Profile – Boeing 747 Part III

In order to prove the Orbiter’s flying characteristics, it was necessary to launch it at altitude from a shuttle carrier aircraft (SCA). At first, a specially designed machine was considered, but the expense and time delay were unacceptable. Instead, the National Aeronautics and Space Administration (NASA) purchased Boeing 747 #N9668 from American Airlines in mid-1974 for $US16 million and dispatched the airliner to Boeing for modifications.

Mods included the installation of additional bulkheads, skin reinforcement and the provision of a fin at the tailplane tips to give directional stability when carrying the Orbiter. To carry the Orbiter, three pylons, two aft and one forward, were mounted on top of the fuselage, matching the attachment points provided for the external fuel tank used during ground launches. Normally retracted to a low position during ferry flights, the forward pylon extended to raise the craft’s nose for inflight separation.

By 1977 both aircraft were ready for trials. These called for 13 flights carried out in three phases at Edwards Air Force Base in California. The first batch involved five unmanned trips with the Orbiter firmly attached to the 747 mother ship. These were successfully completed between February 18 and March 2.

The second phase came in June/July when three flights were carried out with the astronaut crews on board. This gave them the opportunity to try out the flight systems without actual separation. No serious problems developed and again everything was judged satisfactory.

On August 12, piloted by Fred Haise and Gordon Fullerton, Enterprise was finally released for its first free flight. The crew fired explosive bolts to release the Orbiter from the 747, which then made an unpowered landing at Edwards AFB. The protective tail cone remained in place on this and the following two flights in order to reduce drag and turbulence. For its maiden trip, Enterprise was released at 24,000ft (7300m). Flying time logged was just 5 min 21 sec.

The tail cone was removed on October 12 for the spacecraft’s fourth free flight. Two simulated main and orbital maneuvering engines were installed to test stability, particularly during approach and landing. Separation was made at 25,200ft (7700m). This time, without the cone in position, Enterprise experienced considerably increased drag and the angle of descent was much steeper than previously experienced. Touchdown speed was 185kt (343kmh).

The last free flight occurred on October 22, 1977, with Haise and Fullerton again at the controls. Released at 19,000ft (6700m), it flew a straight-in approach to Edwards AFB and landed after only 2 min 1 sec. It proved that the Shuttle could be safely landed on the available 15,000ft (4570m) runways at both Kennedy Space Center and Vandenberg AFB, the sites chosen for landings after space missions.

Following these successful tests for fitting Shuttles to the transporters at Kennedy and Vandenberg, NASA announced plans on February 29, 1988, to acquire another Boeing 747-100 to serve as a second SCA. For this, a 747SR was selected because of its similarity to the original SCA and to minimize costs associated with modifications and operation. Purchased from JAL as #8117, the Boeing Defense & Space Group’s Wichita Branch carried out modifications under a $US55 million contract which increased the basic weight of the aircraft by 5232kg (11,525lb).

In detail, these modifications fell into two areas: Type I (permanent structural and system modifications) and Type II (removable structures and systems).

Type I Modifications Included:

• Installation of bulkheads to strengthen the fuselage;
• Addition of skin reinforcements at critical stress areas;
• Reinforcement and modification of the 747’s horizontal stabilizer to allow attachment of special tip fins;
• Installation of fittings to attach struts for holding the orbiter to the fuselage; and
• Removal of interior equipment (passenger seats, galleys, etc).

Type Ii Modifications Included:

• Orbiter forward and aft support structure and fairings for use during ferrying missions;
• Stabilizer tip fins measuring 25.4 x 50.8cm (10 x 20ft) for added directional stability when carrying the orbiter.

The second SCA was similar to the first except that it had extra support built in to give it the capability of transporting a shuttle orbiter with a maximum gross weight of 108,960kg (240,000lb), about 21,790kg (48,000lb) more than the original. It was designed for 265 ferry missions over a 15-year period and delivered on November 20, 1990.

Bigger – The Series 300 Stretch Programme

Stretched versions of the Boeing 747 were on the drawing boards at Seattle soon after the first Jumbo had been launched in 1966. At the time, first priority was, of course, to get the initial version of the aircraft into service. Then, with 180 on order by the time Pan Am flew the first revenue passengers to London in January 1970, there was no pressing need to push ahead with an aircraft offering even greater capacity. The 747-100 itself could already carry double the passengers of any other airliner in commercial service.

