US and European aviation regulators have certificated new high-pressure turbine blades that CFM International says will help address durability troubles with Leap-1A turbofans.
CFM had said earlier this year that it intended to introduce the new blades for Leap-1As, which power Airbus A320neo-family jets, before the end of this year.
On 6 December, the Federal Aviation Administration and European Union Aviation Safety Agency “certified the updated high-pressure turbine hardware durability kit” for the Leap-1A, CFM said the same day. The new blades are “more durable” than the previous Leap-1A blades, it adds.
“This new hardware is fulfilling our promise to ensure that Leap-1A engines achieve the same level of maturity, durability and time-on-wing that our customers have enjoyed with the CFM56 product line,” says CFM chief executive Gael Meheust.
The company is now testing a blade-durability kit for Leap-1Bs, which power Boeing’s 737 Max.
CFM says it “improved and optimised the casting and cooling” of the blades and tweaked the blade tips and trailing edges. It is now producing the new blades and intends to begin installing them on new engines during production. However, in-service Leap-1As will be first to receive the improved blades, which will be installed during maintenance visits.
The engine maker, jointly owned by GE Aerospace and Safran Aircraft Engines, has been working in recent years to address problems that have kept Leaps from achieving durability targets.
Pratt & Whitney’s competing PW1100G, which is a second power option for A320neo-family jets, has also suffered durability troubles, including from a manufacturing defect that prompted the hugely disruptive and ongoing PW1100G recall.
Broadly, new generation engines like Leaps and PW1100Gs burn hotter and at higher pressures than the engines they replaced. Those conditions, while contributing to improved fuel efficiency, can lead to faster component deterioration, which has prompted complaints from buyers.
Airline customers have had particular trouble with Leaps operated in regions where dust and sand is prevalent. Those contaminants can cause Leap high-pressure turbine (HPT) blades to develop “wrinkles”, which can be a “precursor for the failure mode that our customers see in the Middle East,” GE Aerospace vice-president of engineering Mohamed Ali said in March.
Ohio-based GE tested the new blades using a “dust rig… designed to address challenges in hot and harsh environments”, it says.
“CFM worked with a team of geologists to engineer dust that mimicked what engines experience in these environments around the world. Using a proprietary dust-ingestion system, the company was able to replicate HPT blade wear that operators were seeing in the field,” CFM adds.
In April, CFM also introduced a redesigned Leap-1A reverse bleed air system. That new system “mitigates carbon build up on fuel nozzles” and reduces the “requirement for on-wing fuel nozzle replacement”, CFM said at the time. It has also been working on a redesigned reverse bleed air system for Leap-1Bs.
