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• First operation was beginning of 1997.
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• Last check-up was September 16 2000
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• SIA safety measures is beyond the World's Aviation safety regulations.

The improved and advanced 747-400 delivers more range, better fuel economy and lower operating costs than the previous 747 models. The 747-400 has a range of approximately 8,300 statute miles (13,360 km) and the lowest cost per seat-mile of any twin-aisle airplane offered by any manufacturer. It has a dispatch-reliability rate of 98.8 percent.

Boeing delivered the first 747-400 in 1989 to Northwest Airlines. Since the first 747 delivery in 1969, Boeing has delivered more than 1,230 747s, of which 500 are high-technology 747-400s. The 747's longevity and popularity are based on its unbeatable low seat-mile costs, flexibility, long-range dominance, unmatched comfort options and ability to integrate new technology.

Aerodynamics and Structural Materials
The 747-400's most noticeable aerodynamic improvement is the 6-foot longer wing with a 6-foot-high winglet angled upward and slightly outward. This change reduces fuel burn and extends the airplane's range. While designing the 747-400, Boeing engineers discovered that the kind of wing shape needed by the airplane created a whirling pattern, called a vortex, at the wingtip while the airplane moved through the air at cruising speed. The top part of that whirling movement of air actually pushed down on the top of the wing, creating drag.

Initially, it was thought that the problem could be solved by adding several feet to the wing, but that would make it difficult to navigate increasingly crowded airport taxiways and ramps. Longer wings also would reduce the number of airport terminal gates available to the 747-400. The acceptable solution came in the form of a compromise that involved lengthening the wing by 6 feet and adding the winglet.

The winglet provides the effect of having an even greater wingspan without outgrowing the standard airport slot. The wingtip extension and winglet offer a fuel mileage improvement of about 3 percent, which during the lifespan of an airplane amounts to considerable savings for the airlines and their passengers. The durable and lightweight winglets are made of graphite-epoxy materials, currently used on the Boeing 737, 757, 767 and 777 airplanes. The composite and aluminum winglet saves 60 pounds (27 kg) per airplane compared to an all-aluminum structure.

Boeing also recontoured the wing-to-body fairing for drag improvement and achieved additional efficiency from newly designed nacelles and struts for the airplane's advanced engines: the General Electric CF6-80C2, the Pratt & Whitney PW4000 and the Rolls-Royce RB211. These engines provide up to 62,000 pounds of thrust.

Use of advanced materials allows considerable structural weight reductions throughout the 747-400. Metal flooring, previously used in the passenger cabin, has been replaced by light, tough graphite composite floor panels.

Structural carbon brakes are standard on the 747-400's 16 main landing-gear wheels. They provide improved energy absorption characteristics and wear resistance, as well as an estimated 1,800-pound (816 kg) weight savings over previous brakes.

The 747-400 also achieved weight savings of approximately 4,200 pounds (1,900 kg) by using higher-strength aluminum alloys with improved fatigue life. These alloys, introduced on the 757 and 767, are incorporated in the 747-400's wing skins, stringers and lower-spar chords.

Flight Deck
The 747-400 flight deck provides flexibility that is being incorporated in more models across the Boeing fleet. The 747-300 three-crew analog cockpit was transformed into a fully digital, two-crew flight deck with cathode ray tube (CRT) displays. Six 8- by 8-inch (200 by 200 mm) CRTs are used to display airplane flight control, navigation, engine and crew-alerting functions. They allow more information to be displayed with fewer instruments. The number of flight deck lights, gauges and switches was reduced to 365 from the 971 on the 747-300. Flight crew workload is designed to be one-half to one-third that of former 747 models.

In the event of an individual CRT failure, automatic or manual display switching is used as a backup. The Engine Indicating and Crew Alerting System (EICAS) can call up the status or schematics of various systems at any time on one of the CRTs. Crews now can obtain an update of the airplane's mechanical condition while in flight, whereas before the information only was available to maintenance workers when the airplane was parked.

Interior Design
Boeing redesigned the interior of the 747-400 to improve passenger comfort, convenience and appeal. Ceiling and sidewall panels were recontoured with new, lighter-weight materials that provide an open, airy look. Passenger stowage capacity increased to 15.9 cubic feet (0.4 m³) in each 60-inch (152 cm) outboard stowage bin, or 2.9 cubic feet (0.08 m³) per passenger.

New laminate materials were designed to meet Boeing fireworthiness goals. A new thermoplastic blend reduces smoke and toxicity levels in the event of fire, and upper-deck ceiling panels are made of improved polyester and phenolic sheet molding materials instead of polyester.

Interior flexibility allows airline operators to relocate class dividers and galley and lavatory modules more quickly to serve market requirements. Lavatory installation is simplified by a vacuum waste system, and additional locations for galleys and lavatories are available. These "quick-change features" allow major rearrangement within 48 hours, while seats and compartments can be changed overnight.

Boeing also revised the 747-400 air-distribution system. This increases the main deck cabin air distribution zones from three to five, which allows ventilation rates in each zone to be regulated based on passenger density.

For the first time on any airliner, an optional cabin crew rest area uses space in the rear of the fuselage above the aft lavatories. This area, which can be configured for eight bunks and two seats, provides privacy as well as comfort for off-duty flight attendants. By relocating the crew rest to this area, 10 more profit-making seats are available on the main deck of the aircraft.

Increased Range and Flexibility
An optional 3,300-U.S.-gallon (12,490 L) fuel tank in the horizontal tail boosts the 747-400's range an additional 400 statute miles (650 km). The 747-400 also has a new 1,450-horsepower auxiliary power unit (APU) that provides an estimated 35 percent to 40 percent reduction in fuel consumption, better air pressurization performance on hot days, higher electrical output and reduced noise levels. Mounted in the rear fuselage, the APU supplies pressurized air for air conditioning and engine starting while the airplane is on the ground, plus electrical power to operate lights and other requirements during stops. The new APU also can be retrofitted to earlier 747s.

The 747-400 is available in passenger, combi, freighter and domestic configurations. The 747-400 Combi is two airplanes in one, carrying both passengers (forward) and cargo (aft) on the main deck. The 747-400 Freighter is the largest commercial cargo transport in service, and the 747-400 Domestic is a high-capacity (568 passengers) airplane that incorporates structural improvements to accommodate the increased takeoff and landing cycles of short-range operations. Because it does not need the drag-reducing capabilities of the 747-400's longer wing and winglet, the 747-400 Domestic uses the same wings as the 747-100, -200 and -300 models.