The Boeing 767

Commercial aircraft are the result of the airline requirements which shape them, attempting to fulfill, as completely and cost-effectively as possible, the particular combination of mission goals. For airliner-type aircraft, these include two primary parameters: payload, comprised of passengers, baggage, cargo, and mail, and range, which enables a carrier to offer nonstop service between specific city pairs.

Aircraft configurations are, in essence, design solutions to intended operating missions and hence vary according to fuselage length and width; wingspan, planform, and sweepback; engine type, thrust, and mounting; and horizontal and vertical tail location and size.

In the late 1970s, passenger demand had begun to eclipse the capacity of the Boeing 727, which had accommodated a maximum of 131 single-class, high-density passengers in its initial, short-fueselage -100 series and 189 in its stretched, -200 version.

Seeking to replace this venerable design on one-stop transcontinental routes with a higher-capacity tri-jet, Boeing had considered several replacements by stretching the 727-200’s fuselage, remounting two of the three engines to the wing underside, and ultimately eliminating the third engine in the vertical tail. The result, a low-wing, twin-engined, single-aisle airliner based upon the performance specifications submitted by American Airlines, Delta, and United, had been designated the 757. During this time, however, passenger acceptance of widebody aircraft had been overwhelming and many carriers had sought such a cabin cross-section on medium- as well as traditionally long-range route sectors. As a result, passenger capacity per aircraft had begun to decrease, from the 500 of the quad-engined Boeing 747, to the 350 of the tri-engined Lockheed L-1011 and McDonnell-Douglas DC-10, to the 225 of the twin-engined Airbus A-300.

With the margin between the maximum capacities of the 727-200 and the Airbus A-300 beginning to converge, many airlines had expressed interest in a small widebody which could accommodate the median of the two. The result, the 767, featured greater range and wider-cabin comfort with seven-abreast, dual-aisle coach seating for about 200, becoming the first (and thus far only) commercial airliner to deviate from the standard wide body fuselage width of previous Boeing, Lockheed, McDonnell-Douglas, and Airbus aircraft. The chosen width had offered both advantages and disadvantages. Of the advantages, it had featured less fuselage cross section-generated drag and increased cabin comfort, with most passenger seats either on the window or the aisle. Of the disadvantages, it had not been able to accommodate the now-standard LD-3 container on its lower deck in the traditional paired loading configuration and therefore had required the design of a smaller, specialized LD-2 container.

In January 1978, Boeing had expanded its Everett, Washington, production line, hitherto the sole domain of the 747, to include the new 767 design, and seven months later, on July 14, United Airlines had ordered 30 of the type, officially launching the program. First flying in prototype form on September 26, 1981, at which time orders had been received from 17 customers, the aircraft, in its initial -200 series domestic guise, received its FAA certification with the 44,300 thrust-pound Pratt and Whitney JT9D-7R high bypass ratio turbofan on July 30, 1982. The type entered scheduled service with United the following month on August 19. The aircraft was also certified with the General Electric CF6-80A powerplant on September 8 and this version entered service with Delta Air Lines. A variant with the Rolls Royce RB.211-524 engine, intended for British Airways, had also been offered.

Although initially intended for medium-range operation, the basic airframe had proven ideally suited toward larger-capacity deployment on thin, nonstop transcontinental and intercontinental sectors after being fitted with additional fuel tankage, thus able to replace previous widebody trijets. Dimensionally identical to the basic design, but certified with higher operating weights, the sub-version, designated 767-200ER…for “extended range”…had entered service on March 26, 1984.

The basic 767 fuselage, initially designed for increased capacity “stretchability,” had been lengthened by some 20.1 feet, accommodating 40 additional passengers. Although it had retained the original wingspan, the new version, designated 767-300, had been intended for higher-capacity transcontinental routes and had been first rolled out on January 30, 1986. Certified nine months later in September, it had entered scheduled service on September 25.

