4 Engines

The only commercial airliner with 4 engines that is in production today is the Boeing 747. Other 4 engine aircraft that can be seen are the Airbus A340 and the double decker Airbus A380. Due to their inefficiency the numbers of these planes in service will continue to decline over the next decade. Place your mouse over the red links below to see the differences highlighted in the illustrations below.

Background

The Boeing 747 entered service in 1970 and became popular with both passenger and cargo airlines. There are no airlines in the U.S. currently flying the passenger version of the 747 while freighters continue to be flown by UPS, Atlas, Kalitta Air, and others. The largest operators of passenger 747s are Lufthansa, Korean Air, and Air China. 1,555 Boeing 747s have been built in the last 50 years and 455 remain in use today. As of August 2020 there are only 12 outstanding orders for the 747-8 and production will end when those are delivered in the next few years.
The Airbus A340 is a 4-engine version of the A330 designed to compete against Boeing’s long range widebody aircraft such as the 747. It entered service in 1993 and production ended in 2011. No airlines in North America operate the A340. Of the 380 built, 128 remain in service with Lufthansa, Iberia, and Swiss International as the largest operators. There are also more than two dozen of these jets privately owned around the world and outfitted for executive travel.
The Airbus A380 is a widebody double deck aircraft that entered service in 2007. The largest operator is Emirates but due to a lack of new orders, when Emirates switched future aircraft orders to the A350 Airbus decided to end production on the A380 when the final orders are completed by early 2021. The economics of today’s commercial aviation market make these planes too expensive to operate profitably. As of September 2020 the only airlines flying them are Emirates and China Southern due to the COVID-19 pandemic, and some are even being sold for scrap despite being only 10 years old. A large number of A380s remain in storage and it is unclear when and if they will fly again. While Airbus did not market a freighter version of the A380, there is a new aftermarket modification program that could see a number of them converted to freighters over the next few years.

What to Look For

Boeing 747 and Airbus A340

The 747 is the only aircraft with an upper deck over the front section only.

Only one version of the 747 has winglets (the -400 series, produced from 1989 to 2008) while all A340s have them.

The 747 was available from the factory in a freighter version as well as passenger-to-freighter conversions while the A340 was not. A 747 freighter will have 3 windows on the upper deck for the crew rest seats. There are no windows on the main deck of a factory-built 747 freighter while the converted ones will still have outlines where the windows were and they were plugged.

There are some differences that can distinguish a current version, the 747-8, from the older 747-400. The 747-8 is 19 feet longer and it does not have winglets but rather a curved wingtip similar to the Boeing 787. In addition, the 747-8’s engine housings have sawtooth shapes called chevrons on the trailing edge; they’re the same engines found on the 787. The 747-8 can be seen in both freighter and passenger configurations.

There are 4 versions of the A340 and the only difference visually is length. All A340s will have 4 exit doors per side but the A340-600 adds an emergency exit over the wing on each side. The A340-600 (shown here) was the longest airliner in production until the 747-8 was introduced.

The 747 is the only aircraft with an upper deck over the front section.