CFM says its has yet to see "any issues" linked to a manufacturing deficiency that could cause cracks on certain Leap-1A high pressure turbine (HPT) rotor stage 2 disks, and says a "limited" number of engines are affected.
The issue, caused by what the OEM describes as a "forging process deficiency," led CFM to issue an inspection recommendation in September "out of an abundance of caution," a spokesperson emphasized. Both EASA and FAA mandated the checks, requiring inspections before the affected parts accumulate 1,200 cycles, which is about six to nine months of revenue service.
CFM did not say how many total engines were affected. FAA says its directive covers seven engines.
"It was identified that a batch of high pressure turbine (HPT) rotor stage 2 disks are possibly affected by a forging process deficiency during manufacture. This may have caused undetected defects in the disk bore, resulting in a lower life capability," each regulator's directive explains.
"We haven’t seen any issues with this at all, either during ground and flight tests, or during the roughly 410,000 hours of service," the spokesperson said.
The forging issue is one of several production-quality challenges that has hit the Leap family. Earlier this year, a manufacturing quality issue affected Leap-1B low-pressure turbines, leading to a disruption in 737 Max flight testing. More recently, it revealed that coatings on composite turbine shrouds are peeling off. The issue has been found only on -1As, but Safran executives indicated it could affect -1Bs as well.