Mating the newly-elongated fuselage of the -300 series with the extended range capabilities of the -200ER, Boeing had produced the -300ER with increased-thrust engines, additional fuel capacity, and minor structural strengthening. Recording a 50,000-pound gross weight increase, the 767-300ER, numerically the most popular version with 505 aircraft having been sold, had featured a 2,000-mile range increase, entering scheduled service on February 19, 1988.

The final version, the 767-400ER, had incorporated technology designed for the already-in-service 777-200. Accommodating some 409 single-class passengers in a 21-foot longer fuselage and featuring a 14-foot greater wingspan with highly swept, raked wing tips, the 400,000-pound version had sat on a higher main undercarriage in order to retain take off rotation angles. The aircraft, with a remodeled passenger interior, had closed the gap between its smaller -300 series 767 and its larger 777 design. Although it had offered numerous advancements, it had appeared after most of the market had already ordered previous 767, A-330, and A-340 versions, not entering service until August 20, 2000, and therefore had only been operated by Continental, which had ordered 16, and Delta, which had ordered 21.

All aircraft incorporate several design-shaping characteristics.

The Boeing 767, for example, had replaced the 727 with a larger capacity, widebody design, retaining gate and ramp compatibility at smaller, 727-like airports, and had been optimized for the tri-jet’s one-stop transcontinental routes. Because of parallel 757 development, it had been able to minimize its development costs.

A narrower fuselage cross-section than that used by previous widebody aircraft had resulted in a reduction in parasite drag and a twin-aisle cabin, in which passengers had never been more than one seat away from the window or the aisle. Composite construction had been used in most of the flight surfaces, particularly the fixed wing leading edge panel, the spoilers, the ailerons, the fixed wing trailing edge panel, the undercarriage doors, the elevators, and the rudder, and the airframe had utilized advanced, light-weight aluminum alloy construction.

A supercritical wing, one the aircraft’s key design features, had resulted in a high aspect ratio, an aft-loaded section, the development of more lift for less drag than any previous airfoil, a 22% thicker wing than that used by any previous-decade commercial airliner, a lighter and simpler structure, and more wing-integral fuel tank capacity.

Powered by two high bypass ratio turbofans, in which a higher percentage of the engine’s thrust is produced by the cooler, inner core-bypassing air, it had featured lower specific fuel consumption, a reduced noise footprint, lower maintenance costs, and high reliability.

A two-person cockpit crew, following the trend created by the Airbus A-300, had reduced crew costs, and the aircraft’s common pilot type rating with that of the narrow-body Boeing 757 had ensured greater crew scheduling flexibility to carriers which had operated both types.

Inherent fuselage stretchability and existing wing and tail capability had enabled the manufacturer to offer increased-capacity versions and these, coupled with its extended range twin-engine operations certification, had enabled it to offer a viable DC-10 and L-1011 alternative with one fewer engine and cockpit crew member, significantly reducing operating costs.

Although sales of the Boeing 767 had dwindled by 2008, the type, currently being replaced by Boeing’s own 787, had sold some 950 aircraft of all versions to well over 100 worldwide airlines.

The Boeing 747-400

747-400 Foundation:

Powerplants were the key to commercial aircraft capability, measured by payload, range, and performance, and all were incorporated in the 747-200B when the 63,000 thrust-pound Pratt and Whitney JT9D-7Q became available. First ordered by Northwest Orient, but quickly followed by Braniff, Japan Air Lines, Singapore Airlines, and Avianca, the version, introducing lighter nacelles, offered a two- to three-percent reduction in fuel consumption. Powered by the similarly-rated General Electric CF6-50E and Rolls Royce RB.211-524D turbofans, the aircraft was able to boast a new maximum takeoff weight of 833,000 pounds.

While an increased capacity variant had been considered during the 747 program’s earliest days, these higher-thrust engines paved the way for serious reconsideration now without the former need to sacrifice cargo loads or range for it.

Toward that end, studies completed in 1976 focused on a 23-foot fuselage stretch, attained by means of seven-frame forward and eight-frame aft insertions, along with a 27-foot upper deck increase, for a new mixed class passenger capacity of 570, as opposed to the previous 440. Yet depressed passenger demand during the late-1970s precluded the viability of this admittedly ambitious project and airline customer consensus pointed to a more modest stretch.

