General Electric CF6

The General Electric CF6, US military designations F103 and F138, is a family of high-bypass turbofan engines produced by GE Aviation. Based on the TF39, the first high-thrust, high-bypass jet engine, the CF6 has been used in a wide variety of airliners. It has been superceded by the GEnx in newer airliners.^[2]

CF6
At NASA's Glenn Research Center in 1979
Type	Turbofan
National origin	United States
Manufacturer	GE Aviation
First run	1971
Major applications	Airbus A300 Airbus A330 Boeing 747 Boeing 767 Lockheed C-5M Super Galaxy McDonnell Douglas DC-10 McDonnell Douglas MD-11 Kawasaki C-2
Number built	8,300 (2018)[1]
Developed from	General Electric TF39
Developed into	General Electric LM2500 General Electric LM6000

The CF6 core has been used for the LM2500, LM5000, and LM6000 industrial & marine gas turbines.

Overview

A CF6 turbofan installed at the Spanish National Institute for Aerospace Technology

After developing the TF39 for the C-5 Galaxy in the late 1960s, GE offered a higher thrust variant for civilian use, the CF6.^[3] GE proposed the CF6 to Eastern Airlines, for the Lockheed L-1011 and the McDonnell Douglas DC-10. Lockheed used the Rolls-Royce RB211 as its exclusive engine, but the CF6 was chosen for the DC-10, and entered service in 1971. It was also selected for versions of the Boeing 747, and then for the Airbus A300, A310 and A330, Boeing 767, Lockheed C-5M Galaxy, and McDonnell Douglas MD-11.

By 2018, GE had delivered more than 8,300 CF6s: 480 -6s, 2,200 -50s, 4,400 -80C2s, more than 730 -80E; and 3,000 LM6000 industrial and marine derivatives. The in-service fleet included 3,400 engines, generating over 600 shop visits per year.

Variants

CF6-6

CF6-6 diagram

CF6-6 cutaway

The CF6-6 was first used on the McDonnell Douglas DC-10-10.

It has a single-stage fan with one core booster stage driven by a 5-stage LP (low pressure) turbine, and a 16-stage HP (high pressure) axial compressor driven by a 2-stage HP turbine; the combustor is annular; separate exhaust nozzles are used for the fan and core airflows. The 86.4-in (2.19-m) diameter fan generates an airflow of 1,300 lb/s (590 kg/s), resulting in a bypass ratio of 5.72. The overall pressure ratio is 24.3. The engine develops a maximum static take-off thrust of 41,500 lb (185.05 kN).

Undeveloped variants

The CF6-32 was to be a lower-thrust derivative of the CF6-6 for the Boeing 757. In 1981, GE stopped work on this engine so no longer competed with Pratt & Whitney and Rolls-Royce on this aircraft.^[4]

CF6-50

The CF6-50 series are rated between 51,000 and 54,000 lb (227.41 to 240.79 kN, or '25 tons') of thrust. It was launched in 1969 to power the long range McDonnell Douglas DC-10-30, and was derived from the earlier CF6-6.

Not long after the -6 entered service, an increase in thrust was required. It was obtained by increasing the airflow through the core. Two booster stages were added to the LP (low pressure) compressor and the last two stages of the HP compressor were removed^[5] which increased the overall pressure ratio to 29.3. Although the 86.4 in (2.19 m) diameter fan was retained, the airflow was raised to 1,450 lb/s (660 kg/s), giving a static thrust of 51,000 lb (227 kN). The increase in core flow decreased the bypass ratio to 4.26.

In late 1969, the CF6-50 was selected to power the then new Airbus A300. Air France became the launch customer for the A300 by ordering six aircraft in 1971. In 1975, KLM became the first airline to order the Boeing 747 powered by the CF6-50. This led to more variants, such as the CF6-80. The CF6-50 also powered the Boeing YC-14 USAF AMST transport prototype.

The CF6-50 was also offered with 10% less thrust, and known as CF6-45, for the 747SR, a short-range version used by All Nippon Airways for domestic Japanese operations.

The engine, known by its military designation F103, is used on the KC-10 Extenders and Boeing E-4.

