Boeing has reactivated the fourth 787 development aircraft in readiness for initial flight tests of the first engine for the stretched 787-9.

The aircraft, ZA004, which has been in long-term storage at Boeing Field, Wa., since last year, completed a series of check flights June 8-9, before departing for flight tests in Kona, Hawaii on the June 10.

The aircraft is currently powered by the latest Rolls-Royce ‘Package B’ standard Trent 1000 engines but in July will be fitted with the first set of upgraded ‘Package C’ standard engines which will later power the 787-9.

ZA004 was one of the original four Rolls-powered development 787s and joined the test program in February 2010.

Package C will be rated at 74,000-lb. thrust, and is designed to have 1% better fuel burn relative to the current engine, which itself clawed back a 2.2% improvement over the first versions of the Trent 1000.

The engine is due to be certified mid-year, and will be the baseline engine for the 787-9 when it enters service with Air New Zealand in mid-2014.

The Package C version is also due to begin powering 787-8s from around June 2014.

As well as improved fuel burn, the Package C engine incorporates modifications to increase mass flow and exhaust gas temperature margin. Main changes include modified blades in the intermediate pressure compressor and a semi-active case cooling system for improved tip clearance control in the low-pressure turbine.

A Package C engine successfully completed a 150-hr. endurance type test and FAA over-temperature test in Derby, U.K., late last year just as various elements of the upgrade began flight tests on the Rolls-Royce 747 flying testbed in Tucson, Ariz.

Flights on the testbed have been conducted in three main phases, culminating with a recent full-up Package C configuration. Early flights involved tests of a hybrid Package B engine incorporating the tip clearance controls of the newer powerplant in one instance, and the revised compressor in the other.