CFM International (CFMI) is working to get its CFM56-7 series turbofan certificated on schedule before the beginning of November.

The latest version of the successful CFM56 family, the -7 is being developed to power the new-generation Boeing 737. The 737-700 is due to have its maiden flight in January 1997, and enter service with Southwest Airlines the following October.

CFMI, a joint venture between General Electric of the USA and France's Snecma, has been forced to re-design the engine's fan-blade-retention device for a third time, after blade-off tests again revealed that the component was not stiff enough.

The -7 is the first of the CFM56 family to use wide-chord fan blades, and these are around 35% heavier than those of the -3, which powers current-generation 737s.

Meanwhile, CFMI is developing the CFM56-9, a derated version of the -7, to power new-generation 100-seat regional jets proposed by Aviation Industries of China (Air Express AE-100) and Indonesia's IPTN (N2130). The -9 will have a thrust rating of 82-102kN, using the -7 core but with a smaller, 1.42m-diameter wide-chord fan.

The company says that its development time scale calls for the engine to be certificated around three years after the launch of the AE-100 regional jet.

Snecma had hoped that CFMI would proceed with development of the so-called CFMXX turbofan to power future growth versions of the Airbus A340.

This project, however, was effectively killed when General Electric signed an exclusive study agreement with Airbus for an A340-500/600 powerplant.

The CFM56-5C powers current versions of the A340

Source: Flight International