This took form as the 747SUD, or “stretched upper deck,” in the spring of 1980. Lengthened by some 23 feet, it incorporated 18 additional windows and two full-size, upward-opening doors with 45-foot-long evacuation slides. Although it carried an 8,000-pound, or two-percent, structural weight increase, the otherwise simplified modification increased its six-abreast accommodation from 32 to 69, reached by a new, straight, internal staircase that replaced the type’s signature spiral one.

Designated 747-300, it was offered as both a new-build version or a conversion of existing 747-200Bs, both of which factored into launch customer Swissair’s June 1980 order for four of the former and one of the latter. Powered by four 64,750 thrust-pound JT9D-7R4G2 engines, it first flew two years later, on October 5, and was type certified a year after that on March 4 at an 833,000-pound gross weight.

While the minimal change version offered a modest capacity increase, it introduced neither increased range nor any type of design enhancement.

747-400 Design and Development:

Several factors caused serious reconsideration of a more ambitious derivative of the 747 in the mid-1980s.

Sales, first and foremost, had been declining. The monthly production rate of seven airframes in 1979 had been reduced to a trickle of only one. Without revitalization, the program was likely to be terminated.

Currency and advancement, secondly, had not been maintained, a strategy that had kept the 727 and 737 programs alive with advanced versions, and the later, particularly, had spawned the Next Generation 737-300, -400, and -500 series.

Competition, thirdly, although not always on an even-keel basis, had begun to appear with step-change technology, as occurred with the DC-10-30 and -40, whose succeeding MD-11 introduced quieter, more fuel efficient engines and two-person digital cockpits. Airbus itself was about to unveil its own twin- and quad-engine A330 and A340 designs. The 747 appeared particularly outdated with its three-man, analogue cockpit, especially when measured against Boeing’s own new-technology narrow and widebody 757 and 767 offerings.

Finally, growth had shifted from the Atlantic to the Pacific, with unprecedented numbers of passengers and amounts of cargo being transported to China, Japan, and Korea.

What was needed was a modernized version of the venerable 747 with significant range to eliminate the intermediate stops in Alaska and Hawaii, yet not sacrifice payload. The remedy was initially envisioned as a version of the 747-300 with either Pratt and Whitney PW4000 or General Electric CF6-80C turbofans, an increased wingspan, and its resultantly greater wing integral fuel tank capacity.

Yet, most of the major, early 747 operators sought far more than these basic power and dimensional increases packaged in the proposed 747-300A, prompting Boeing to embark upon an extensive reassessment project so that the new version would be commensurate with late-20th century technology.

Devising, in fact, a five-point list to generate next-generation sales, it sought to incorporate state-of-the-art technology, considerably enhance the passenger cabin, increase the range by 1,000 miles, reduce fuel consumption by up to 37-percent over that of the original 747-100, and reduce operating costs by ten percent.

Designated 747-400 and announced in May of 1985, it was a significantly improved aircraft.

Although it retained the 231.10-foot overall length of all the previous standard versions and featured the stretched upper deck of the -300, it introduced a considerably modified wing. Built up of the 2000 copper and 7000 zinc series of aluminum alloys developed for the 757 and 767, which formed the torsion box’s upper and lower skins, and incorporating graphite composites, it featured both a six-foot span increase and six-foot winglets that were outwardly canted by 29 degrees and had a 60-degree sweepback. Eliminating the need for a greater span increase, these area-rule designed devices harnessed the vortex created by the upper and lower pressure differential remix at the tip, increasing area and lift, reducing drag, and retaining gate compatibility dimensions a greater stretch would not have achieved.

“Winglets,” according to Boeing, “are a new stabilization feature to compensate for wing and body structural changes.” They facilitated the transport of 40 more passengers 2,500 miles further.

