Boeing 747-8 systems differences from the 747-400

Treat the 747-8 as a heavily modernised, stretched 747-400 rather than a clean-sheet design: same type certificate, same conventional bleed-air and hydraulic philosophy, but new engines, more electrical capability and subtle systems upgrades everywhere.

Key facts
Type certificate	Shares A20WE with the 747-400 (derivative, not a new type)
Engines	GEnx-2B only — ~13% better fuel burn than the -400’s CF6
APU	PW901C with two 120 kVA generators (vs -400’s two 90 kVA)
Not bleedless	Conventional pneumatic/hydraulic architecture — not a 787-style more-electric aircraft

Compared with the 747-400, the -8 looks different first: a fuselage about 5.6 m longer, raked wingtips instead of winglets, and GEnx-2B engines whose shared core and 80 percent of line-replaceable units come from the 787’s GEnx-1B.

Systems changes include increased electrical generation, an upgraded PW901C auxiliary power unit, a larger main-deck flight-attendant rest (up to ten berths adjacent to door 5 in some cabins) and an optional second flight-deck position that gives -8 crews the same pilot type rating as the -400.

Deliveries total 155 (48 Intercontinental, 107 Freighter) against 694 of the -400 family, ending 54 years of 747 production in January 2023.

Sources

• Boeing 747-8 special conditions (MTOW to 970,000 lb) — US Federal Register
• Overhead flight attendant rest on the 747-8 — US Federal Register
• GEnx-2B powers the 747-8’s first flight — GE Aerospace
• 747-8 Airplane Characteristics for Airport Planning — Boeing
• Boeing 747 article — Wikipedia