In the 1970s the airline business went into one of its seasonal declines and orders for the 747, like for most other types, fell to an all-time low of just seven aircraft in 1971 and averaged less than two a month for the next five years. By 1977, however, signs of a revival (orders averaged five a month 1977-1980) encouraged Boeing to revive its interest in stretching the 747. One idea was to launch a 747 with fuselage “plugs” ahead of and behind the wings with a matching extension of the upper deck to increase seating to about 600. Another was the possibility of providing an upper deck over the entire fuselage length, increasing capacity to around 700 passengers.

Both of these proposals proved over-ambitious for an airline industry that, by 1980, was beginning to feel the first effects of another recession. From the numerous project studies made at Seattle there eventually emerged a more modest “stretch”, offered as the 747SUD (stretched upper deck). This acronym was soon changed to 747EUD (extended upper deck). As the designation (which was eventually to change again to 747-300) suggested, the principal innovation of this new model was an extension of the upper deck along the fuselage by extending the rear fairing back 7.11m (280in). This doubled the upstairs seating capacity to a possible maximum of 85, giving the basic 747-300 a total capacity of 496 passengers, increasing to a possible high-density arrangement for 624 in a short-range -300SR version, compared with 550 in the -100SR.

With the access stairway to the upper deck located centrally at the rear of the new extension, there was greater flexibility to use the deck for any class, or combination of classes. The increased payload was gained at very little cost, certainly less than if the whole fuselage was lengthened. Airlines needed to make no changes to lower deck arrangements, including Combi layouts, that had already been proved to meet their individual needs, but gained additional revenue from the extra seats upstairs. Using the same engine choices and maximum weights already cleared for the -200B, the 747-300 could be phased into an airline’s operations with the minimum of fuss.

Since the empty weight was increased, there was a reduction in maximum range with a given payload, but offsetting this to some extent was the fact that the new contours gave an aerodynamic advantage. The deeper fuselage above the wing actually reduced drag and thus helped to reduce fuel burn. For given weights and cruising speeds, combined with the latest engine improvements and the extra passenger capacity, the result was an improvement of 9 to 11% in fuel usage per passenger.

Swissair became the launch customer for the stretched upper deck 747, ordering five with an option on four more in 1980; two of the five were to be Combis. The order represented a total investment by Swissair of $US550m and made the 747-300 probably the first “nine-figure” transport in airline history, at more than $US100,000,000 each. Boeing rolled out the first of Swissair’s 747-300s at Everett on September 21, 1982, and its first flight followed on October 5. Swissair had specified Pratt & Whitney JT9D-7R4G2 engines, but another early customer, UTA, chose General Electric CF6-80C2s, and the second -300, fitted with these engines, flew on December 10, 1982. FAA certification of the new version was obtained on March 7, 1983, and deliveries began immediately. Swissair put the type into operation on March 28, followed by UTA three days later.

The 747-300 enjoyed a trouble-free introduction to service, and to make the advantages of the Series 300 more widely available, Boeing developed a conversion package, allowing operators of the -200 to have their aircraft upgraded. This called for a 28.96m (95ft) length of the upper fuselage to be removed, from immediately behind the flight deck, to allow the new sections to be spliced in — a process requiring some eight weeks at Everett. However, KLM was the first and only operator to sign up for conversion.

Better — The Series 400

Only two years or so after the introduction of the 747-300, Boeing announced its intention to offer an advanced long-range version known as the Series 400. After getting the extended upper deck 747-300, airlines pressed Boeing to give them a Jumbo capable of flying nonstop over most of their intercontinental routes against the prevailing winds. Within twelve months of the first 747-400 order placed by Northwest in October 1985, seven more customers — Singapore, KLM, Lufthansa, Cathay Pacific, UTA, British Airways and Korean – had signed contracts for nearly 100 aircraft. The first 747-400 was delivered three years later in January 1989, the 13th model to be produced.

Although its fuselage length remained the same as the first 747 which entered commercial service on January 21, 1970, as did its tail height and body width, the new version incorporated significant improvements in aerodynamics, structural materials, avionics and interior design that give it more range, better fuel economy and lower operating costs than its predecessors. It could carry more people faster and further. The new aircraft’s range capability of 7300 nautical miles (13,520km) gave an increase of 1000nm (1852km) over the -300 model. By comparison, the design range of the original 747-100 was 4000 nautical miles (7408km). In addition to giving more range, the 747-400 consumed 9 to 12% per seat less fuel than the -300 and realized a fuel saving of up to 25% per seat kilometer over older 747s still in service.