While the ailerons, spoilers, and dual-section, triple slotted trailing edge flaps remained the same as those incorporated on previous 747 versions, an additional variable camber leading edge flap was installed, resulting in three inboard Krueger devices from the root to the inboard engines, five mid-wing ones between the powerplants, and the new total of six between the outboard one and the tip.

The construction materials increased the wing’s strength by between five and 13 percent, yet reduced aircraft weight by up to 5,500 pounds. Compared to the 195.8-foot span of the previous versions, the 747-400 had a 211.5 unfueled one or 213.0 one with full tanks, which caused a downward bend of the airfoil. Aspect ratio was 7.7 and area was 5,825 square feet.

Another 747-400 improvement was its powerplant. Because engine manufacturers had made significant progress in the design and development of advanced turbofans, particularly for long-range, widebody twins which were predicated upon increased reliability and thrust and decreased fuel consumption and noise, the latest 747 version was 40-percent quieter than its -300 series predecessor. As had occurred with the 747-200B, it was offered with poweprlants made by all three engine manufacturers.

The 56,750 thrust-pound Pratt and Whitney PW4056, for example, specified by launch customer Northwest Orient, featured single crystal turbine blades, full authority digital engine control (FADEC), a ten-percent high pressure compressor ratio increase, and a 27-percent greater high pressure rotor speed. It consumed seven percent less fuel than the earlier JT9D upon which it was based.

The 58,000 thrust-pound General Electric CF6-80C2B1F, first specified by KLM Royal Dutch Airlines, offered a four-stage low pressure compressor matched to the fan, a core airflow that increased from 276 to 340 pounds per second, and an overall pressure ratio of 30.4 to 1 produced by the 14-stage high pressure compressor. Like the PW4056, it was FADEC-equipped.

The Rolls Royce RB.211-524, featuring three-shaft, wide-chord blades, was offered in two versions: the 58,000 thrust-pound -524G and the 60,000 thrust-pound 524H. It was first ordered by Cathay Pacific.

All engines, regardless of type, were attached to redesigned, streamlined pylons.

The Pratt and Whitney Canada PW901A auxiliary power unit (APU), replacing the long-standard Allied Signal one for the first time, consumed 40 percent less fuel. It could maintain a 75-degree Fahrenheit cabin temperature while the aircraft was on the ground with a 100-degree external one.

Fuel, whose capacity varied between 53,985 and 57,285 US gallons for Pratt and Whitney and Rolls Royce engine-powered aircraft, and between 53,711 and 57,011 US gallons for General Electric powered ones, was stored in the fuselage center section and two main tanks per wing, along with reserve and vent surge tanks. Although minor modifications had been made to their plumbing and sensors, the 747-400’s major design feature was a 3,300-US gallon auxiliary tank in the 72-foot, 2.5-inch spanned horizontal tailplane, providing a 350 nautical mile increase. It was not, however, used for in-flight center-of-gravity variation.

Increased rudder authority, amending maximum deflection from a former 25- to a present 30-degrees, facilitated a ten-knot ground speed reduction in which it could maintain the effectiveness.

While the 747-400 retained the same five-truck, 18-wheel configuration of the earlier versions, it replaced the former steel brakes with carbon ones, which offered a 1,800-pound weight reduction, were rated for twice the number of landings, and cooled faster, increasing aircraft turn-around times. Larger tires necessitated a wheel diameter increase from 20 to 22 inches. Ai digital antiskid system was introduced.

Ice and rain protection encompassed total air temperature probes; window wipers, washers, and rain repellent; window heat; pitot-static probes on both sides; angle-of-attack sensors, again on both sides; wing anti-ice; and engine inlet cowl anti-ice.

Aircraft servicing points were many. Those on the fuselage included vacuum cleaning, oxygen, electrical, potable water, hydraulic, oil, air start, and air conditioning. Those on the wing encompassed the fuel vent, the gravity fuel port, the fuel itself, and the fuel control panel on the left wing underside.

Significant enhancements were made to the interior.

