EXCLUSIVE-Jet engine maker CFM studies plan B for next fuel-saving design, sources say

French-US jet engine maker CFM is ​studying a more conventional "advanced ducted" engine design alongside ​its preferred option for a ‌radical open-fan ​concept for future jets, as the industry debates fuel-savings and lower emissions, industry sources said.

The venture co-owned by GE Aerospace and France's Safran has ‌been championing an open-rotor engine, featuring a large exposed fan instead of a traditional casing, as the most efficient and environmentally friendly architecture for the next series of Airbus and Boeing jets. It says this would ‌generate fuel and emissions savings of 20% under a widely publicised research programme called RISE.

But it ‌is also looking in a more structured way than previously reported at a design where the fan would be contained inside a shell similar to casings on current engines. Experts say such designs save less fuel but can be more ⁠adaptable. The choice ​of technologies has potential ⁠implications not only for the efficiency of aircraft entering service around 2040, but the commercial strategies of Airbus and Boeing.

The project ⁠to study the alternative architecture came to light in a Safran employee's job description seen by Reuters. The employee's ​duties include work on future civil and defence projects, including the "Open Fan" and a separate, unpublicised ⁠project called "Advanced Ducted-Large" or ADL.

Three industry sources confirmed that CFM is working on "advanced ducted" architecture under RISE, which targets ⁠a cluster ​of technologies ahead of any specific engine design. Safran and GE both declined to comment. The French company is due to report earnings on Friday.

CFM and its two shareholders have consistently said ⁠they are ready to provide whatever engines planemakers want and have never ruled out choosing a more ⁠conventional design, even as they ⁠tout the benefits of the open-bladed architecture. But the emergence of a separate code name is the first tangible sign that the alternative engine design is ‌being taken seriously ‌enough to warrant standalone attention.