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Boeing Forges Ahead with Flight-test Campaigns

 - November 8, 2017, 12:00 PM
In early October, Boeing rolled out the first 787-10 built for launch customer Singapore Airlines—dubbed ZC003—as it began series production. (Photo: Boeing)

For a manufacturer with a high public profile, Boeing Commercial Airplanes can on occasion be surprisingly coy. Questioned regarding progress with various jetliner variants (and sub-variants), it restricts comments to “Limited information is available publicly on our flight-test program.”

There is inevitable interest from industry and the wider traveling public in, for example: numbers of test flights and flight-hours (FH) scheduled and logged; completion of test campaigns; certification progress; and such milestone events as demonstrations of Vmu [minimum “unstick” speed] and cabin evacuation trials, and ultimate load tests). But information remains curtained. “We do not release these details related to current flight test programs,” Boeing told AIN.

Nevertheless, the U.S. manufacturer is busily at work preparing for the 777-9 large twin-aisle twinjet scheduled to fly in 2019, completing the 787-10 test campaign and finalizing certification work on the re-engined single-aisle 737 Max 9 (737-9). Here is a summary of what we know about each:

787-10

In late September, Boeing delivered the 600th example of its 787 “middle-of-the-market” twin-aisle jet, six years and one day after handing over the first. About a week later, at its North Charleston final-assembly facility in South Carolina, Boeing completed final assembly of and rolled out 787 Line Number (LN) 622—dubbed ZC003—the first -10 built for launch customer Singapore Airlines—as the company began series production of this third variant (following the 787-8 and -9).

This aircraft is not the very first of the new variant, since two other examples have entered flight-testing since the first flew in March, and it might not even inaugurate 787-10 commercial service with the Asian carrier in about five months. Unofficially, the airline’s second such machine (LN656/ZC004) is expected to be the first to arrive in Singapore, possibly in March.

Meanwhile, after painting, LN622/ZC003 was scheduled to begin system checks, fueling and engine runs, and by late October had reached the flight line, according to Boeing.

“We are making progress [with testing] and are 70 percent complete,” reported the manufacturer, while declining to provide further information about cumulative flight-hours logged, remaining tests, and a likely completion date. This longer variant, which involves an 18-foot (5.5-meter) “stretch” of the basic 787-9, is assembled exclusively at North Charleston because its long center-body section cannot fit in the 747-based Dreamlifter transporter.

The first aircraft to fly, Rolls-Royce Trent 1000 (T1000)-Ten-powered ZC001/LN528, is being used to test automatic landing (autoland), avionics, envelope expansion, flutter, propulsion, primary flight controls, and stability and control. It was followed into the air in May by second example ZC036/LN548, which is fitted with the alternative General Electric GEnx-1B engines.

ZC036 is used for aircraft maintenance manual (AMM) validation, flutter, performance and stability and control work. The other 787-10 test aircraft—T1000-TEN-engined ZC002/LN565—sports a passenger-cabin interior and is used for AMM validation, fuel-consumption measurement, performance, and systems (including enhanced environmental control) testing.

Asked about current flight test activities, Boeing said, “All three of our flight-test airplanes [ZC001, ZC036, and ZC002] are in test.” Singapore Airlines has ordered 49 aircraft—making it also the variant’s largest customer—and has taken options on an additional six.

777X

In May General Electric ran GE9X engine Number 002, the first full certification-standard example of the 777X’s exclusive powerplant. Boeing expects to have completed all detail-design work for the aircraft (comprising the -8 and -9 variants) before 2018. The manufacturer is preparing to begin performing the avionics, power and other systems ground testing.

Also by year-end, Boeing plans to have integrated aircraft systems for representative performance evaluation in a ground-test article. “Several ‘labs’ are running; others will continue to come online through the rest of [2017] and early next year,” Boeing told AIN.

By late October the manufacturer had delivered the front and rear spars for the first flying 777X to the wing assembly area at Everett, Washington. The first new-composites wing, the longest such unit Boeing has ever built, was earmarked for the static-test specimen—the first assembled 777-9 airframe that is to be joined later by the sixth example, which will be used for dynamic fatigue testing.

The 777X flight-test campaign will involve four 777-9s, to be built during 2018, for the airworthiness-approval certification program. These are aircraft number 2 through 5, numbers 1 and 6 being the ground-test machines, with two 777-8s later supplementing the campaign. Development plans feature three main steps in the coming three years: final-assembly start (2018) and 777-9 roll-out (2018); first flight (2019); and initial customer delivery (2020).

737 Max

As the second 787-10 flew and GE ran the 777X’s certification-standard GE9X engine, lessor Avalon was delivering the first 737 Max 8 (737-8) re-engined single-aisle twinjet to Malaysian operator Melindo Air. While four flight-test examples—dubbed 1A001 through 1A004—have finished flight trials, two larger 737 Max 9s (1D001 and 1D002) remain busy.

Continuing development is set to include the Max 8-like (but more-densely seated) 737 Max 200, which will be the low-cost variant; the smaller 737 Max 7; and the stretched Max 10, launched at the Paris Air Show in June. Each of these latest 737 variants is powered by the new CFM International Leap-1B engine, and has “advance technology” winglets and large avionics displays, among other changes.

December should see join-up of the 737-7 fuselage and wing units, production having officially begun in October with manufacture of the first wing spars in Boeing’s Renton, Washington factory.

Boeing also is “working toward firm configuration” for the Max 10 in the “coming months.” The 737-10 features a re-worked landing gear that will require additional flight-testing; the undercarriage was selected from several concepts that included different design parameters, all engineered to ensure necessary runway clearance for the longer airframe.

Boeing 737-9 flight trials are “on track to conclude by the end of 2017,” according to Boeing, certification flying having started with first flight of 1D001 in April. As much as 30 percent of earlier 737-8 testing—especially stability and control work—is expected to be repeated on this first “stretch” sub-variant.

Both fight-test 737-9s have been engaged on model-specific tests. Aircraft 1D001 is being used for autoland, avionics, flutter, and stability-and-control trials; while 1D002 has been assigned to environment control system testing.

This “fourth-generation 737” flight-test story began with first Max 8 sub-variant 1A001, the aerodynamic trials example used for flutter testing, stability and control, and takeoff performance-data verification, before its modification to operator-specific configuration and delivery to a customer. Boeing's 737-8 1A002 was used to conduct performance and production-representative engine testing, with aircraft systems testing (including autoland) work completed with 1A003.

Aircraft 1A002 also was involved in climb and landing performance, cold weather trials, and fuel-burn measurement, as well as some highaltitude testing. This machine also carried out crosswind, noise and engine water-ingestion work.

Equipped with a light flight-test instrument kit, the cabin of the fourth 737-8, 1A004, was completed with a typical airline interior layout for 300 hours of U.S. Federal Aviation Administration function-and-reliability certification flying.

747-8

Finally, Boeing said that the 747-8 does not have an active test program.