OK, so where were we? Fast forward to Dec 4 and its all systems go again at Everett where Boeing flight test personnel are swarming like bees around ZA001 and ZA002, with plans apparently underway to get both flying before year-end.
ZA002 (nearest camera) will enter ground testing on Dec 7. (photo Liz Matzelle)
Let’s run down what we know has been happening since ZA001 was rolled back out to the flight line on the evening of Nov 30. The Rolls-Royce Trent 1000 engines on ZA001 were fired up back into life on the evening of Dec 1, around the same time that rumors of the first flight date began shifting from the previously reported Dec 22 to Dec 14. Since then, of course, they have shot backwards and forwards with all the predictable volatility of the stock market. See Jon Ostrower’s report for a summary of those changes, together with a pretty reliable conclusion that Boeing is shooting for a first flight sometime between Dec 14 and 22. What’s the betting Boeing will try for Dec 17th – the 106th anniversary of the Wright Brothers first flight?
But let’s talk about what is happening now and over the next few days. Thrust reverser ground tests were successfully run on Dec 3, with additional engine runs. Rolls-Royce has developed, tested and flown (three weeks ago on its 747 flying testbed) new FADEC software, which was also loaded and tested at the same time. New engine health monitoring software, and the standard for service entry, was also tested and is now broadcasting via the aircraft’s ACARS link. This is enabling Rolls engineers in the UK to review engine diagnostic data at almost the same time as engineers in Seattle.
Thursday also saw the start of checks of the engine indicating and crew alerting system, and the on-board processor that works out the aircraft’s gross weight and center of gravity – two vital metrics for flight testing. The batteries for the electrically actuated brake system were also checked out. This morning (Friday 4th), the aircraft’s hydraulic system was also pressurized and carefully checked for leaks, while later the same day the flight control system and latest software was evaluated.
This weekend there will be no let up with tests due tomorrow of the engine electronic controls and more flight control software regression tests, along with associated engine runs. The weekend will also see additional system software updates tested over two long blocks, the second of which will extend into the small hours of Sunday morning. The crew who will monitor the flight from the ground in the telemetry ground station will also run through rehearsals over the weekend.
Meanwhile engineers plan to ‘wake up’ ZA002 with a series of ground tests starting on Dec 7. According to Flightblogger, the aircraft is currently having its fuel tanks washed out prior to re-activation, adding to the evidence that ZA002 is indeed due to quickly follow ZA001 into the air.