Birth of the jumbo
“If you build it, I’ll buy it.”—“If you buy it, we’ll build it.” This brief exchange between Pan Am founder Juan Trippe and Boeing chief Bill Allen transpired in the mid-1960s, just at the start of the widebody era. At that time, long-haul routes were served by the Boeing 707 and Douglas DC-8: quad jet aircraft with a fuselage diameter that permitted six seats per row, three on either side of the aisle.
With passenger volume increasing rapidly, it was only a matter of time before this design would become too small. Douglas responded to the airlines’ requests for a larger aircraft by extending the DC-8 into the “Super Sixties” series. Boeing’s 707 sat too low to the ground to pursue this approach, which is why it decided to completely redesign the aircraft. Juan Trippe was only too happy to agree—the charismatic and unconventional head of Pan Am had searched long and hard for a revolutionary solution and had little interest in one that provided only a small increase in passenger capacity.
At this time, it was widely assumed that passenger air transport would soon be dominated by supersonic aircraft, such as the British-French Concorde or Boeing’s planned 2707. This meant that any subsonic aircraft had to be able to double as a freighter. In redesigning the 707, Boeing based the plans on a military transport concept that lost the contract to Lockheed’s C-5 Galaxy, developed in the mid 1960s. The cockpit was moved “upstairs” to make way for a gigantic nose cargo door for freight, giving the Boeing 747, soon nicknamed “jumbo jet”, its distinctive hump.
The C-5 Galaxy itself also played a key role in the “birth” of widebody passenger jets (sometimes referred to as twin-aisle aircraft). For this aircraft, GE Aviation and Pratt & Whitney designed completely new turbofan engines with a high bypass ratio. These laid the groundwork for the later CF6 and JT9D commercial engines, whose performance made the construction of the jumbo jet and subsequent widebody aircraft possible in the first place.
Jets for high-volume routes
On January 22, 1970, the first scheduled flight of a Pan Am jumbo jet took off from New York for London—one day later than planned. This delay was symptomatic of the difficulties faced by Boeing as it attempted to pioneer the widebody passenger jet. Much more serious than the initial unreliability of the JT9D engines, however, was the oil crisis of the early 1970s and the undeniable fact that, for many routes, the jumbo jet was simply too large.
Yet even the somewhat smaller widebody models that competitors launched on the market at virtually the same time also struggled. In the mid-1960s, American Airlines executive Frank Kolk wrote a strategy paper in which he established the requirements for a future widebody jet for high-volume medium-haul routes: a carrying capacity of about 300 passengers and powered by just two engines. However, McDonnell Douglas and Lockheed decided to give their new jets three engines. The DC-10 was put into service on August 5, 1971, followed almost a year later by the L-1011 “TriStar” on April 26, 1972. Both of these were initially used predominantly on U.S. domestic routes, and later branched out into intercontinental travel. As they did so, they increasingly replaced the smaller quad-jet single-aisle model; it was substantially less profitable due to its lower carrying capacity, and its low-bypass engines made it a good deal louder.
Modern widebody aircraft
Boeing 787-8 Dreamliner First flight: 2009; length: 56.7 meters; wingspan/width: 60.1 meters
Boeing 787-8 Dreamliner
Twin Aisle Widebody
approx. 220 tons take-off weight
Boeing 777-300 First flight: 1997; length: 73.8 meters; wingspan/width: 60.9 meters
Twin Aisle Widebody
approx. 300 tons take-off weight
Boeing 747-8 First flight: 2011; length: 76.3 meters; wingspan/width: 68.5 meters
Twin Aisle Widebody,
approx. 450 tons take-off weight
Airbus A380 First flight: 2005; length: 72.7 meters; wingspan/width: 79.8 meters
Twin Aisle Widebody, double-deck
approx. 575 tons take-off weight
Crossing the Atlantic on two engines
Twin-jet aircraft of the sort Kolk envisioned were then indeed built—not by one of the established U.S. manufacturers, but by a newcomer from the other side of the Atlantic. The A300 was developed within the Airbus consortium led by France and Germany with British and eventually Spanish involvement. It took off on its maiden flight on October 28, 1972 and was in regular service as of May 1974.
Hardly anyone at the time could have guessed what fundamental changes the arrival of this European jet would trigger in the industry. For one thing, Boeing and its peers were confronted with a competitor that conquered half the global market within about four decades and also proved to be a deciding factor in Lockheed’s withdrawal from the commercial market and McDonnell Douglas’s being forced to seek refuge in a merger with Boeing. For another, the A310 (based on the A300) and, to an even greater extent, the Boeing 767, which appeared on the market at roughly the same time, made it possible to fly long-haul routes with twin-jet aircraft. Airlines could now offer nonstop connections outside of the major aviation hubs.
THE FIVE LARGEST AIR PASSENGER HUBS IN THE WORLD (NUMBER OF PASSENGERS)
Dubai, UAE (DXB)
London, GB (LHR)
Hong Kong, HK (HKG)
Paris, FR (CDG)
Amsterdam, NL (AMS)
International passenger traffic The figures comprise all passengers boarding and disembarking at the respective airport over the period from April 2014 to April 2015.
THE FIVE LARGEST AIR CARGO HUBS IN THE WORLD (MEASURED IN TONS)
Hong Kong, HK (HKG)
Incheon, KR (ICN)
Dubai, VAE (DXB)
Shanghai, CN (PVG)
Taipeh, TW (TPE)
International freight traffic The volumes comprise the total freight and airmail loaded and unloaded at the respective airport in tons during the month of April 2015.
