Months ahead of a scheduled entry into service, CFM International is incorporating a durability upgrade for the family of Leap engines selected to power Airbus, Boeing and Comac narrowbodies.
The upgrade package will extend the time-on-wing of the Leap engine beyond the estimated seven-year cycle between shop visits already promised, CFM says.
CFM reblades the three-stage low-pressure compressor with a refined geometry that better resists deterioration and improves clearances between the blade tips and the surrounding seal.
The enhancement will raise the Leap engine’s time on wing to an interval “more in line with what customers are seeing with their mature CFM56 fleet”, CFM says. Actual interval periods will depend on how the engines are used, so CFM declines in this case to release numerical estimates of the improved durability.
The CFM56 sets a high-bar for time-on-wing performance. In 2012, German airline TUIfly celebrated a record-breaking, 13-year time-on-wing engine, logging more than 50,000h on a Boeing 737-800. Two years earlier, CFM had announced the average time on wing of the CFM56 fleet before a first shop visit is 30,000h.
CFM has previously offered reblading upgrades on the CFM56 engine that the Leap engine family replaces on Airbus and Boeing single-aisles. The Tech Insertion programme in 2007 rebladed the nine-stage high-pressure compressor with 3D airfoils.
Combined with “modest” improvements to the combustor, the Tech Insertion programme – launched 25 years after the type entered service on the 737 Classic fleet — extended durability by 2,500 cycles and reduced fuel burn by 1%.
The Leap-1B will enter service with the new blade layout for the low-pressure compressor with the first 737 Max 8 delivered to Southwest Airlines in the middle of next year, unless Boeing accelerates the delivery.
The same upgrade will be available on the Airbus A320neo by mid-2017, CFM says, or about a year after the type enters service. A retrofit will be offered to airlines that receive A320neos with Leap-1A engines before the upgrade is available.
The reblading is the second acknowledged design change on the Leap engine family. Last year, CFM replaced the abradable liner in the high pressure compressor with a new material after dissatisfaction with the original design.