COMMERCIAL BOEING 787-10 DREAMLINER
Mark Broadbent profiles the Boeing 787- 10, the third Dreamliner variant
The Boeing 787-10 is the largest and longest variant of the three-member 787 Dreamliner family. The variant was launched during the Paris Air Show in 2013. The initial 787-10 flight test aircraft, N528ZC (c/n 60256), rolled out from Boeing’s North Charleston plant in South Carolina, the sole production site for the variant, in January 2017 and undertook its first flight on March 31, 2017. This jet and two other flight test aircraft, N548ZC (c/n 40929) and N565ZC (c/n 60257), accumulated about 900 test hours undertaking the 787-10’s flight and certification testing campaign during 2017 to ensure the 787-10 met the manufacturer’s internal requirements and US Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) certification requirements. Certification from the FAA was awarded on January 19, 2018, with approval from EASA following on February 28, 2018. The initial customer example, 9V-SCA (c/n 60253), was delivered to launch operator Singapore Airlines (SIA) in March 2018, the airline putting it into service on April 3, 2018. By August 2019, 173 examples of the 787-10 had been ordered, with 31 delivered.
What is the 787-10 designed for?
The main aircraft manufacturers off er diff erent aircraft and/or variants of the same type with complementary seating, payload and range performance characteristics to cater for diff erent needs across the widebody twinaisle airliner market. At the lower end of the widebody market are the Boeing 787-8 and Airbus A330-800, which with around 250 seats are designed to cater for airlines’ lower-capacity and marketopening requirements. The 787-9 and A330- 900 sit in the 250–300 seats segment of the market, with the 777/777X and A350-1000 optimised for 350-plus seats. The 787-10 sits between the 787-9/A330- 900 and the 777/A350-1000 in the segment for 300 to 350 seats. Its primary head-to-head competitor is the A350-900. The 787-10 is optimised to carry 330 seats in a typical twoclass layout (32 in business class and 298 in economy) or up to a maximum of 440 seats alleconomy. Its revenue cargo capacity is 6,722ft3 (191.4m3). The aircraft can operate routes of up to 6,430 nautical miles (11,910km) range. The 787-10 cannot fly as far as its Dreamliner stablemates (the 787-8’s typical range is 7,355 nautical miles/13,620km and the 787-9’s is 7,635 nautical miles/14,140km), but it is not intended to. The 787-10 was expressly designed to off er airlines the ability to put more capacity on their medium to long-range routes where demand characteristics justify it.
The variant’s 330 seats two-class compares to 242 seats two-class (359 single-class) on the 787-8 and 290 seats two-class (406 single-class) on the 787-9. The 787-10’s larger size also means it carries more revenue cargo. According to Boeing’s latest Airplane Characteristics for Airport Planning document, the 787-10’s underfloor cargo volume provides space for 22 LD-3 containers (each sized at 158ft3/4.5m3) in the forward compartment and 18 in the aft compartment. This total of 40 LD-3s is four more than the 787-9 and 12 more than the 787-8. There is also 402ft3 (11.4m3) volume in the bulk cargo compartment. Total cargo capacity is 15% more than the 787-9 and 41% more than the 787-8.
What is different about the 787-10?