Starting in 1977, a derivative known as the LM5000 was offered as an industrial gas turbine. The first unit was sold in 1978, with 30 orders by 1 October 1988.^[6]

CF6-80

CF6-80C2K1F Engine for the Kawasaki C-2

Display engine showing internal parts at The National Air and Space Museum in Washington, D.C.

Display engine showing internal parts: compressor at right, combustor and HP turbine in center, and LP turbine at left

The CF6-80 series has a thrust range of 48,000 to 75,000 lb (214 to 334 kN).

There are 4 variants.

CF6-80A3

The CF6-80A3, with thrusts from 48,000 to 50,000 lb (214 to 222 kN), powered two twinjets, the Boeing 767 and Airbus A310. The GE-powered 767 entered airline service in 1982, and the GE powered A310 in early 1983. It is approved for ETOPS operations.

For the CF6-80A/A1, the fan diameter remains at 86.4 in (2.19 m), with an airflow of 1435 lb/s (651 kg/s). Overall pressure ratio is 28.0, with a bypass ratio of 4.66. Static thrust is 48,000 lb (214 kN). The basic mechanical configuration is the same as the -50 series.

CF6-80C2

For the CF6-80C2-A1, the fan diameter is increased to 93 in (2.36 m), with an airflow of 1750 lb/s (790 kg/s). Overall pressure ratio is 30.4, with a bypass ratio of 5.15. Static thrust is 59,000 lb (263 kN). An extra stage is added to the LP compressor, and a 5th to the LP turbine.^[7]

The CF6-80C2 is used on fifteen commercial and military widebody aircraft including the Boeing 747-400, and McDonnell Douglas MD-11. The CF6-80C2 is also approved for ETOPS-180 for the Airbus A300, Airbus A310, Boeing 767, KC-767A/J, E-767J, Kawasaki C-2, and (as the F138) the Lockheed C-5M Super Galaxy and VC-25A.

F138-GE-100

The F138-GE-100 is a military designation given to the modified version of the CF6-80C2, to produce 50,400–51,600 lb, with Strict Noise Regulations and Green Emissions, for the Lockheed Martin C-5M Super Galaxy. The F138 replaced the TF-39 when the Galaxy was upgraded to the Super Galaxy.

CF6-80E1

The CF6-80E1 has the highest thrust of the CF6-80 Series, with the fan tip diameters increased to 96.2 in (2.443m), and an overall pressure ratio of 32.6 and bypass ratio of 5.3.^[8] The 68,000 to 72,000 lbf (300 to 320 kN) variant competes with the Rolls-Royce Trent 700 and the Pratt & Whitney PW4000 to power the Airbus A330.^[9]

Other variants

The industrial and marine development of the CF6-80C2, the LM6000 Series, has found wide use including fast ferry and high speed cargo ship applications, as well as in power generation. The LM6000 gas turbine family provides power in the 40 to 56 MW range for utility, industrial, and oil & gas applications.^[10]

Parts of unknown origin

In 2023, Bloomberg reported that European aviation regulators had determined that London-based AOG Technics, majority owned by Jose Zamora Yrala, whose nationality is listed as British on some forms and Venezuelan on others, supplied parts of unknown origin and false documents for repairs on CF6s.^[11]

Applications

• Airbus A300/Airbus Beluga
• Airbus A310/Airbus A310 MRTT/Airbus CC-150 Polaris
• Airbus A330/Airbus A330 MRTT/EADS/Northrop Grumman KC-45
• Boeing 747/E-4/VC-25A
• Boeing 767/E-767/KC-767/E-10
• Boeing YC-14
• Kawasaki C-2
• Lockheed Martin C-5M Super Galaxy
• McDonnell Douglas DC-10/KC-10
• McDonnell Douglas MD-11

Accidents and incidents

In 1973, a CF6-6 fan assembly disintegrated, resulting in the loss of cabin pressurization of National Airlines Flight 27 over New Mexico, United States.^[12]

In 1979 a CF6-6 engine detached from the left wing of American Airlines Flight 191 due to faulty pylon maintenance, severing hydraulic lines and causing the aircraft to crash.

