Boeing's 787 test aircraft ZA004 returned to flying on 21 May with the first Rolls-Royce Trent 1000 Package B engine hung under its right wing.
It marked the beginning of tests on the updated powerplant, which is meant to deliver specific fuel consumption (SFC) rates within 1% of the engine-maker's initially targeted specification.
The fourth 787 test aircraft had been down for maintenance since 27 April for installation of the engine and its extensive instrumentation. However, the aircraft performed a flight of around 4h, travelling along the US Pacific coast. The upgraded left-hand engine is expected to be installed on ZA004 later this month, programme sources said.
The Package B engine includes a revised six-stage low-pressure turbine design, high-aspect-ratio blades, relocation of the intermediate-pressure compressor bleed offtake ports and a fan outlet guide vanes with improved aerodynamics.
It is also believed that the Package B engine also incorporates undisclosed hardware changes that were prompted following the August 2010 uncontained failure of a Package A-model Trent 1000 on the Rolls-Royce test stand in Derby, UK.
The test fleet, which Boeing said in April had completed 95% of certification requirements, had been flying with the Package A engine since the 787's first flight in December 2009.
Boeing and Rolls-Royce have not disclosed whether or not first 787 deliveries in the third quarter to All Nippon Airways will include the Package A or B engines, although initial planning prior to the most recent programme delays indicated the first five or six Trent-powered 787s to be delivered would feature the A-model engine.
Rolls-Royce received extended twin-engine operations (ETOPS) certification on the Package A engine on 9 May, clearing the way for engine-airframe ETOPS certification to be undertaken.
Boeing also offers a choice of General Electric GEnx-1B engines on the 787.