airbus A380 and Airbus A340.
However, today only the freight version of the Boeing 747-8 is still in production. The A380 and A340 have since been discontinued and replaced by twin-engine variants. This is due to a variety of factors, such as the approval of twin-jet aircraft to fly more remote routes away from diversion airports and a focus on fuel efficiency.
The Airbus A380 vs the Airbus A340
So how do the two quad-jets stack up compared to one another? Let’s explore.
- The A380-800 could carry 555 passengers in a three-class configuration. Specifically listed as 22 first-class passengers, 96 business class passengers and 437 economy passengers or a massive 853 passengers in an all-economy configuration. It has a range of 14,800 km / 8,000 nm.
- The A340-600, on the other hand, can carry 380 passengers in a three-class configuration. Specifically listed as 12 first-class passengers, 54 business class passengers and 314 economy passengers. In an all-economy configuration, the aircraft could carry 440 passengers. The aircraft has a range of 13,980 km / 7,550 nmi.
On paper, the Airbus A380-800 has an equal range and can carry plenty more passengers. This makes it ideal for popular routes in the 8-12 hour range as the fuel burn per seat cost would be significantly lower than the A340.
In terms of range, both aircraft match relatively close, with the A380 having the advantage of newer technology at the time of its development. If Airbus were to ever build the A340neo, then it is likely that this range would be massively extended. Also on that point, some suggest that in fact the A350 is the spiritual successor of the A340 as a twin-jet, and has all the improvements we would see in an A340neo.
Which is best?
The A380 was designed for a very specific purpose. It was created to fly between hub airports and carry as many passengers as possible. In this role, it succeeds. However, outside of this deployment it’s statistics and trumped by other aircraft (especially those of the twin-jet variety).
Compared to the A340 series, the A380 comes up short. With the A380 requiring special airport modifications to land at, the having a capacity that is so huge it is difficult to fill up and be profitable, the smaller A340 is simply a more attractive aircraft for airlines.
What do you think? Let us know in the comments.