The cockpit, first and foremost, was transformed from a three- to a two-person one, with the fight engineer’s functions having been incorporated in an overhead panel and these were now automatically monitored.

Employing digital systems designed for the 757 and 767, it featured six eight-by-eight inch cathode ray tube (CRT) displays, consisting of the primary fight display (PFD) and the navigation display (ND) placed side-by-side in front of the captain and duplicated for the first officer, and two center engine indication and crew alerting system (EICAS) screens.

The pedestal between the two pilots contained the control display units (CDU’s), the fuel control switches, the parking brake lever, the radio communication panels, the audio control panels, the aileron and rudder control panel, the stabilizer trim indicator, the weather radar control panel, the transponder control panel, the autobrake selector panel, and the public address-interphone handset.

An extensive data base, subdivided into performance and navigation categories, replaced the performance manuals and navigation charts, and facilitated the rapid, extremely accurate calculations of any desired parameter in conjunction with the flight management computer (FMC).

Information was both enterable and retrievable by means of the control display unit keypads.

During cockpit setup, the lower of the two engine indicator and crew alerting system screens displayed the secondary engine data-that is, the N2 and N3 shaft speeds, vibration, fuel flow, and oil temperature, pressure, and quantity-while the upper continuously displayed the primary engine data, such as engine pressure ratio, the N1 fan speed, and the exhaust gas temperature (EGT). Yet enough screen space remained for additional aircraft status indications, including flap and undercarriage positions.

Compared to the 971 lights, gauges, and switches of the first generation 747’s analog cockpit, the current -400’s digital one featured only a third, or 365. The aircraft was certified for Category IIIB landings.

Boeing listed its fight deck avionics baseline capabilities as follows.

“8 x 8 integrated displays: air data, primary flight and navigation instruments; engine, subsystems, caution and warning alerts; systems status and synoptic (heads-down monitoring).

“Multipurpose control display unit (MCDU): primary interfaces – FMCS, standby nav (IRS), standby nav radio tuning; secondary interface – accesses CMCS, ACARS, AIDS, weight and balance.

“Advanced FMC software package: thrust management – autothrottle/thrust limit; altitude/speed flight profile intervention via AFDS MCP; Nav radio tuning – automatic and remote; worldwide nav data base capability; software improvements.

“Central maintenance computer system (CMCS): standardized subsystem bite with English language readout; interactive control of system LRU bite via MCDU; interfaces flight deck//avionic and associated airplane systems.

“Improved dispatch reliability: redundant control of mode functions for EFIS/EICAS/AFDS MCP; display function switching and triple EIFS/EICAS interface units.

“Digital audio control and radio communication systems.”

Aside from two observer seats, a windowless crew rest compartment, featuring one or two full-length bunks, reading lights, and fresh air vents, enabled extra pilots to attain legal rest periods on fights that could span up to 18 hours. A comparable, although much larger, cabin crew rest area, installed in the formerly unutilized rear roof from the last row of passenger seats to the rear pressure bulkhead and replacing the 747-300’s “Portakabin” one that had taken the place of up to 20 revenue-generating passenger ones, was accessible by a locked door, three-step, and vertical ladder entryway. Incorporating additional insulation and ceiling lighting to simulate day and night cycles, it was configured with varying numbers of bunks and sleeper seats.

The redesigned interior, which introduced an advanced widebody look, featured recontoured ceilings and sidewalls; concealed lighting; self-supporting ceiling panels; larger overhead side and center storage compartments; outboard, seat track lockable modular galleys; modular, vacuum flushable toilets, whose waste was stored in four rear tanks; and a digital in-flight entertainment system with seat-back monitors; and five main deck air conditioning zones with higher ventilation.

Inter-deck access, as had been provided on the 747-300, was via a straight stairway.

Class division, density, capacity, color, fabric, and decoration varied according to customer specification. A 416 tri-class configuration, for instance, entailed 23 first class seats at a 61-inch pitch, 80 business class ones at a 39-inch pitch, and 313 coach class ones at a 32-inch pitch. A dual-class cabin accommodating 497 entailed 42 first class and 455 coach seats. Five hundred twenty-four could be subdivided into 42 business class seats at a 42-inch pitch and 406 coach ones at a 32-inch pitch, with another 76 on the stretched upper deck, provisioned with its own galleys and lavatories.