Until Qantas decided in August 1989 to set a new commercial air transport record on the airline’s first 747-400 delivery flight, the record was held by a 747SP with a distance of 8910nm (16,501km) from Seattle to Cape Town. The Rolls-Royce powered Qantas aircraft, carrying 186.5 tonnes of fuel and a token load of 23 people, flew 9720nm (18,011km) from London to Sydney in 20 hours and 9 minutes, finishing with 5.7 tonnes of fuel remaining.

The prototype 747-400 thunders down the runway about to take to the skies on another test flight. This shot shows in particular to great effect the wing with flaps and slats extended. (Boeing)

The most obvious aerodynamic improvements, designed to reduce fuel burn and extend the 747-400’s range, were the increased wing span and 1.83m (six foot) high winglets, swept back at 60 degrees and angled outwards at 29 degrees. These composite and aluminum winglets help reduce the vortex drag caused by the whirling pattern of air round the wingtips swirling up around the ends from positive to negative pressure and creating drag by pushing down on top of the wing. By dissipating the vortices, the winglets give a 3% gain in efficiency over earlier model 747s and a resulting improvement in fuel consumption. The wing span increased from 59.64m (195ft 8in) to 64.44m (211ft 5in), which stretched out to 64.9m (213ft) under the weight of a full fuel load of 216,926 liters (47,718 imp gal).

The wing-to-body fairing was recontoured for drag improvement. Additional efficiency came from newly designed nacelles and struts for the advanced engines — Rolls-Royce RB211-524G, Pratt & Whitney PW4000s or General Electric CF6-80C2s – each producing about 58,000lb (260kN) thrust compared to the 46,960lb (210kN) powerplants of earlier models.

A hidden improvement was the more extensive use of higher strength aluminum alloys in the wing. These gave a 2270kg (5000lb) weight saving despite the larger wing area, which has been increased by 13.9m² (150sq ft) to 524.9m² (5650sq ft). One wing weighs 12,700kg (28,000lb), ten times that of Boeing’s first 1916 aircraft the B&W (Boeing and Westervelt) Model 1 seaplane.

The use of advanced materials allowed considerable structural weight reductions throughout. Carbon brakes on the 18 landing gear wheels brought an estimated weight saving of 817kg (1800lb). Metal flooring in the passenger cabin was replaced by light, tough, graphite composite floor panels. Overall the empty weight of the -400 was around 11 tonnes lighter than the -300.

A completely new flight deck design transformed the control of the 747-400 from a three-crew aircraft to one with a two-pilot operation, while at the same time significantly cutting the individual workload of each pilot, both before and during flight. Rest areas were provided for relief pilots and cabin staff carried on the longer nonstop flights. The number of flight deck lights, gauges and switches was reduced from 971 to 365 (22 fewer than the twin-engined 757 and 767 and 100 less than the 737). Workload was designed to be half to a third that of the standard 747, which many pilots now have designated the ‘Classic’.

Second-generation digital avionics replaced analog avionics, so the flight deck had a completely new look. The usual array of dials and lights on the instrument panel were replaced by six 20cm (eight inch) square color cathode ray tube (CRT) displays, with five lined up horizontally from left to right and the sixth immediately below the middle one. These displayed all the flight control, navigation, engine and crew alerting functions. The Flight Engineer’s panel was removed, with some functions displayed in the CRTs and others, such as controls for air conditioning, hydraulic, electrical and fuel systems, moved to the overhead panel in easy reach of the pilots — not that they needed to touch the fuel controls because under normal circumstances these were programmed automatically.

The two outboard CRTs, mounted in front of the pilots, functioned as the captain’s and first officer’s primary flight displays (PFD). Each could use the PFD as the single source for all the primary flight instruments found on a traditional instrument panel, with tape formats displaying altitude, airspeed and heading conditions. Speed, height and track ‘bugs’ could be computed and preselected, minimizing mental calculations. The center of the PFD display provided an artificial horizon.

The two inboard CRTs gave each pilot a navigation display, portraying the aircraft’s position relative to the earth, with functions for flight planning, route definition and approach guidance. If a CRT should fail, automatic or manual display switching could be used as a backup.

The two center CRTs constituted the Engine Indication and Crew Alerting System (EICAS). These displays provided the crew with all the engine and system information needed to manage the aircraft safely. The top one showed the primary engine parameters, crew alerting messages, and information such as the position of the gear and flaps when required; while the lower could show eight different functional diagrams of the aircraft’s technical systems. Virtually all systems were self-monitoring and reported their condition to EICAS. Crew alerting messages would be displayed only if there was a fault that caused system degradation. Five levels of color coding distinguished between urgent, cautionary and advisory warnings. Before flight, the aircraft could tell the crew its mechanical condition by listing defects in notes on the center CRT. Updates could be obtained at any time in flight.

