Boeing has completed flight and performance tests of the first 777-200IGW (increased gross weight) powered by the "Block 4" variant of the General Electric GE90-90B turbofan.

The aircraft is being refurbished at the company's Everett site in Washington before delivery to Lauda Air in late September.

The newest GE90 variant has a simplified, lighter, combustor configuration which "-produces better operability and enhances durability", says Dick Ostrom, manager, GE90 programme integration. "The new combustor is basically a DAC 1 [dual annular combustor] that has been simplified ," he adds.

Flight tests have confirmed a greater exhaust-gas-temperature margin and improved combustor efficiencies, although the engine maker declines to provide exact numbers. Other changes to the Block 4 configuration, which also include improvements from the recent Block 3.5 move, involve tweaks to the fuel system, including revisions of the fuel-delivery manifold and the fuel nozzles. The switches help reduce overall engine weight by around 37kg.

The GE90 has logged over 100,000 flight hours with no in-flight shut-downs and a 99.97% dispatch reliability rate in revenue service, says GE. It is in service on 20 British Airways and China Southern Airlines Boeing 777s. This number is expected to grow to 29 by the end of the year, with a 777 delivery to Lauda, the first six to Saudi Arabian Airlines and two to International Lease Finance.

Source: Flight International