Maximum main deck abreast seating in the four cabins behind the nose was ten, with two aisles, and six on the upper deck with a single aisle. Maximum, exit-limited passenger capacity was 624.

The 747-400’s lower deck hold volume of 6,035 cubic feet was subdivided into 5,190 cubic feet of unit loading device (ULD) space and 845 of bulk or loose-load space, facilitating the loading of 16 forward and 14 aft LD-3 containers or five forward and four aft 96-by-125-inch pallets.

As powered by the CF6-80C2 engine, it had a 390,700-pound operating weight, 144,300-pound payload capability, 535,000-pound zero-fuel weight, 384,824-pound fuel weight, a maximum takeoff weight that varied from 800,000 to 870,000 pounds, and a maximum landing weight that varied from 574,000 to 630,000 pounds. Range, at a long-range cruise speed with 412 passengers and reserves, was 7,300 nautical miles.

Construction of the first 747-400, registered N401PW, began in mid-1986 in Everett, by which time 49 aircraft had been ordered by Singapore, KLM, Lufthansa, Cathay Pacific, and British Airways. Northwest’s launch order, for ten, called for aircraft configured for 420 passengers. Major assembly occurred a little over a year later, in September, and the first roll-out, on January 26, 1988, entailed a dual-ceremony, dual-location event, since it marked the occasion of the first 737-400 rollout in Renton. Another 58 aircraft, by United and Air France, had been intermittently ordered.

The expected system glitches, along with the unexpected part and powerplant delivery delays, postponed the first flight of the PW4056-powered aircraft from March to April 29, 1988, followed by first General Electric and Rolls Royce examples in, respectively, June and August. The GE airframe set a new world gross weight record, leaving the runway at 892,450 pounds.

Certification, following a four-aircraft flight test program, was achieved on January 9, 1989. Delivered to Northwest 17 days later and entering domestic service between Phoenix and Minneapolis on February 9 for crew familiarization purposes, the first 747-400, powered by PW4056 turbofans, was placed in the Pacific-spanning skies it was intended for, from New York to Tokyo, on June 1.

Other first deliveries included those to KLM and Lufthansa, on, respectively, May 18 and May 23 with General Electric engines, and to Cathay Pacific on June 8 with Rolls Royce powerplants. On the August 17 delivery flight to Qantas, the type set a world distance record from London to Sydney, covering the 9,688 miles in 20 hours, eight minutes.

By May 25, 1990, the 747-400 had attracted 279 firm orders.

747-400 Versions:

As had occurred with the basic 747, and particularly with its -200B series, Boeing offered several variants of the 747-400.

The first of these was the 747-400 Combi Featuring mixtures of main deck passenger and cargo loads, the latter in two aft zones, it incorporated a 120- by 130-inch aft, port, upward-opening door, strengthened floor, and freight loading system, facilitating several load combinations, including 268 passengers and seven pallets, 290 passengers and dix pallets, or up to 13 pallets. The type was first delivered to KLM on September 1, 1989.

Another variant was the 747-400D for “domestic.” Considered an advanced counterpart to the earlier 747SR for short, high-density Japanese sectors, it omitted the six-foot wing extensions and winglets, was powered by lower thrust engines, and offered a 600,000-pound maximum takeoff weight, although it was certifiable up to 870,000 pounds.

The first 747-400D, which was the 844th 747 airframe of all versions, first flew in March of 1991 and was delivered to Japan Air Lines in October. All-Nippon Airlines, another operator, configured the aircraft for 27 business and 542 economy class passengers.

The 747-400F, yet another version, replaced the 747-200F, whose production was discontinued after Air France placed a launch order for five on September 13, 1989. Devoid of passenger windows and facilities, and employing the standard-length upper deck of the 747-100, -200, and -SP, it featured both upward-opening nose and side cargo doors, a flight deck-reaching foldable ladder, and a two-person crew rest area. It could carry 26 more tons of cargo 1,200 miles further than its earlier -200F counterpart.

