Nexcelle is creating smart nacelle systems for tomorrow’s world travel. Headquartered in Cincinnati, Ohio, USA, the company is a 50/50 joint venture of Safran Nacelles and GE Aviation’s Middle River Aircraft Systems (MRAS), which are leading suppliers of engine nacelles, thrust reversers and aerostructures. Through Nexcelle’s relationship with CFM International, GE Aviation and Safran, the joint venture brings unparalleled expertise in the design, development, production and support of integrated propulsion systems for a wide range of aircraft.
C919 LEAP-1C nacelle
Developed and produced by Nexcelle, a joint venture owned 50/50 by Safran Nacelles and MRAS (GE Aviation).
As an essential complement to the LEAP-1C engine (CFM International), the nacelle is a complex system which channels the airflow through the engine and protects it. The nacelle manages several basic functions: aerodynamics, noise alleviation, aircraft braking during landing (thrust reversers), and aesthetics.
Integrated propulsion system
The Nexcelle nacelle and the C919 jetliner’s turbofan engine form an integrated propulsion system (IPS). This IPS and the pylon (COMAC) have been designed with all the partners working in close technical collaboration on the same platform, which allows maximum optimization of the interfaces. The result is reduced weight and improved performance.
Innovative O-Duct thrust reverser
The C919 nacelle is the first to have a certified thrust reverser with an O-Duct architecture, actuated by an E-TRAS* electrical actuation system. This O-Duct architecture, which replaces the traditional two-door "D" configuration, improves aircraft aerodynamics and reduces fuel consumption by 0.5%, i.e. 300 kg per flight. It facilitates maintenance operations by enabling direct access to the engine.
Electrical Thrust Reverser Actuation System
The E-TRAS system, 100% developed by Safran, is designed and manufactured by five Group entities**. It replaces the heavier hydraulic actuation systems that are traditionally used on thrust reversers.

*E-TRAS : Electrical Thrust Reverser Actuation System
**Safran Nacelles, Safran Aircraft Engines, Safran Electronics & Defense, Safran Electrical & Power, Safran Landing Systems & Power, Safran Landing Systems
Fan cowls
Fan cowls protect the engine and its accessories.
Exhaust system
Safran Nacelles
Composed of the nozzle and the rear cone, the exhaust system serves to channel hot gases exiting the engine.
Air inlet
The air inlet channels the incoming air flow in the engine and participates in noise attenuation of the nacelle. The C919 air inlet is equipped with a deicing system that uses hot air from the engine.
E-TRAS electrical actuation system
Safran Nacelles
Thanks to synergy between several entities of the Safran group, an E-TRAS® (Electrical Thrust Reverser Actuation System) replaces the older generation of hydraulic actuation systems. Its role is to actuate the thrust reverser. Used for the first time on the Airbus A380, this ETRAS® technology has been specifically adapted for the C919. The O-Duct thrust reverser is the first in the world to have an electrical actuation system. The simplified design and electric operation of E-TRAS® provide mass reduction, an increased reliability in service, facilitated maintenance and the elimination of corrosive hydraulic fluids.
Thrust reverser
Safran Nacelles / MRAS
The thrust reverser redirects part of the air flow going through the engine towards the front, in order to create a counter-thrust that slows down the aircraft. It is used during landing to reduce the braking distance, mainly on wet, icy or snowy landing strips. The C919 nacelle is the first to have a certified thrust reverser with an O-Duct architecture ; and actuated by an electric actuation system known as E-TRAS®. The C919 uses a cascade-type thrust reverser technology with electrical actuation system: the mobile part of the thrust reverser slides to the back, uncovering the cascade vanes and pivoting the panels in the air path. The secondary flow is then deviated by the panels towards the cascade vanes, thus reversing the thrust.
An innovative single-piece architecture
While the classic thrust reverser is composed of two semi-circular doors, the C919 engines’ thrust reverser is composed of a single part attached to the engine’s forward upper portion. Seen from in front, it forms the letter "O", thus its name: "O-Duct". This innovative architecture improves the aerodynamics of the integrated propulsion system, which reduces its fuel consumption. It also increases the inner surface area with acoustic treatment.
Movable flaps

In contrast with a classic thrust reverser (C-Duct), the mechanism used to deploy the flaps and to close the secondary airpath to send the air flow towards the cascade vanes during braking is integrated in the inner wall during flight. This improves secondary air flow circulation, and thus the fuel consumption of the integrated propulsion system.
A jet engine's jewel case
The nacelle surrounds the engine and channels air flows: the primary flow (air entering the compressor to be burned in the combustion chamber, then released via the nozzle) and the secondary flow (air flowing between the engine and the inside of the nacelle). It protects the engine equipment and manages temperature deviations (down to -50°C outside the nacelle and up to +500°C inside).
Help for braking
The thrust reverser plays an essential role during landing. When activated, it reverses the flow of air in the engine, thus creating counter-thrust, which slows down the aircraft. The thrust reverser helps the aircraft to brake on wet, icy or snowy landing strips. It also helps to reduce wear on the brakes, and to decrease landing distance.
Reduce noise emissions
The nacelle greatly helps to reduce engine noise, thanks to the use of composite materials and acoustic treatment applied on its inner panels. Composite materials represent 60% of the COMAC C919 jetliner's nacelle (by mass). This helps reduce the engine's noise emissions by 50%.
Tailor-made assistance
Safran Nacelles supports C919 customers in operating their nacelles, with highly responsive after-sales support (servicing in the event of aircraft-on-ground/AOG situations, 24/7 call centers) and a complete range of custom services (advice, technical support, spare parts or nacelles, comprehensive planned and unplanned maintenance solutions). These activities rely on a global network of technical representatives, support managers and regional sales managers. They involve four distribution centers and five repair shops in the USA, Europe, the Middle East and Asia.
Tailor-made assistance
Optimised access to the engine
The C919 O-Duct thrust reverser facilitates maintenance operations, while enabling optimal access to the engine equipment, thanks to use of standard tools.
Thrust reverser with a fixed, independent, line-replaceable structure (LRU)
The O-Duct thrust reverser attached to the pylon has the advantage of having a fixed, independent structure that can be directly replaced under the aircraft wing, like any LRU (Line Replaceable Unit). This architecture ensures quick return to service for the thrust reverser in case of damage, thus avoiding replacement of the part integrating the thrust reverser system (TRAS).
The E-TRAS (Electrical Thrust Reverser Actuation System) replaces the older generation of hydraulic actuation systems in thrust reversers, and offers the following advantages: simplified design, mass reduction, simplified maintenance, and elimination of corrosive hydraulic fluids.