Three Smaller Monochrome Crts Were Grouped On The Aisle Stand Around The Throttles. Called Control Display Units (Cdus), These Crts, Together With The Mode Control Panel Above The Windscreen, Provided Access To The Flight Management Computers (Fmc) Which Programmed The Flight Plan And Operated The Autopilots. From Takeoff To Blind Landing Down To Category Iii Minima, The 747-400 Could Happily Accept Instructions To Fly Itself – Leaving The Two Pilots To Simply Monitor Its Progress. If One Fmc Failed, The Crew Still Had All Normal Fmc Operations Available. If Both Fmcs Failed, The Cdus Could Display A Map With Point-To-Point Route Information. No Single Fault Could Prevent The Autopilot System From Compleing An Autoland.

Further Variants

In addition to the long-range, all-passenger model, Boeing has produced three complementary models in the 747-400 family. All share the benefits of superior range and payload capability, low fuel consumption, and two-crew efficiency.

The 747-400M Combi allows airlines to adjust their cargo and passenger capacity to meet seasonal fluctuations. In a three-class passenger arrangement with six or seven main deck cargo pallets, it can carry 268 passengers and up to 41 tonnes of cargo. The Combi can also be reconfigured for long-range, 400-passenger operations. It provides 955nm (1770km) greater range with 5450kg (12,000lb) more payload than previous Combis. KLM was the first to purchase the 747-400M, with further orders following from five other airlines.

The 747-400D domestic carries up to 566 passengers in a two-class arrangement on high-density domestic and regional routes. The wing does not feature winglets, though it has the structural strengthening needed for high-cycle, short-haul services; fuel efficiency per seat is about 15% better than on earlier versions. It can also be converted for long-range 747-400 operations by adding the wingtip extensions and winglets.

The swing-nose 747-400F freighter can transport more cargo farther nonstop than any other commercial jet freighter. Compared to the 747-200 Freighter, it has 20.3 tonnes more payload capacity, or 1000nm (1850km) longer range, with 12% better fuel burn per kilo of payload. The -400F has winglets but retains the shorter upper deck of the 747-200. The first -400F freighter was delivered to Cargolux at the end of 1993.

For the future, it is possible that the fuselage will be stretched with plugs fore and aft of the wing, taking the overall length to almost 78m (256ft). Meanwhile, the 747-400 family is still keeping the costs of air travel down and airline profits up and it remains the standard by which passengers around the world judge airliner comfort.

A measure of the success of this magnificent aircraft can be taken by the original Boeing estimation in 1966 that the new jumbo jet might in its lifetime sell as many as 400 units. Now, some 28 years later firm sales total 1200 whilst it is probably not too ambitious to predict that a decade from now the 747 will still be in production. Boeing may have got the sales projection part of the operation very, very wrong but certainly made up for it with the quality of the actual product – indeed this pioneering airliner has more than won her title as ‘The Queen of the Skies’.

747 Chronology

Spring 1963 – Engineering group is organized to plan an aircraft which meets passenger and cargo growth predicted for the 1970s and beyond.

March 1966 – Boeing board of directors decides to proceed with 747 programme.

April 1966 — Pan American World Airways announces it will purchase 25 Boeing 747s.

June 1966 — 780 acres acquired adjacent to Paine Field, Everett, Washington, for 747 manufacturing plant.

September 1966 — Airline orders for new superjet reach value of $US1.8 billion.

January 1967 — Production operations for 747 begin at the Everett plant.

May 1967 – Everett assembly building — world’s largest — is activated.

Late 1967 – First nose section arrives at Everett plant from Wichita Division; components manufactured by major subcontractors begin arriving.

Mid-June 1968 – Pratt & Whitney JT9D test engine flown by Pratt & Whitney on B-52 testbed.

September 30, 1968 — First 747 completed and rolled from factory.

November 1968 – Boeing announces a longer-range 747 capable of greater payloads, to be designated 747B. Freighter and convertible versions also to be offered.

February 9, 1969 — Initial flight of first 747 completed. Flight test programme begins.

December 30, 1969 — US Federal Aviation Administration certificates 747 for commercial passenger service.

January 21, 1970 – Pan American begins Boeing 747 commercial service on New York/London route.

July 16, 1970 – Millionth passenger carried on 747s.

November 12, 1970 – 747B sets world heavy weight record, taking off at 372,269kg (820,700lb) gross weight.

December 23, 1970 – 747B certificated.