A longer fuselage is the most obvious difference between the 787-10 and its 787-8 and 787-9 stablemates. At 224ft (68m) in total length, the 787-10 is 18ft (5.4m) longer than the 206ft (63m) 787-9 and 38ft (11.5m) longer than the 186ft (57m) 787-8. All the Dreamliner variants share the same 197ft (60 m) wingspan, 56ft (17m) height and 18ft 10in (5.74m) fuselage cross-section. The 787-10 is technically a ‘double stretch’ of the 787-9; Boeing took the 787-9’s fuselage and added five frames forward of the wing (which make up 10ft/3m of the 18ft/5.4m extra length) and four frames aft of the wing (which make up the other 8ft/2.4m). The variant has a maximum take-off weight of 560,000lb (254,011kg), the same as the 787-9. However, a longer fuselage creates more surface area and therefore higher structural loads, necessitating local strengthening on certain areas of the lower empennage. The extra length also results in a crucial difference between the 787-10 and the other variants: a semi-levered landing gear. The 787-10’s main landing gear truck has an additional actuator that locks out and means the pivot point around which the aircraft rotates on take-off is different. A 787-10’s pivot point is around the aft wheel of the landing gear truck rather than the midpoint, as on the other Dreamliners. Changing any part of the structure on an aircraft for a new variant obviously changes the model’s handling characteristics, so Boeing had to adjust the Dreamliner’s fly-by-wire flight control system (FCS) control laws accordingly
”FoVMS will be active in certain parts of the flight envelope when the flaps are retracted.” FAA
The 787-10 features a specific control law that if it detects a potential tailstrike commands the elevators to generate nosedown pitch to adjust the fuselage’s attitude, which increases the clearance between the fuselage and the runway and the safety margin for rotation and flare. A priority in flight testing the variant was assessing the longer fuselage’s impact on the aircraft’s handling and control. Take-off and landing performance tests were carried out at Edwards Air Force Base in California and crosswind landing trials at Gander International Airport in Canada to validate the variant’s performance.
What is the FoVMS?
Another significant difference between the 787-10 and the other Dreamliners is a flaps up vertical modal suppression system (FoVMS) As explained in an FAA document published on the US Federal Register detailing the special-condition justification from Boeing for the FoVMS, the 787-10’s longer fuselage degraded the flutter performance of the Dreamliner wing, nacelle and body. The traditional ways of dampening flutter to an acceptable margin are either to increase the torsional stiffness of the wing or add ballast weights into the design of the wingtips. The FAA wrote in its document that Boeing rejected these options because it felt they, “do not meet [the company’s] business objectives”. The company instead proposed introducing a new control law for the normal mode of the 787-10’s primary FCS to satisfy the flutterdamping margin requirements.
The paper explains: “The FoVMS system will be active in certain parts of the flight envelope when the flaps are retracted. The FoVMS system is a feedback-control system that adds damping to the system’s 3Hz mode by oscillating the elevators symmetrically. When the elevators are expected to be ineffective due to blowdown or other limitations, the flaperons are applied to augment or supplant elevator-control input.” A further important difference between the 787-10 and its Dreamliner stablemates is the larger, longer variant’s more powerful engines: either General Electric (GE) GEnx- 1B76s or Rolls-Royce Trent 1000 TEN (Thrust, Efficiency, New technology) turbofans. According to the manufacturer’s datasheets, the GEnx-1B76 variant on the 787-10 provides 76,100lb (338kN) take-off thrust and the Trent 1000 TEN generates 78,000lb (347kN) takeoff thrust compared to the 74,100lb-thrust (329kN) GEnx/Trent 1000 variants on the 787-9 and the 69,800lb (310kN) variants on the 787-8.
The Trent 1000 TEN uses technologies from the Trent XWB engine developed for the A350, specifically a scaled-down intermediate pressure and high-pressure (HP) compressor first developed for the the A350-900’s Trent XWB-84 and the HP turbine architecture first developed for the A350-1000’s Trent XWB-97. Other diff erences between the Trent 1000 TEN and the latest Trent 1000 Package C engines on the 787-8 and 787-9 are a modulated air system, an increased use of composites, redesigned external systems, a new external gearbox and an updated engine control system. Rolls-Royce says the Trent 1000 TEN provides a 2% fuel burn improvement on earlier Trent 1000s.
What is the 787-10 made from?
Although the 787-10 features those more powerful engines, the FoVMS, the semilevered landing gear and the additional FCS control law, the diff erences between the aircraft and the other Dreamliner variants are minimal and deliberately so, because structural and systems commonality means operators can retain the same procedures for maintenance and crew training and common spares holdings. Boeing says there is over 95% commonality in part numbers between the ‘Dash Ten’ and the other Dreamliners. As per the other 787s, advanced materials make up more than 65% of the 787-10’s structure by weight, with carbon fibre composites accounting for nearly 50% and titanium for 15%. Other materials in the aircraft include aluminium or aluminium lithium (20%) and steel (10%). Carbon laminate structures, produced by forming carbon fibre infused with a resin into a tape before lamination, are used in the fuselage, vertical and horizontal stabilisers, wing covers and wing leading edges. There are carbon sandwich structures, produced by attaching two thin but stiff skins to a lightweight core, in the vertical and horizontal stabilisers and wings.
