This year’s Singapore Airshow heralds the final stages of the Rolls-Royce Trent 1000 TEN-powered Boeing 787-10’s service-entry effort, as the Civil Aviation Authority of Singapore prepares validation of the U.S. FAA's amended type certificate for operation with launch customer Singapore Airlines in the second quarter of the year. Issued on January 22, the FAA award capped a certification program involving three flight-test airplanes—two powered by Rolls-Royce Trent 1000 TENs and one by GEnx-1Bs—that together flew a total of more than 900 hours. Boeing expects certification of the GE-powered 787-10 in time for scheduled first delivery to United Airlines in the second half of the year.
Speaking with AIN just ahead of the show, Boeing 787 chief project engineer Bob Whittington explained that Boeing had originally planned to use four test airplanes in the program, but as the 787-10’s commonality with its smaller sibling, the 787-9, became more and more apparent during the early stages of design, so did the lack of a need for much of the testing to demonstrate the differences between the two models.
The 787-10 and -9 use 95 percent common part numbers, not only reducing the number of test hours needed for the -10 but undoubtedly aiding workflow once full-scale production of the latest Dreamliner begins in North Charleston, South Carolina. Apart from its 18-foot stretch, the only visually obvious difference between the -9 and -10 lies in the -10s semi-levered main landing gear, leaving only some minor structural reinforcements in the fuselage and some systems modifications to account for the bigger cabin. Boeing (Stand U23, U09) arrived at the 18-foot stretch by inserting five frames in front of the wing and four frames aft of the wing, allowing for the addition of 40 passenger seats and total capacity of 330 in a two-class layout. Using exactly the same wing as the -9, the -10's only other significant differences involve localized strengthening of the fuselage, an increase in the capability of the environmental control system (ECS) and enough extra cargo space for one more pallet or two extra LD-3 containers in both the forward and aft holds.
While maximum landing weight increases by 20,000 pounds to 445,000 pounds and maximum zero fuel weight jumps 25,000 pounds to 425,000 pounds, maximum takeoff weight remains unchanged at 560,000 pounds. Range decreases to 6,430 nm from 7,635 nm.
Completing function and reliability trials and ECS testing ahead of schedule, the third airplane, designated ZC002, finished testing first and revealed no surprises since its first flight during the summer. “It actually performed better than expected,” said Whittington.
By the time Whittington spoke with AIN on January 5, the first airplane—Trent 1000 TEN-powered ZC001—had completed all but a final stage of stability and control software validation, performing crosswind landings and tailwind takeoffs in Newfoundland. Incorporating technologies from the Trent XWB and Advance engine including a “rising-line” compressor and three-stage bladed disc (blisk) at the front of the high-pressure compressor, the Trent 1000 TEN promised a 3-percent fuel burn advantage over the Trent 1000, the original Rolls option for the 787-8 and 787-9. Entering service with an Air New Zealand 787-9 and a Scoot 787-8 last November, the Trent 1000 TEN has not delivered quite the fuel burn performance Rolls promised. Whittington said Boeing is awaiting a new software package to recoup the less than one-percent deficiency by mid-year.
However, in the 787-10, Boeing’s aerodynamic measurements showed a roughly one-percent better-than-expected drag coefficient improvement, thereby countering the slight deficiency experienced in the Trent 1000 TEN-powered -8 and -9.
Overall, Whittington expressed complete satisfaction with the pace and performance of the aircraft program. As much as the smooth introduction of the 787-9 contrasted with the tortured path of the 787-8’s launch to its entry into service, the 787-10 has done as well as if not better than the -9. “It’s a tough comparison to make because of that commonality difference,” explained Whittington. “The -8, of course, was so unique and so new and so innovative, that flight-test program was very long and very complicated. The big difference for us is the customers told us they really wanted the -10 to be as common as we could with the -9, and that really did structure out test program. It’s more common than any airplane that I know of. I’ve been here 32 years, and this has been the most straightforward test program that I’ve ever seen.”
Built exclusively in Charleston largely because the mid-body fuselage section cannot fit in a Dreamlifter for transport to Boeing’s plant in Everett, Washington, the first -10 moved through the South Carolina factory “significantly easier” than the first -9 moved thorough Everett, added Whittington. “The 787-10 flowed seamlessly through the production system,” he said. “We had half the number of manufacturing problems on the -10 than we did on the -9 in terms of non-conformances written, and the total flow through the factory is almost identical. The manufacturing system doesn’t really know the difference between a -9 and a -10.”
In an effort to ensure that its customers, too, will see little difference between the two models while flying them in revenue service, Boeing spent a lot of time and energy validating maintenance manuals and preparing to operate the airplanes in flight test much like an airline would. Meanwhile, the group of airlines that composed the program’s advisory panel—including Singapore—emphasized their strong desire for commonality over range. “The group of customers that we worked with were key in telling us not to stretch the range on the -10, that building in weight or capability in the airplane that they didn’t necessarily need for range was not as valuable to them as it being common to the -9,” said Whittington.
As of mid-January holding orders for 171 of the 787-10s, Boeing most recently inked a letter of intent with Emirates Airline during November’s Dubai Airshow, calling for an eventual firm order for 40. On the decision to choose the Dreamliner over the Airbus A350, an order for 70 of which Emirates canceled some three years ago, Emirates chairman and CEO Sheikh Ahmed bin Saeed Al Maktoum explained that fleet planners looked closely at both options and reached the conclusion that the Boeing product made the most sense for several reasons, including maintenance cost considerations.