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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 CF6-80C2B5F, the
2
BOEING 747-400 Jumbo Jet
Pratt & Whitney PW4062 and the Rolls-Royce RB211-524H. These engines provide up to 63,000 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flooring, previously used in the passenger cabin, has been replaced by light, tough graphite composite floor panels.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.
The 747-400 flight deck provides flexibility that is being incorporated in more models across the Boeing fleet. The
747-300’s 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 can now obtain an update of the airplane's mechanical condition while in flight, whereas
before, the information was only available to maintenance workers when the airplane was parked.
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.
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
　
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