Seattle

Boeing Co. resumed flights of its new 737 Max jetliners on a limited basis on Friday, setting the stage for the first commercial delivery after a potential engine flaw temporarily grounded the single-aisle aircraft.

Regulators cleared the planes to fly as long as they’re powered by spare engines that don’t include the possibly defective part, Boeing spokesman Doug Alder said Friday. Supplier CFM International, a joint venture of General Electric Co. and Safran SA, alerted the plane maker late last week to a manufacturing quality problem with low pressure turbine discs in the Leap engines.

Boeing is racing to inspect the engines and meet delivery commitments to Indonesia’s Lion Mentari Airlines, the largest Max customer. The Chicago-based plane maker would need to hand over the first of the upgraded jets to Lion affiliate Malindo Airways early next week if the Malaysian budget airline is to meet the May 19 service start it has advertised. That Max was the only one to fly on Friday, Alder said.

“The plan remains to start deliveries this month,” he said.

Lion Air said it hasn’t received any notice of a delivery delay from the US manufacturer. Norwegian Air Shuttle is also slated to receive its first 737 Max in late May.

Stock Impact

The newest 737’s progression to market had gone smoothly until this week, and Boeing shares fell Wednesday after the company said it would ground the fleet of more than 20 Max planes. Engine faults have also marred the debuts of Airbus SE’s A320neo and Bombardier Inc.’s C Series single-aisle jets.

Boeing’s potential quality flaw appears to be a “temporary manufacturing issue” at a second-tier supplier, said Richard Aboulafia, an aerospace analyst at Teal Group. The setback is probably less significant than the mechanical problems snarling deliveries of a Pratt & Whitney-powered Airbus jet or the engine fire in 2014 that grounded the C Series, he said.

The engine issue disclosed by Boeing this week “is nowhere near the technical uncertainties that the Airbus product has had,” said Howard Rubel, an aerospace analyst at Jefferies.

“They know right away what the problem is, as opposed to we have to figure it out,” Rubel said. “To me this is like a tempest in a teapot.”

The manufacturer is counting on a smooth market entry for the 737 Max, the latest version of a half-century-old aeroplane family that is the company’s largest source of profit. For now, much of the fledgling Max fleet remains grounded as Boeing, CFM and federal regulators develop a plan to clear the engines.