In 1989, a CF6-6 fan disk separated from the engine and damaged all three hydraulic systems. The flight, United Airlines Flight 232, continued with no hydraulic power until it crash-landed at the airport in Sioux City, Iowa.

In 2000, the National Transportation Safety Board (NTSB) warned that the high-pressure compressor could crack.^[13]

Following a series of high-pressure turbine failures on 6 September 1997,^[14] 7 June 2000^[15] and 8 December 2002,^[16] and resulting in 767s being written off on 22 September 2000,^[17] on 2 June 2006,^[18] and on 28 October 2016,^[19] the Federal Aviation Administration issued an airworthiness directive mandating inspections for over 600 engines and the NTSB believed that this number should be increased to include all -80 series engines with more than 3000 cycles since new or since last inspection.^[20]

In May 2010, The NTSB warned that the low-pressure turbine rotor disks could fail.^[21] Four uncontained failures of CF6-45/50 engines in the preceding two years prompted it to issue an "urgent" recommendation to increase inspections of the engines on U.S. aircraft : none of the four incidents of rotor disk unbalance and subsequent failure resulted in an accident, but parts of the engine did come through the engine casing each time.^[22]

Specifications

CF6 Specifications^[23]

Variant	CF6-6	CF6-50	CF6-80A	CF6-80C2	CF6-80E1
Type	Dual rotor, axial flow, high bypass ratio turbofan, annular combustor
Compressor	Fan & 1LP + 16HP	Fan & 3LP + 14HP		Fan & 4LP + 14HP
Turbine	2HP + 5LP	2HP + 4LP		2HP + 5LP
Length	188 in (478 cm)	183 in (465 cm)	167 in (424 cm)	168 in (427 cm)
Overall diameter	105 in (267 cm)[24][25][26]			106–111 in (269–282 cm)[7]	114 in (290 cm)[7]
Fan diameter	86.4 in (219 cm)[27]			93 in (236 cm)[28]	96.2 in (244 cm)[29]
Takeoff thrust	41,500 lbf 185 kN	51,500–54,000 lbf 229–240 kN	48,000–50,000 lbf 210–220 kN	52,200–61,960 lbf 232.2–275.6 kN	65,800–69,800 lbf 293–310 kN
Pressure ratio	25–25.2	29.2–31.1	27.3–28.4	27.1–31.8	32.4–34.8
Bypass ratio	5.76–5.92[24]	4.24–4.4[25]	4.59–4.66[26]	5–5.31[7]	5–5.1[30]
TSFC	0.35 lb/lbf/h 9.9 g/kN/s[24]	0.368–0.385 lb/lbf/h 10.4–10.9 g/kN/s[25]	0.355–0.357 lb/lbf/h 10.1–10.1 g/kN/s[26]	0.307–0.344 lb/lbf/h 8.7–9.7 g/kN/s[7]	0.332–0.345 lb/lbf/h 9.4–9.8 g/kN/s[7]
Application[31]	DC-10-10	747, DC-10-15/30, KC-10A, A300	A310, 767	A300, A310, 747-400, 767, E-767, Boeing KC-767, C-2, C-5M, MD-11	A330, A330 MRTT
Type Certificate Data Sheet	CF6-6[32]	CF6-50[32]	CF6-80A[33]	CF6-80C2[33]	CF6-80E1[34]
Weight[a]	8,176 lb 3,709 kg	8,825–9,047 lb 4,003–4,104 kg	8,760–8,776 lb 3,973–3,981 kg	9,480–9,860 lb 4,300–4,470 kg	11,225 lb 5,092 kg
Maximum fan rpm	3,810	4,102	4,016	3,854	3,835
Maximum compressor rpm	9,925	10,761	10,859	11,055	11,105
Thrust-to-weight ratio	5.08	5.84–5.97	5.48–5.7	5.51–6.28	5.86–6.22

1. Dry, includes basic engine accessories & optional equipment

See also

Related development

• General Electric TF39

Comparable engines

• Ivchenko-Progress D-18
• Pratt & Whitney JT9D
• Pratt & Whitney PW2000
• Pratt & Whitney PW4000
• Rolls-Royce RB211
• Rolls-Royce Trent 700

Related lists

• List of aircraft engines