Source: Airports Council International, July 2015
Measured in flight time, the distance that a twin-engine jet is allowed to be from an alternative airport in the case of engine failure increased steadily, thanks primarily to the major boost in the reliability of the modern turbofan engines. The first transatlantic flights were flown with the A310 and B767 in the mid-1980s; today it is possible to receive ETOPS (extended-range twin-engine operational performance standards) certification for five hours and longer, depending on the type of aircraft. This means that even jets equipped with only two engines can fly virtually any route in the world without making a detour.
WIDEBODY AIRCRAFT AND ENGINES FROM 1960S TO TODAY
Bigger and farther
But the engines didn’t just get more reliable; they also became more powerful, so that the aircraft size at which two engines were no longer sufficient kept getting bigger and bigger. Twin-jet models were soon able to hold their own when it came to range, as well. In the early 1990s, Airbus put the quad-jet A340, which can theoretically transport up to 440 passengers, on the market beside the A330. The latter was just as large but had only two engines, and actually sold much better. Another major twin-engine success was Boeing’s “Triple Seven,” which made its debut in the mid-1990s. In the engines they developed for the aircraft, GE Aviation, Pratt & Whitney, and Rolls-Royce pushed dimensions and performance to hitherto unseen levels.
This trend became particularly evident when new versions of the A340 and Boeing 777 were launched on the market at the start of the millennium. In terms of range and passenger capacity, they were clearly designed as successors to previous 747 models. The twin-engine 777-200LR and -300ER performed as well as or better than the A340-500 and -600, and did so at lower cost. Airbus took this lesson and implemented it in the A350 XWB; since then, models smaller than the A380 are also based solely on a twin-engine design.
Where to next?
As twin-engine aircraft become ever more efficient—seat kilometer costs of the A350-1000 and Boeing 777-9 models currently in development are expected to match those of the A380—it raises an important question: Are aircraft like the A380 or the only slightly smaller 747-8, the latest jumbo jet, even necessary? “Sales of widebody aircraft with two decks are not going as well as they were forecast to ten years ago,” states Dr. Marc Le Dilosquer, Director, Market Analysis at MTU Aero Engines. In fact, airlines are currently holding off on new orders, although this may also have to do with changes in the market environment. The rapid growth of Persian Gulf airlines has shifted traffic flows; passengers wishing to travel from Europe to destinations in the Asia-Pacific region no longer automatically fly via Hong Kong, Singapore or Bangkok. They are also no longer limited to Qantas Airways, Singapore Airlines, Thai Airways International or Cathay Pacific, carriers that dominated these routes for decades. But if Airbus equips the A380 with new engines, thus regaining the former operating cost advantage over the smaller twinjets, then the A380’s biggest customer, Emirates, will purchase still more of the world’s largest passenger airliner.
At any rate, John Leahy, Head of Sales at Airbus, remains confident. The number of mega-cities, which Airbus defines as cities that see more than 10,000 passengers a day on long-haul flights, is expected to nearly double over the next 20 years from 47 today to 91. Leahy makes a clear case that this will create demand for aircraft like the A380. But Randy Tinseth, Vice President Marketing at Boeing Commercial Airplanes, counters this with arguments that are just as convincing. In the past ten years, the number of flights to places such as Tokyo’s Haneda and Narita Airports or Seoul’s Incheon International—in other words, airports in precisely such mega-cities—has grown between 26 and 33 percent. At the same time, the number of available seats declined at a double-digit rate. Tinseth concludes that the market is demanding higher frequency rather than larger aircraft.
That the lion’s share of long-haul passenger routes will be handled in the future by twin-jet aircraft might indeed be indisputable. However, it’s still too soon to bid the A380 adieu. Don’t forget that the jumbo jet didn’t become the best seller it is remembered as today until the completely redesigned 747-400 version went on the market—more than 20 years after the first prototype made its maiden flight.
WIDEBODY AIRCRAFT AND ENGINES FROM 1960S TO TODAY
Inside MTU Widebody engine expertise at MTU Aero Engines
For more than four decades, MTU Aero Engines has actively participated in developing and manufacturing widebody engines, and during that time, its role has only increased in importance. Its story began in the early 1970s with GE Aviation CF6, one of the most successful turbofan engines of all time. Now used in the A330, B747 and MD-11, to name just a few, the engine features MTU parts in its turbine and compressor.
GE competitor Pratt & Whitney is involved in production of the PW4000, one of three engines for the original versions of the Boeing 777. MTU was able to land the contract for developing the low-pressure turbine, which it manufactures to a large extent in house.
For the A380’s engine, the GP7200, MTU developed and now manufactures the low-pressure turbine and the turbine center frame. In addition, MTU produces components for the engine’s high-pressure turbine, putting its program share at a proud 22.5 percent (see “The GP7000 engine for the A380”).
MTU develops and builds the turbine center frame for GE’s GEnx engine (used in Boeing’s 787 and 747-8) and the GE9X, which will power Boeing’s new long-haul models 777-8 and 777-9 (see “In the middle: The turbine center frame for large aircraft engines”).
But MTU does more than just develop and manufacture widebody engines—these also currently account for about a third of all overhaul work at MTU Maintenance in Hannover. The CF6 is the most important product at the moment and is expected to remain so for some time, according to Norbert Möck, Director GE Programs at MTU Maintenance. The halls in Hannover have also already seen more specimens than planned of the GE90, which was added to the portfolio three years ago.