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boeing Engine manufacturer working to certify world’s largest twin-engine jet for service next year GE Aerospace is currently working to resolve the stability issue identified in January. Like the jet itself, the GE9X powerplant for aircraft is the world’s largest and most powerful engine designed for commercial aircraft.
That said, the engine’s design and operation’s ability to deliver unprecedented levels of power may be due to cracks recently discovered in the engine’s mid-seal. Seals are located between the turbine stages with the function of ensuring airflow stability throughout the engine, which in turn affects power transmission and operating efficiency.
Cracks in engine middle seal
According to FlightGlobal, the issue was first discovered earlier this year in January. Boeing 777-9 As part of a routine visit, the test aircraft was taken to the workshop and cracks were identified. Additionally, the manufacturer, GE, inspected and evaluated the engine itself and confirmed that there were cracks in the engine. GE9X The engine’s intermediate seal was cited as a potential durability issue.
The mid seal is a critical component within the engine system, located between the turbine stages of the engine to ensure reliable airflow throughout. Any cracks found could potentially be the result of the component reacting to its operating environment. Considering that this part is located inside the core of the world’s largest and most powerful commercial jet engine, it will experience higher temperatures and pressures than any other engine.
While this is a setback, it is also not uncommon for new designs to undergo various minor upgrades and changes over the years in response to unexpected developments that may arise during operation. Additionally, it is worth keeping in mind that although the engine is not currently flying commercially, the current design was certified in 2020.
What does this mean for the engine and the aircraft?
As noted above, the engine manufacturer discovered the root cause of the problem, and GE Aerospace subsequently confirmed in its April 2026 first quarter earnings call that a fix is now underway. According to the performance presentation transcript, the CEO personally confirmed that parts modification is currently in the final stages, and detailed information about this was transparently communicated to Boeing and Boeing. Federal Aviation Administration.
It was also stated that the manufacturer is currently modifying its own tooling while increasing production from certain suppliers for parts that require modification. Of course, the modifications will require regulatory approval, but if the modifications are approved, they could be implemented in all future produced GE9X engines. Devices already produced will probably have to undergo modifications. GE Aerospace CEO H. Lawrence Culp commented on the impact on the 777-9’s certification schedule:
“As Boeing stated, we believe the certification plan communicated to our customers is on track. There are no changes to the schedule.”
GE9X is the world’s most powerful engine
The GE9X is a power plant that began testing in 2016 and is the only engine option for the upcoming Boeing 777X family. With a front-of-engine fan measuring 134 inches (11.2 feet/3.4 meters) in diameter, it is physically the largest turbofan in the world. In fact, the engine is larger than the fuselage of a Boeing 737.
In this case, the massive size of the engine and front fan is directly tied to the power plant’s ability to deliver higher bypass ratios than other engines, which in turn delivers more power while operating with better fuel efficiency. According to GE data, the table below details the engine’s technical specifications.
GE9X Technical Specifications | |
|---|---|
fan diameter | 134 inches (11.2 feet/3.4 meters) |
Number of fan blades | 16 blades designed using advanced composite materials |
thrust | Rated 110,000 lbs | Up to 134,000 pounds. |
bypass ratio | 10:1 |
Marketing Efficiency | Fuel consumption is 5% lower than other dual-aisle aircraft. 10% lower than the previous generation 777 aircraft. |
Compared to these numbers, the stark difference in engine power becomes apparent when considering the smaller engines that power the latest generation of widebody jets on the market. Rolls-Royce Trent 1000 or GEnx-1B boeing 787 The family can only produce up to 78,000 lbs and 76,100 lbs of thrust respectively, while the Rolls-Royce Trent XWB-97 Airbus A350-1000 It can deliver up to 97,000 lbs of power.
That’s not the first hurdle for power plants.
The engine received FAA certification in 2020, but was originally planned for certification in 2018. But over the past six years, the engine program has faced several challenges along the way. Some of these challenges were other durability issues, such as the discovery in 2019 that the stator vanes of the high-pressure compressor within the engine were wearing at a faster rate than expected.
Additionally, in 2022, flight testing of the 777-9 was temporarily suspended for two months due to abnormal temperature alerts in the aircraft’s engines. Moreover, in 2024, Boeing was forced to ground its entire 777-9 test fleet after discovering a defect within the engine’s thrust link. These linkages essentially transfer thrust from the engine to the airframe, and to counteract the associated vibrations, the aircraft manufacturer had to make structural changes that resulted in a five-month grounding.
Despite these issues, it is worth keeping in mind that the GE9X is indeed a new engine that has been certified, but has not yet entered commercial service. It is common to experience a variety of obstacles with new technologies and designs, especially when the product is made from new or advanced composite materials. This can often lead to unexpected long-term reactions when exposed to high levels of temperature, pressure and other aspects of operation.
Powering the upcoming 777X family
The 777X is designed as the next generation of Boeing’s popular Boeing 777 family of aircraft, one of the most popular wide-body jets in aviation history. GE9X will be the exclusive engine option for all three variants of the aircraft family. The aircraft type was supposed to enter commercial service in 2020, but the 777X has not yet been certified due to a series of certification delays and quality control issues faced by Boeing related to the grounding of the 737 MAX.
The most popular model of the 777X series is the largest model, the Boeing 777-9, followed by the freighter model Boeing 777-8F, and the small passenger model Boeing 777-8. The 777-9 is scheduled to be the largest twin-engine airliner capable of high-capacity flights on long-distance routes. As per data published by Boeing, the table below details the technical specifications of the three 777X variants.
Boeing 777X variants | 777-9 | 777-8 | 777-8F | |
|---|---|---|---|---|
volume | 426 (2 classes composed) | 395 (2 classes composed) | 224,000 pounds (112 tons) | |
range | 7,285 nautical miles (13,500 km) | 8,745 nautical miles (16,190 km) | 4,410 nautical miles (8,167 km) | |
engine | GE9X | |||
wingspan | folded tip | 212 feet, 9 inches (64.9 meters) | ||
tip extension | 235 feet, 5 inches (71.8 meters) | |||
fuselage length | 251 feet, 9 inches (76.7 meters) | 232 feet, 6 inches (70.9 meters) | ||
The first of the 777-9s is scheduled to be delivered to Lufthansa customers in 2027, and as noted above, GE Aerospace does not expect durability issues related to the engine mid-seal to have a negative impact on aircraft deliveries. The 777X has an order backlog of more than 600 aircraft, so the type remains important to operators such as: 
lufthansa and 
emirates airlinesBecause this means not only fleet growth, but also vehicle replacement, which is important for these customers.
GE9X-based aircraft to replace older quadjets
To understand why the 777X needs new custom engines, it’s important to understand the role the 777X will play when it comes to market, especially the 777-9 variant. The 777X is designed not only to replace the previous generation 777, but also to replace the world’s largest aircraft such as the Boeing 747 and the Airbus A380, of which larger aircraft are being built by then.
With this focus, Boeing needed to ensure that the replacement design was in line with current market trends and suited to a market where sustainability is becoming increasingly important. Therefore, new wide-body aircraft should ideally have a twin-engine design. As such, the 777-9 is the result of combining a high-capacity widebody fuselage with two newly developed engines that deliver more power than any aircraft engine currently on the market.
Although the airframe does not have the capacity of the A380, the 777-9 offers similar capacity to the Boeing 747-8 while offering better operating efficiency and fuel savings due to its twin-engine design. While the aircraft’s design certainly plays a role in the jet’s fuel efficiency and economy, the biggest contribution to the 777X being an efficient jet will be its powerful GE9X engines.
