When Boeing launched the 787 Dreamliner and Airbus countered with the A350 XWB, the aerospace world witnessed a new era of long-haul efficiency. Yet beneath the polished composite skins and advanced avionics, a fascinating engineering debate simmers—one that plays out in the landing gear. The 787-10 and A350-900, while competing for the same middle-of-the-market segment, feature undercarriages that differ in five critical ways. These differences are not mere trivia; they influence everything from runway compatibility to maintenance costs and even airport infrastructure planning.

Background: Two Philosophies, One Goal

Boeing's 787-10 is the stretched, high-capacity variant of the Dreamliner family, designed to seat up to 330 passengers in a two-class layout. Airbus's A350-900, the baseline model of the A350 XWB line, typically accommodates around 315 passengers. Both aircraft promise 15-20% lower fuel burn than previous generation jets, but their landing gear architectures reveal divergent approaches. Boeing prioritized commonality with the 777 and 787-8/9, while Airbus optimized for the A350's wider fuselage and higher maximum takeoff weight (MTOW). The result: five key differences that engineers continue to debate.

1. Main Gear Bogie Configuration

The 787-10 uses a four-wheel main landing gear bogie per side, inherited from the 787-8 and -9. This design distributes weight across 16 main wheels in total (including nose gear). The A350-900, by contrast, employs a four-wheel bogie as well, but with a different geometry: the wheels are arranged in a rectangular pattern that allows for a more compact retraction into the belly. Boeing's bogie is slightly longer, which affects ground clearance and rotation angle. The 787-10's longer bogie helps prevent tail strikes during high-angle takeoffs, a critical factor given its stretched fuselage.

2. Nose Gear Steering Actuation

Boeing equips the 787-10 with a dual-channel, fly-by-wire nose wheel steering system that provides up to 70 degrees of steering angle. Airbus, on the A350-900, uses a similar fly-by-wire system but limits steering to 65 degrees. The difference may seem minor, but it impacts low-speed maneuverability on crowded aprons. Boeing's greater steering angle allows the 787-10 to negotiate tighter turns, reducing the need for tug assistance. Airbus argues that its lower angle reduces stress on the nose gear structure and extends tire life. This trade-off between agility and durability is a classic engineering dilemma.

3. Brake Material and Cooling

Both aircraft use carbon brakes, but the 787-10's brakes are supplied by Honeywell, while the A350-900 uses brakes from Safran Landing Systems. The key difference lies in cooling architecture. Boeing's brakes feature a passive cooling design that relies on airflow through the wheel well, whereas Airbus employs an active cooling system that uses a fan to circulate air during extended ground operations. The A350's active cooling reduces turnaround time after heavy braking, but adds complexity and weight. Boeing's passive system is simpler and lighter, but may require longer cooling periods after aborted takeoffs. This difference directly affects airline scheduling and airport slot utilization.

4. Shock Strut Design and Stroke Length

The 787-10's main gear shock struts have a longer stroke than those on the A350-900. This longer stroke absorbs higher impact loads during landing, particularly on runways with uneven surfaces. Boeing designed the 787-10 to operate from a wider range of airports, including those with less-than-perfect pavement. Airbus, however, optimized the A350-900 for smoother runways, using a shorter stroke that saves weight and reduces retraction volume. The trade-off: the A350-900 may experience higher dynamic loads on rough runways, potentially leading to more frequent inspections. Airlines operating in emerging markets with variable runway quality often favor the 787-10 for this reason.

5. Retraction Kinematics and Wheel Well Space

The 787-10's main gear retracts inward, rotating the bogie 90 degrees to fit into a relatively shallow wheel well. The A350-900 retracts forward, with the bogie folding in a different sequence. This difference affects the aircraft's belly profile and cargo capacity. Boeing's inward retraction allows for a wider cargo hold, while Airbus's forward retraction enables a more streamlined belly that reduces drag. The 787-10's wheel well is also slightly larger, accommodating the longer shock struts and providing easier access for maintenance. Airbus counters that the A350-900's tighter wheel well reduces weight and aerodynamic penalty.

Industry Implications

These five differences have real-world consequences. For airlines, the 787-10's landing gear design offers greater operational flexibility, especially at airports with shorter runways or rougher surfaces. The A350-900's design prioritizes efficiency and lower maintenance costs on well-maintained runways. For airports, the 787-10's higher steering angle and longer shock struts may require slightly wider taxiways and stronger pavement, while the A350-900's active brake cooling demands additional ground support equipment. Manufacturers, meanwhile, use these differences to market their aircraft to specific route profiles: Boeing emphasizes versatility, Airbus emphasizes efficiency.

Outlook

As both Boeing and Airbus develop next-generation variants—such as the 787-10ER and A350-900ULR—landing gear design will continue to evolve. Electric taxiing systems and regenerative braking could soon render some of these differences obsolete. But for now, the debate between Boeing's robust, flexible undercarriage and Airbus's optimized, lightweight approach remains a fascinating case study in engineering trade-offs. For airlines, the choice between the 787-10 and A350-900 may ultimately come down to where they fly, not just how far.