February 12, 1971 – Boeing 747 equipped with fail-operative triple autopilot system certificated for operation in category IIIA conditions.

February 26, 1971 – 100th 747 delivered.

December 1971 — Delivery of 747s with new sound-suppressing nacelles begins.

March 8 1972 – First T4tf Freighter, For Lufthansa Certificated. September 1972 – 747 Fleet Logs 1,000,000 Flight Hours. October 30 1972 — Boeing Announces It Will Produce Short Range Version Of The 747. Japan Air Lines Announces Order Forfour Of The New Version, Designated 747sr.

April 17, 1973 – 747C convertible passenger cargo airliner certificated by FAA and delivered to World Airways.

August 1973 – Boeing announces it is proceeding with development of a “Special Performance” 747.

September 10, 1973 – Pan American World Airways becomes the first airline to order the 747SP.

October 7, 1973 – The first 747SR (Short Range) enters service with Japan Air Lines between Tokyo and Naha, Okinawa.

February 15, 1974 – Sabena Belgian World Airways is first carrier to get 747 with side cargo door modification.

July 5 1974 – Klm-Royal Dutch Airlines Orders First362,880kg (800,0001b) Gross Weight 747b Powered By General Electric Cf6-50e Engines.

December 1974 – Tropical cyclone Tracy — a Qantas 747 sets a world record by carrying 674 evacuees from Darwin.

April 8, 1975 – 747 approved for 32 passengers on upper deck when fitted with left side upper deck emergency exit.

May 19, 1975 – First 747SP (Special Performance) airliner rolls out.

June 27, 1975 – British Airways orders 747s powered by Rolls-Royce RB211-524 engines.

July 4, 1975 – First 747SP makes initial flight completing the test series. Top speed attained was Mach .92.

October 1975 — 747 fleet carries 100 millionth passenger.

December 10, 1975 – Boeing 747SP lands at Boeing Field, Seattle, completing a two-day worldwide demonstration tour.

February 4 1976 — The 747sp Is Certificated By The Federal Aviation Administration For Commercial Use.

March 5, 1976 – First 747SP delivered to Pan American World Airways.

March 24, 1976 – A South African Airways 747SP sets a world distance record for commercial aircraft.

May 3, 1976 – A new around-the-world record set by a Pan American 747SP. Elapsed time 46 hours 26 minutes.

November 1, 1976 — A new world record for maximum mass lifted to 2000 metres claimed for 747B powered by Rolls-Royce RB211 engines.

February/March 1977 — First Batch Of Test Flights With The Nasa Orbiter Attached To 747 Mother Ship.

September 30, 1977 – The worldwide fleet of more than 300 747s passed the million flight hours mark.

October 28-30, 1977 – Pan Am 747SP set a new speed record for an around-the-world flight passing over both Poles.

December 21 1978 – First 747-100b Delivered, To All Nipponairways.

December 21 1979 — 100th Main Deck Cargo 747 Delivered, A 747c To Transamerica Airlines.

June 11, 1980 – Boeing announces a new version, the 747-300 with extended upper deck.

December 19 1980 – 500th Rollout, A 747-200b For Sas.

December 15, 1981 – Largest 747-300 order; eight for Singapore Airlines.

September 21, 1982 — First 747-300 rollout (Swissair livery).

March 1983 — T47-300s Enter Commercial Service (Swissairand Uta).

October 1985 – Boeing announces 747-400 launch sale to Northwest.

January 1988 – 747-400 rolls out.

September 30, 1988 — First 747 celebrates 20th anniversary of rollout.

January 1989 — First 747-400 delivered to Northwest.

May 1989 – Certification Of Pw4056 On 747-400.

May 1989 – Certification Of Cf6-80c2bif On 747-400.

June 1989 – Certification Of R8211-524g On 747-400.

August 16, 1989 – Qantas sets the world distance record for commercial airliners flying London to Sydney nonstop.

September 1989 – 747-400F Freighter order announced for Air France. First 747-400 Combi delivered to KLM.

March 28 1990 – First 747 (N7470) Is Donated To Seattlemuseum Of Flight.

May 1990 – Boeing No Longer Offers Airline Customers747-200/300 Series.

November 20 1990 – Second Nasa Space Shuttle Carrierdelivered.

May 24-25 1991 – Elal Israel Airlines 747-200c Sets A Newrecord By Airlifting 1086 Refugees From Addis Ababa To Israel,with The Birth Ofa Baby En Route, It Lands With 1087 Passengers.

December 1993 — The first 747-400F freighter delivered to Cargolux.