How does the electrical system work?
Along with this extensive use of advanced materials, another key feature in the 787 Dreamliner is its electrical architecture. The traditional method of powering secondary systems is to divert bleed air from the engines to generators and the auxiliary power unit (APU) for pneumatic power. Although it is incorrect to say the 787 is totally bleedless, as bleed air is still used for certain functions such as some anti-ice systems and pressurising hydraulic reservoirs, most of the functions that usually rely on bleed are on the Dreamliner driven instead by electrical power.
Boeing says the architecture reduces maintenance costs and improves engine efficiency, because the 787 does not feature extensive pneumatic components such as ducts, valves, heat shields, starters and compressors. On the Dreamliner, generators on each engine and the APU are directly connected to the engine gearboxes that drive electric motors that distribute power to the aircraft’s electrical/electronics (E/E) bay and remote power distribution units (RPDUs). In turn, the functionality of critical systems on the 787 is diff erent from other aircraft. To give some examples, the converters used for engine and APU start and the hydraulic pumps used to support flight controls, landing gear, thrust reversers and control surfaces are driven by electric motors. Wing antiice protection, traditionally provided by discharging hot bleed air into the wing through a valve, on the 787 is provided by the electrical system energising heating blankets bonded to the interior of the protected slat leading edges, while the Dreamliner’s brakes are electrically rather than hydraulically actuated.
Electrical actuation enabled Boeing to eliminate physical circuit breakers in the flight deck. According to the manufacturer, just 13 line replaceable units are needed to provide the full complement of flight deck display, communication, navigation and surveillance equipment. Boeing did not have to do anything drastic to this established architecture despite the 787-10’s larger size, the work being to tune up the system to meet the extra power demands by using the inherent margin designed into the system to uprate the capability of the generators, E/E bays, RPDUs and the wiring.
”Airlines continue to pay for range they don’t need.” Teal Group
What is the 787-10’s flight deck like?
The Boeing 787 Dreamliner flight deck was designed to be both innovative and off er extensive commonality in layout and operating procedures with previous Boeing flight decks, especially the 777 (which enabled the manufacturer to pursue a common type rating between the two and minimise training time).
Boeing retained its wheel-and-column control layout and the flight control system uses some of the Triple Seven’s flight control laws, the aircraft exhibiting similar handling characteristics. Cockpit displays, switches and controls were deliberately positioned like a 777’s, and pre-flight procedures and checklists are similar.
Boeing says the commonality means pilots already qualified on the 777 can transition on to the 787 in as little as five days, maximising crew-rostering flexibility for airlines using both aircraft. Pilots with no experience in a Boeing flight deck will need 21 days of training, the company says.
The 787-10’s cockpit includes five multifunction displays (MFDs), dual head-up displays (HUDs) and the dual electronic flight bags (EFBs). The MFD screens are each 15.1in (383mm) diagonal liquid crystal displays supplied by Collins Aerospace.
The two outboard MFDs show primary flight display information combined with an auxiliary display consolidating frequently referenced information such as the flight number, radio frequencies and the aircraft transponder code. The lower portion of the auxiliary display shows datalink messages, controller-pilot datalink communications and digital automated terminal information.
The MFDs can be split into independent formats or configured to provide a single large navigation map. Pilots can select other MFD formats, including synoptic displays showing data for major systems, the electronic checklist (ECL) and an electronic control display unit interface, enabling them to tailor how they want the MFDs to present information The triple-redundant flight management system (FMS) is produced by Honeywell, which supplies all the navigation, maintenance and crew information systems, electronics and FCS on the aircraft.
Among the systems to aid crew situational awareness are integrated approach navigation, an enhanced vertical situational display (which provides a graphic rendering of approaching terrain and a picture of the FMS-calculated vertical flight profile), a ground moving map, integrated surveillance systems providing weather radar, a transponder, a traffic collision avoidance system, and ground proximity functionality. There is redundancy to support automatic dependent surveillance-broadcast and dual HUDs showing the pilots the standard information needed to fly the aircraft.
