Power began flowing through the electrical systems at 5 a.m. last Friday. The process is a series of tasks that methodically energize and activate the aircraft's systems beginning mostly with the electrical, before moving on to pneumatics and hydraulics.
The move keeps Boeing on schedule for the 250-ft. 2-in. long aircraft to roll out from the factory by the end of September and begin flight testing in the fourth quarter.
Boeing planned to conduct a test of the rigging for the door of the ram air turbine (RAT) on Monday but has deferred that work until next week pending completion of more assembly work. The RAT, which is making its debut on the 747 series, drops down in an emergency to provide back-up electrical power.
First adopted on the Lockheed L-1011, a RAT is common on most modern designs, including the Airbus A380, which is equipped with a Hamilton Sundstrand unit capable of generating emergency AC power up to 90 kVA.
The increased electrical demands of the 747-8 made the RAT a requirement. The stretched version also will use a unit developed by Hamilton Sundstrand. The 747-8 RAT module will include a turbine governor assembly, which will power a pressure compensated hydraulic pump.
This photo of the 747-8F's move last week emphasizes just how large the new airplane is. With an 18-ft. fuselage extension, the hump that made the 747 profile so famous from its service introduction in January 1970 is far less prominent. Airbus's A340-600 was the longest jet aircraft at 247 feet, but when it enters service late next year, the 747-8 will take the title back.
Meanwhile, the second 787, ZA002, moved under its own power for the first time Monday as part of final systems check-out tests prior to the start of work to refurbish the side of body wing root structure.
Taxi tests are expected to continue for two days, but will not be as extensive as those conducted on ZA001 in late June and early July. The taxi tests mark the last time any outside activity will be seen on the 787 program for several months until ZA001 re-emerges from its modification program later this year.
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Originally Posted by DHG750R
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