General Electric CF6 / F103 / F138
After the successful development in the late 1960s of the TF39 for the C-5 Galaxy, GE offered a more powerful development for civilian use as the CF6, and quickly found interest in two designs being offered for a recent Eastern Airlines contract, the Lockheed L-1011 and McDonnell Douglas DC-10.
Although the L-1011 would eventually select the Rolls-Royce RB211, the DC-10 stuck with the CF6, and entered service in 1971. It was also selected for versions of the Boeing 747. Since then, the CF6 has powered versions of the Airbus A300, 310 and 330, Boeing 767, and McDonnell Douglas MD-11.
The NTSB issued warnings regarding the cracking of the high pressure compressor in 2000 and failure of the low pressure turbine rotor disks in 2010.
The basic engine core formed the basis for the LM2500, LM5000, and LM6000 marine and power generation turboshaft. GE intends to replace the CF6 family with the GEnx.
A complete disintegration of a CF6-6 fan assembly resulted in the loss of cabin pressurization of National Airlines Flight 27 over New Mexico, USA in 1973. The failure of a CF6-6 was the primary cause of the Sioux City, Iowa USA crash of United Airlines Flight 232 in 1989.
Because a significant increase in thrust and therefore core power was required not long after the -6 had entered service, General Electric could not increase (HP) turbine rotor inlet temperature significantly, so they took the very expensive decision to reconfigure the CF6 core to increase its basic size. They achieved this by removing two stages from the rear of the HP compressor (even leaving an empty air passage, where the blades and vanes had once been located). Two extra booster stages were added to the LP (low pressure) compressor, 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 1450 lb/s (660 kg/s), yielding a static thrust of 51,000 lbf (227 kN). The increase in core size and overall pressure ratio significantly raised the core flow, resulting in a decrease in 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 was the first airline to order the Boeing 747 powered by the CF6-50. This led further developments to the CF6 family such as the CF6-80. The CF6-50 also powered the Boeing YC-14 USAF AMST transport prototype.
Four uncontained failures of CF6-45/50 engines in the preceding two years prompted the U.S. National Transportation Safety Board to issue an "urgent" recommendation to increase inspections of the engines on U.S. aircraft in May 2010. None of the four incidents of rotor disk imbalance and subsequent failure resulted in an accident, but parts of the engine did penetrate the engine housing in each case.
Following a series of high-pressure turbine failures, some which resulted in 767s being written off, the FAA has issued an airworthiness directive mandating inspections for over 600 engines. 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.
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 lbf (214 kN). The basic mechanical configuration is the same as the -50 series.