The Dreamliner was initially certified to operate up to 180 minutes’ flying time away from a landing site, but additional extended-range operations capabilities allow 787s to be operated up to 330 minutes flying time away.
Several 787 operators AIR International has spoken with in recent years, such as Virgin Atlantic and TUI, have cited the ECL as a particularly useful feature of the Dreamliner’s flight deck. The ECL is useful not just for replacing paper checklists, but also in minimising the omission of checklist items. This is because some items in the ECL are closed loop, which means the system automatically checks if a switch or lever is in the proper position. This means pilots can’t leave anything out, the ECL notifying the pilots if there is an issue that requires attention.
The 787 has dual Class 3 touchscreen EFB compatibility. A further benefit of the flight deck’s design is accessing information from the FMS using the EFBs. An onboard performance tool (OPT) enables flight and maintenance crews to carry out real-time calculations based on current weather and runway conditions to calculate the take-off and landing numbers and weight and balance information. The system corrects for pressure variations, runway conditions, engine bleeds and Minimum Equipment List variations.
Rather than performing calculations using manuals, the crew enters all the information about the takeoff and landing, take-off weights and fuel weights and weather data into the system, with the OPT then generating optimal thrust rating and flap settings for the crew to use. Moreover, the system will tell pilots if there’s an error, for example if erroneous weight information is entered.
The dual HUDs of course provide pilots with flight information in their line of sight. Autothrottle capability and asymmetry compensation through the flight controls means engine-out handling is straightforward for the pilots.
The electrical system also contributes to one of the key differences about the 787 the manufacturer and airlines like to emphasise: the feel of the cabin. The environmental control system controlling air conditioning and pressurisation uses electrically driven adjustable speed motor compressors, which compress air (drawn aboard from outside the aircraft via inlets) through low-pressure airconditioning packs. Another important design feature of the 787 is its battery system. The 787 has two primary rechargeable lithium ion batteries: an APU battery housed just behind the wings in the aft E/E bay and a main battery in the forward E/E bay. The 787-10 of course has the features – including insulators around each battery cell, wire sleeving and upgraded wiring, fasteners, stainless steel enclosures and venting systems –introduced to the Dreamliner as fixes for the battery issues that caused incidents in early 2013 on Japan Airlines and All Nippon Airlines 787s and grounded Dreamliners for months.
How is a 787-10 built?
Production of the 787-10 takes place exclusively at North Charleston, South Carolina, in a four million ft2 (371,612m2) facility. As with the 787-8s and 787-9s assembled at Everett, there is a complex international supply chain involving Boeing and partners across North America, Europe and Asia. Section 41, the forward fuselage (including the nose and cockpit) and the wing’s fixed and movable leading edges are produced by Spirit AeroSystems in Wichita, Kansas. Many sections are produced in Nagoya, Japan, by different suppliers. There, Kawasaki Heavy Industries produces Section 43 (mid-forward fuselage), Subaru manufactures Section 45 (wingbox), Mitsubishi Heavy Industries produces the wing and its fixed trailing edges, and Kawasaki Heavy Industries manufactures the main landing gear wheel well.
Leonardo at Grottaglie, Italy contributes Sections 44 and 46 (centre fuselage). Boeing Aerostructures Australia in Melbourne manufactures the movable wing trailing edge, Boeing Fabrication in Salt Lake City, Utah and Frederickson, Washington the tailfin (although the rudder comes from the Chengfei Commercial Aircraft Company in China) and Boeing Fabrication in Winnipeg the wing/body fairing and landing gear doors. The wingtips, flap support fairings and the Section 48 aft fuselage section come from Korea Aerospace at Busan, South Korea. The landing gear is manufactured by Safran Landing Systems in Toronto, Canada, the passenger doors by Latécoère in Toulouse, France and the cargo access doors by Saab in Linkoping, Sweden. Boeing’s four in-house 747-400LCF Dreamlifter transport aircraft bring the wings and mid-forward fuselage from Nagoya, the centre-fuselage Sections 44 and 46 from Italy, and Section 41 from Spirit.
