Boeing on Tuesday marked the first delivery of the new 737 Max 8 to launch customer Malindo Air of Malaysia with an official handover at the manufacturer’s Seattle delivery center. The first delivery to the Lion Air subsidiary comes on the same day Boeing resumed the full range of 737 Max flight test activities following approval from the U.S. Federal Aviation Administration. Boeing had restarted limited flying activities with the 737 Max on May 12, roughly a week after grounding the fleet due to a potential problem with some of its CFM Leap-1B engines.

Boeing suspended 737 Max test flights “out of an abundance of caution” on May 5, after CFM notified it of a potential “quality escape” involving low-pressure turbine discs in certain Leap-1Bs delivered to the airframer. A CFM spokesperson told AIN that the company discovered an “anomoly” in the forging process of the LPT discs in question. She added that the problem involves only one of several suppliers of the part, meaning it would not disrupt production of the engines. Although she would not identify the supplier of the problem discs, she noted that they came from the first disc supplier CFM partner Safran used in its LPT assemblies. She also noted that the suspect discs do not appear in the Leap-1A for the Airbus A320neo or the Leap-1C for the Comac C919, both of which use a larger low-pressure turbine.

Although Boeing would not comment on how many engines the suspect discs forced fellow CFM program partner GE to disassemble for inspection, Safran CEO Olivier Andries told reporters that it would take “a few weeks” to resolve the resulting logistics disruption. CFM said the inspections will involve about 30 engines.

Certified by the FAA in March, the 737 Max 8  clocked some 2,000 hours on the engines, including abuse testing and flights lasting more than nine hours. Boeing’s inspections throughout the process hadn’t uncovered any problems. “Additionally, 180-minute Etops testing completed in April required another 3,000 simulated flight cycles on the test stand before a complete inspection was conducted by CFM,” added Boeing.