Volume totaled 27,467 cubic feet, including 21,347 on the main deck, 5,600 in the lower deck holds, and 520 in the bulk. Two ten-foot high pallets could also be accommodated on the upper deck.

The first 747-400F, the 968th 747 built, was first rolled out on February 25, 1993, and first took to the skies three months later, on May 4. The type’s maximum gross weight was 875,000 pounds. Because Air France had since canceled its order, Cargolux inaugurated the type into service instead.

The last version was the 747-400ER, intended, as its designation indicates, for “extended range” operations. Initially offered to Qantas as the 747-400IGW “increased gross weight,” it featured one or two 3,064-US gallon auxiliary tanks installed in the hold, increasing fuel capacity to 63,403 gallons and range to 7,500 nautical miles with one tank and 7,700 miles with two.

Powered by 63,300 thrust-pound PW4062 engines, the -400ER had a 535,000-pound zero-fuel weight, a 910,000-pound maximum takeoff weight, and a 652,000-pound landing weight. Design range with 416 passengers was 7,585 miles.

On September 10, 1993, the 1,000th 747, a -400 series for Singapore Airlines, was rolled out, making it the fifth Boeing type to achieve this production milestone after the 707, 727, 737, and (originally McDonnell-Douglas) MD-80. By January 1, 2002, 41 operators had ordered 630 747-400s of all versions. Production ultimately totaled 694.

The Boeing 747: The End of an Era

The Boeing 747, often referred to as the “Jumbo Jet,” was a remarkable commercial jetliner for its time. The world’s first ever wide-body airplane produced, the so called “Queen of the Skies,” boasted an upper deck, and a passenger capacity that remained unrivalled for decades.

The 747-100 first entered service in 1970 with, the now defunct, PanAm. The -200 model followed in 1971, featuring more powerful engines and a higher MTOW (Max Take-Off Weight). Boeing followed this up with the shortened 747SP (Special Performance), which featured a longer range, and entered service in 1976.

Boeing then launched the -300 model in 1980, which resulted from studies to increase the capacity of the 747. The -300 featured fuselage plugs and a stretched upper deck. This variant, along with the -100, -200, and SP, were collectively referred to as the 747 “Classics.” It was now time for a more significant upgrade.

The most common version, the 747-400, entered service in 1989. This variant featured, along with the stretched upper deck of the -300, more fuel-efficient engines, and was the first to feature a 2-crew glass cockpit, eliminating the requirement for a flight engineer, and is also the most common variant in service. The -400 has a longer wingspan than the classics and was fitted with winglets, which reduced drag, and is the most common aesthetic feature used to distinguish the variant from the -300.

The 747-400 dominated the long-haul market for years to come. It was operated by almost every major airline in the world, dominating every major international airport. It wasn’t until the late 2000’s that the -400 had to face competition, after the larger Airbus A380 entered service. Boeing eventually responded by launching a new larger, more fuel-efficient variant.

The third generation 747-8 was launched in 2009, with Lufthansa, and entered service in 2012. This variant boasted a composite fuselage, as featured on the 787, and more fuel-efficient engines. It also featured an increase in capacity, thanks to the stretched fuselage and upper deck. Sadly, it failed to capture the market and was unable to match, let alone surpass, the success of the -400.

The four-engine 747’s time is coming to an end, with an increasing number of airlines retiring the type in favour of more efficient twin engine aircraft. The latest passenger variant, -8, failed to attract as many sales as Boeing had hoped, having earned less than 50 orders from mainly 3 airlines, as the quad can no longer compete with the likes of the 777, 787, and Airbus A350.

Despite this the 747 enjoys a great reputation as one of the most successful airliners in history. As we see an increasing number of smaller, twin engine aircraft in its place, the industry will always remember the beauty and grace with which the Boeing 747 adorned our skies.