Once all these parts are at North Charleston, Sections 43–46 are joined to centre-rear and aft fuselage Sections 47 and 48, which are produced at North Charleston by Boeing South Carolina. Before the mid and aft fuselage sections are delivered to final assembly, the sections receive coats of paint to protect the composite parts of the structure from ultraviolet light. Final assembly sees 787-10 advance through five diff erent stages. At position zero, the wings are joined to the mid-body. Position one sees the forward and aft fuselage sections joined to the mid-body, the addition of the tail and installation of the floor, landing gear, hydraulics and electrical systems (the fuselage sections arrive at final assembly lines preinstalled with wiring). Position two sees the passenger seats installed, the aircraft powered on and achieve weight on wheels. Position three sees engine installation begin, along with the production tests and the cabin pressure tests. In position four, engine and interiors installations and electrical, hydraulic and mechanical system testing are all completed. Aircraft are then taken to a 396,208ft2 (37,790m2) facility where the aircraft is painted in one of two bays. This precedes the usual process of delivering an airliner: essential checks on the fuel system, pumps, valves, tanks, hardware, APU, compass calibration, engine runs and assessments of tyres, shock struts, hydraulic fluids and cabin systems functionality before the aircraft goes to flight test and, eventually, customer acceptance and handover.
What is the Trent 1000 TEN engine issue?
Operators of 787-10s have faced disruption recently, because routine inspections on Trent 1000 TEN engines powering SIA aircraft led to the discovery of premature deterioration in the high-pressure turbine (HPT) blades in some powerplants. Rolls-Royce said: “A small number of these engines have needed to have their HPT blades replaced earlier than scheduled.” The company added the aff ected parts were on engines that had, “experienced a higher frequency of flights at the upper end of their operating range”. Rolls-Royce said it worked with regulatory authorities to establish a plan for inspecting the remaining fleet of Trent 1000 TENs. What the company calls a “new accelerated inspection regime” is in place, supported by an EASA directive, to “confirm the health of the Trent 1000 TEN fleet over the next few months”.
A statement said: “Since the entry into service of the Trent 1000 TEN, Rolls-Royce has communicated to airlines that the HPT blades in these engines would have a reduced life. As a result, our engineers have already been developing, and are currently testing, an enhanced version of this blade. We expect to start incorporating enhanced blades into the Trent 1000 TEN fleet in early 2020.” The Trent 1000 TEN issue has only added to the negative headlines around the Trent 1000. The Trent 1000 Package B and Trent 1000 Package C on the 787-8 and 787-9 have suff ered their own durability issues, forcing redesigns and fixes. More widely, a report by The Post and Courier newspaper published in early August said it had seen surveys from a number of 787-10 customers complaining about production standards on jets coming from North Charleston. The report said United had identified 20 production issues on inspecting a 787-10 in April, with American Airlines and Etihad Airways also identified as carriers that have raised concerns about quality control. Singapore Airlines and KLM have also found issues on their aircraft, the report said.
How are airlines using the 787-10?
The 787-10 provides a replacement for ageing medium to long-haul aircraft with 300 to 350 seats, namely the legacy A330 variants and the 777-200ER. Boeing says the aircraft provides superior operating costs: 25% less fuel per seat than those aircraft, as well as 10% than the current competition (i.e.the A350-900). Air New Zealand told AIR International the 787-10’s performance was “fundamental” to its evaluation process and its eventual decision to order eight examples to replace its 777-200ERs and join its 787-9s. The airline said: “We’ve chosen the 787-10 for its unrivalled fuel efficiency and carbon saving benefits.”
