CFM International, the world's largest maker of jet engines by number of units sold, said on Wednesday that testing of a new powerplant for the next generation of narrowbody passenger jets was going to plan.
CFM, a joint venture between General Electric and France's Safran , is developing the LEAP-X engine for the Boeing 737 MAX and Airbus A320neo, as well as a Chinese competitor now under development, the Comac C919.
"We are on track and on schedule for all three programs and have had no showstoppers that we can see," Chaker Chahrour, executive vice president of the Cincinnati-based engine maker, told reporters in a conference call.
CFM is the sole engine supplier for the Boeing 737, but competes with a consortium led by United Technologies' Pratt & Whitney for deals to power the Airbus A320 range.
The competition for engine sales echoes bitter rivalries between the world's two largest planemakers.
For the next generation of A320 jets due to enter service from the middle of this decade, the LEAP-X engine will compete with Pratt & Whitney's 1100G but will remain the sole available engine choice for the Boeing 737 MAX.
The arrival of new engines offering significant fuel savings has triggered a record wave of orders for the medium-haul aircraft as airlines try to contain one of their chief costs.
CFM chief executive Jean-Paul Ebanga said CFM had sold 5,000 of its LEAP-X engines on top of a similar backlog of the model installed on existing Airbus and Boeing jets, the CFM56.
"With the sales (of aircraft) in the pipeline we will see much more significant orders down the road," he added.
CFM and Pratt & Whitney both claim the edge in offering fuel savings on the 150-seat Airbus A320neo, the European planemaker's most popular model.
CFM executives said their engine would burn at least 1 percent less fuel compared with Pratt & Whitney's engine on the A320neo and at least 2 percent less on the larger A321neo.
Over time, that gap could widen to 2 and 3 percent respectively, they added.
Pratt & Whitney said on Wednesday it was confident its engine would burn less fuel and do better on noise, emissions and cost.
"This is backed up by more than 5,000 hours of rigorous testing across the PurePower PW1000G engine family, including more than 500 hours of flight testing," a spokeswoman said by email.
(Reporting by Tim Hepher; Editing by Mark Potter and Elaine Hardcastle)