On September 29, after five years of intensive flight tests and thousands of flight hours, the COMAC (Commercial Aircraft Corporation of China Ltd) C919 aircraft received its type certificate from the Civil Aviation Administration of China (CAAC). This marks China’s first trunk jetliner to achieve the most important milestones for airworthiness certification and takes the program one step closer to delivery and entry into commercial airline service.
A big part of the certification effort was the LEAP-1C integrated propulsion system developed by CFM International, a joint venture between GE Aviation and Safran Aircraft Engines. The concerted efforts of many “unsung heroes”, such as team members from CFM, who have been providing generous support since the launch of C919 program in 2009, have helped made this program a reality.
I have been fortunate to be part of the CFM team for most of my career and they have never ceased to amaze me. I believe there is not another team like it in this industry. The dedication, ingenuity, and sheer hard work every single member delivers each day has been the ‘secret ingredient’ to CFM’s long-term success.
Engine Customized for the aircraft
The heart powering C919 is the LEAP engine offering up to 15% better fuel efficiency and lower carbon emissions. Up to now, its three types (LEAP-1A, LEAP-1B, LEAP-1C) have reached more than 18,000 total orders and commitments, of which more than 5,700 have been delivered to operators worldwide.
In December 2009, COMA signed a letter of intent for cooperation with CFM International. It was also in that year that Zhong Guohua, the Aero-engine System Design and Integration Manager of CFM, joined the LEAP-1C.engineering team.
He reveals what CFM offered to COMAC was more than the engine, but an integrated propulsion system solution, including the nacelle systems as well. Such an integrated design can minimize the overall weight structure of the aircraft, thus gaining improvements in aerodynamics. In other words, the improved propulsion system is more economical and fuel-efficient, while achieving better performance.
This is the first time in China's commercial aviation history that an engine is developed based on the overall design of an aircraft." Zhong Guohua said.
To us, the most difficult part was the development and engineering flight tests, because it is 0-to-1 stage. When overcoming the challenges at this stage and entering into certification flight tests, I feel more confident.
Closed-loop under Pandemic – Together with Customer
At the end of 2019, a total of 6 compliance C919 aircrafts started flight tests at different sites all over China. The CFM team, together with COMAC began their support journey, as well.
Dang Yuhao, the flight test manager of CFM C919/LEAP-1C project cherished the vivid memories of how they completed many difficult tasks during the past five years of flight testing.
Engine in-flight thrust determination (IFTD) was one of them. This task not only validate the acceptance of the engine performance, but also reveals the economic performance of aircraft, which, to a great extent, determines the competitiveness of C919 in the civil aircraft market. Yuhao and his team often worked day and night to confirm data and solve problems to ensure the success of this task. This intensive work mode lasted for nearly half a year.
Our team members and their families have overcome lots of difficulties and gone all out to help COMAC whenever and wherever they need. We did all these for the common goal: to fully collaborate with customer for the test flight and certification of C919 so that they can be delivered to customers as early as possible!
French Factory Worked Round-the-Clock for TC schedule
Last year, Joey recalled, a spare engine needed to be sent to a France-based factory for repair. France was also under severe pandemic impact at that time, so the repair would take longer than before. To keep the certification flight test on schedule, the program team kept coordinating with US and French counterparts.
Finally, the French factory decided to work around the clock to accommodate the urgent requirement. The spare engine was sent back to China nearly 3 weeks ahead of schedule, which bought a lot of time for subsequent flight tests and certification.
"Soon after the spare parts completed customs clearance in China, we delivered them to the test site by relays." Joey said, thanks to the coordination from COMAC and customs, the clearance time of these parts was expedited, ensuring an on-time delivery. In addition to replacing parts, some engine designs needed to be optimized during the flight tests. and technical reports needed to be submitted to obtain the certification approval from regulatory authorities.
This work also needed to be coordinated and handled according to agencies’ priority. "In order to get the certification on schedule, we managed to merge and speed up certain tests while finding a way to get our application approved as soon as possible. " Joey commented.
It paid off and went beyond expectations
With the full support of CFM's team, the C919 finally got its type certificate on September 30, 2022.
The feedback CFM received from COMAC was ‘Thanks to the integrated propulsion system developed for the aircraft, the performance of LEAP-1C engine is beyond our expectations from the function reliability flight test task in July 2022.
“The C919 certification is a monumental milestone, both for China and for CFM. The relationship between CFM and China’s aviation industry has continued to evolve and flourish since the first CFM56 engines entered service there in 1985. Today, that relationship goes well beyond customer and engine manufacturer and we could not be more honored to be such an integral part of the program.