Most 787-10 customers are of course the large network airlines such as United, SIA and British Airways who already operate the 787-8 and/or 787-9 and for these carriers the largest Dreamliner gives extra capacity to core markets with large demand so they can maximise revenues. The largest carriers also value right-sizing for each route: the ability move aircraft around their network to account for changing patterns in passenger demand. For example, if a route started with a smaller-capacity 787-8 saw increased demand, an operator could switch the smaller variant for a 787-10 to capture the higher demand. Alternatively, if demand dropped, an airline could instead substitute the larger variant for the smaller jet to serve the route, enabling the operator to keep the service, but do so more costeff ectively, therefore freeing-up the ‘Ten’ to do something else. This, and the shared type certificate that enables Dreamliner pilots to switch between the diff erent size models and systems commonality between the 787 variants that creates standardisation (therefore lower costs) in maintenance, spares, cabin configuration and emergency equipment, means the diff erent 787 variants give an operator flexibility.
What are the 787-10’s sales prospects?
When the 787-10 was launched in 2013, Steven Udvar-Hazy, the Chief Executive of the Air Lease Corporation, which has so far ordered 25 787-10s, commended the variant’s “ideal size, capabilities and economical operating costs”. However, since the jet’s launch, Boeing has attracted just 173 orders for the variant. Although many factors influence aircraft purchasing – airlines’ future fleet planning and the timescales for these requirements, production availability, commonality with existing aircraft and wider macroeconomics influencing market conditions and fuel prices – less than a couple of hundred orders in more than six years is a slow take-up. It is a figure some way down on the variant’s headto- head competitor, the A350-900, which at the time of writing had 713 orders.
A question mark hovers over the 787- 10’s largest single order. In November 2017, Emirates used that month’s Dubai Air Show to announce a purchase commitment for up to 40 examples, stating a targeted first delivery date in 2022. However, the commitment has not been firmed up. The Gulf carrier’s annual report for 2017-2018 listed the 787-10 order as ‘authorised but not contracted’. The airline’s latest fleet plan revealed in its 2018/19 annual report issued in May 2019 omits the order completely, the plan instead showing only the A330-900s and A350-900s for which Emirates has signed commitments. According to Leeham News and Analysis, Emirates reportedly feels the 787-10’s engines are underpowered for the very hot environment of Dubai. With the airline weighing up its Boeing orders as a whole, however, including the future of its 150-aircraft order for the 777X, an order for 787-10s might not be totally out of the picture just yet. With the Asia-Pacific region having plentiful passenger numbers, the region seems an especially natural fit for the 787-10 given its positioning as a high-capacity hauler on established trunk routes. Boeing will hope the recent decision by Korean Air Lines to order ten 787-10s (first announced as a purchase commitment during the Paris Air Show before being firmed a month later) and the Air New Zealand order are signs of interest in the variant from the region.
Richard Aboulafia, Vice-President Analysis at the Teal Group consultancy, thinks the A350-900 might have the edge on the 787-10 in certain aspects. Observing that the A350-900 off ers more range (8,100 nautical miles/15,000km compared to the 787-10’s 6,430 nautical miles/11,910km capability), he noted: “Airlines continue to pay for range that they don’t necessarily need,” which, he thinks, will create “a 40-60 market split in the 300-seat segment between the 787-10 and A350-900, in favour of the Airbus jet”. The A350-900 might have greater range, but longer-range aircraft obviously take off with more fuel, so its operating empty weight (OEW) is higher at 142,400kg (314,000lb) compared to the 787-10’s 298,700lb (135,500kg). Analysts say this, the aircraft’s larger wing and more powerful engines mean the A350-900 has higher drag and therefore fuel burn when flying the same payload over a route. Aboulafia said: “The 787-10 looks like a fantastic performer from an economics standpoint, and a terrific 777-200ER replacement.” The result is each aircraft is likely to be used for slightly diff erent tasks in the 300–350 seats segment: the Airbus for routes that require range, the Boeing for those that require payload. It seems there could be a continuation of the situation that emerged in the 1990s when the 777-200ER and A330-300 split the 300-350 seats market segment, one aircraft proving most optimal for some tasks, the other aircraft most optimal for others. Meanwhile, more 787-10s are entering service. Deliveries of further aircraft to existing operators United and SIA are ongoing and both EVA Air and KLM recently received their initial examples, the latter’s first jet, PH-BKA (c/n 42485), specially painted to mark the carrier’s forthcoming centenary. AI
”We’ve chosen the 787-10 for its unrivalled fuel efficiency.” Air New Zealand
