The engine family that spanned four decades of the 747

General Electric's high-bypass CF6 gave airlines their first alternative to the JT9D and stayed on the 747 for four decades, from the -200 to the -400ER.

Key facts
Applications	747-200, -200B, -200M, -200F, 747SR, -300, -400, -400ER; also E-4A and VC-25A
Key versions	CF6-50 (51,000 - 54,000 lbf); CF6-45A2 46,500 lbf (747SR); CF6-80C2B1 56,700 lbf (-300); B1F 57,900 lbf (-400); B5F 62,100 lbf (-400ER)
Bypass / fan	CF6-50 4.26:1, 86.4 in fan; CF6-80C2 5.15 - 5.31:1, 93.0 in fan
First customer	KLM - first CF6-powered 747 (747-200M), ordered October 1975

The first GE-powered 747 was a 747-200, not a 747-100 - the -100 was JT9D-exclusive. The USAF's selection of the CF6-50 for the E-4A 747 in 1972 helped clear the way, and KLM's October 1975 order for a CF6-powered 747-200M Combi brought the engine to the commercial fleet. JAL and Korean Air followed.

GE tailored engines for specific 747 customers: the CF6-45A2, a 10-percent-derated CF6-50 built only for ANA's high-cycle 747SR domestic operations, and the heavier CF6-50E for the 747-200 and 747-200F.

The CF6-80C2 was the decisive version, powering the 747-300 and then most 747-400s (the B1F at 57,900 lbf) plus the 747-400ER (B5F at 62,100 lbf). It became the most-flown widebody engine in history, with more than 300 million hours, and remains the benchmark the 747-8's GEnx was measured against.

A general-purpose engine family

The CF6 became one of the most widely flown turbofans ever, and its reach across the 747 is a large part of why. GE did not build a single 747 engine; it built a family that scaled and derated to suit different customers and missions. The CF6-50 series powered the -200 and the -200F; the CF6-45A2 was a deliberate 10-percent derate built only for ANA's high-cycle 747SR domestic work, trading thrust for the durability a short-haul high-cycle aircraft needed; and the CF6-80C2 family powered the -300, most -400s and the -400ER.

That breadth is the story. A -200 in 1975 and a -400ER three decades later share a name and a lineage, and the fleet that GE built support for is enormous.

The variant that decided the -400

The CF6-80C2 was the version that mattered for the long-lived -400 fleet. The B1F rating of 57,900 lb powered standard 747-400s, and the higher-thrust B5F powered the 747-400ER. When the 747-8 arrived, the CF6-80C2 it replaced was the benchmark the GEnx-2B was measured against - and by the standards of the era, it was the most-flown widebody engine in history, with hundreds of millions of flight hours behind it.

Customer-specific tailoring

GE tailored ratings to individual 747 operators throughout the family's life, from the ANA 747SR derate to the heavy CF6-50E for the -200F. This practice of customer-specific power is threaded through the whole 747 story and is covered in more depth on the thrust ratings page.

Related

• Fuel system
• Hydraulic systems
• Electrical system
• 747-8 systems differences