Boeing 777-9X

Boeing 777X – The Next Generation

Tim Takeoff
07.06.2019
4 pictures
6 minutes

When Boeing unveiled the 777 in 1994, no one had any idea how successful the wide-body twinjet, which was still a new concept at the time, would become. Four-engine models reigned supreme on the world’s long-haul routes. But after more than 25 years, Boeing’s cash cow is overdue for an overhaul. The Boeing 777X is following in mighty footsteps.

The 777 success story

Since being commissioned, the 777 has ushered in a U-turn in aviation, gradually banishing significantly less efficient four-engine models. At the time, it was the first aircraft to be developed entirely digitally. The completely round fuselage cross-section also distinguishes the 777 visually from similar designs.

The 777 became known not least for its engines. Although, initially, Boeing still offered a 777 option featuring Rolls-Royce engines, the majority of the more than 1,500 jets delivered were equipped with the General Electric GE90 engine. With a diameter of 3.42 metres and a capacity of up to 115,000 hp, it’s the largest and most powerful engine in the world to date. It’s so large, in fact, that an Airbus A320 fuselage could pass through it. In terms of sheer volume, the cargo version of the 777 even trumps its in-house rival, the 747F. And it’s even more economical.

Four or two – ETOPS

With approval for high ETOPS (Extended Twin Operations for twin-engine aircraft), the 777 can also operate on extremely remote routes. These were previously the exclusive preserve of the aforementioned four-engine models, such as the Boeing 747 and the Airbus A340. Authorities require simple twin-engine jets to be able to reach a diversion airport within an hour of flying time.

When crossing the Atlantic, the Pacific, the Indian Ocean or Central China, however, the density of airfields is too low. The available airports simply do not have enough equipment to serve large jets as diversion airports. Aircraft serving routes with over an hour to the nearest airport must meet significantly higher requirements. Four-engine models have, by their very nature, always led the field in this area.

The 777’s extended ETOPS approval of up to 330 minutes (5.5 hours) is due mainly to its extremely high redundancy. With the 777-200LR as an ultra-long-haul version and the 777-300ER as the workhorse of most of the world’s major carriers, the 777 is one of the most versatile aircraft families.

The 777X

After many years of deployment, not least in the modern freighter versions, it was time for Boeing to develop the 777’s successor. In November 2013, the company unveiled the 777X in response to the Airbus A350XWB. Since then, the 777X family has been expanded to include the 777-9 (414 passengers, 14,000 km range), the smaller 777-8 (365 passengers, 16,000 km range) and – assuming the demand is there – an elongated 777-10. Airlines could, in future, even use the latter to replace the capacity of the current Airbus A380.

The facts

The wings

The 777X’s wings are longer and are made of composite materials, including glass and carbon fibre. The increased wingspan results in a higher aspect ratio (ratio of wingspan to wing area) making the wings many times more efficient.

The wings are based on those of the 787, but are angled less farther back. Fly-by-wire is, of course, installed, but in an improved version. The central wing box resembles that of the “old” 777, but is reinforced with titanium, making it heavier. The wings’ considerably larger wingspan of 68.6 metres would place the aircraft into airport Category F, similar to the B747-8 or A380.

The ultimate innovation

Boeing has, however, collaborated with Germany’s Liebherr Aerospace to develop a mechanism to fold up the 777X’s wingtips once the plane is on the ground to enable it to be processed at the same gates as the 777. Folded back, the 777X’s wings shrink below the magic 65-metre mark, thus placing the plane into Category E. The US Federal Aviation Administration requires Boeing to have the highest redundancy and special procedures in place to rule out the possibility of the wingtips folding back in flight. The elevator unit has also been enlarged.

The cost of developing the wings alone accounts for two billion US dollars of the project’s total five-billion-dollar price tag.

Large displays and new technology

Boeing also uses standards from the B787 in the cockpit. Larger displays with touchscreens, as well as the controls for the folding wingtips, distinguish the 777X from its predecessor. A system similar to Airbus’s tried-and-true Brake to Vacate  enables pilots to perform optimal braking processes on the runway, allowing them to exit via the appropriate taxiway.

The centrepiece – a new engine

Building on the GE90’s success with the 777, Boeing decided to collaborate with General Electric on the 777X. The diameter of the new GE9X engine is a good 15 centimetres larger than the old GE90, and the new model will be Boeing’s sole engine option.

The aircraft’s total jet fuel consumption is a good 10 percent less than its predecessor. This converts to savings of as much as approximately 21 percent per seat and means a 16-percent improvement in overall operational costs.

The schedule

Because Boeing wanted to launch the 737 MAX before the 777X, the 777X project was postponed by about a year. At the 777X’s launch at the Dubai Airshow in December 2013, Boeing received an order from Emirates for 150 aircraft. In addition to Qatar (50 jets) and Etihad (25 jets), Lufthansa also reserved 34 aircraft, a number which was then revised down to 20. Before this reduction, Lufthansa was set to be the first airline to receive the new jet. Due to its enormous number of orders, Emirates will now receive this honour.

With the 777X’s first flight planned for summer of this year, delivery is expected to take place around the summer of 2020 – provided that there are no delays in the approval process.

Tough times for Boeing

Construction began in December 2014 with the building of a new assembly hall in St. Louis, Missouri. By the end of 2019, up to four prototype 777-9s are expected to complete Boeing’s necessary testing procedures. The official rollout of the very first aircraft on March 13, 2019 was, however, overshadowed by the crash of the Ethiopian Airlines B737-MAX three days earlier, an incident requiring Boeing to focus on new licensing procedures. You can also read more about the B737-MAX here.

So far, the production of the 777X has not been adversely affected, and Boeing faces exciting times. Not only must the 737 MAX live up to its expectations as a box office hit, but the 777X is one of the Everett, Washington-based company’s most important projects of the 21st century.

Images © Boeing

by Tim Takeoff

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