Boeing Co. has halted deliveries of its 787 Dreamliner just two months after restarting them as the company works to get regulatory approval for its plan to resolve previously disclosed quality issues.

The planemaker is providing the U.S. Federal Aviation Administration with added analysis and documentation of proposed fixes for undelivered jets, according to a company statement Friday. The latest setback follows a five-month delivery hiatus that ended in March, caused by potential manufacturing flaws in the carbon-fiber shell of Boeing’s most advanced aircraft.

“Boeing still needs to show that its proposed inspection method would meet FAA’s federal safety regulations,” the regulator said by email. Because the FAA hadn’t approved Boeing’s proposed system of compliance, the company chose to suspend shipments of the plane, the agency said.

The new interruption to a key source of cash deals Boeing yet another blow tied to manufacturing lapses in its marquee jets. Shortly after the company resumed Dreamliner shipments this year, it ordered 737 Max planes to stop flying because of a potential electrical fault. While Max deliveries began again this month, the glitch marred the model’s return from a 20-month worldwide grounding after two deadly crashes.

Boeing declined 1.5% to $247.03 at 11:24 a.m. in New York, the biggest drop on the Dow Jones Industrial Average. Boeing had advanced 17% this year through Thursday as global Covid-19 vaccination rates spurred optimism for an aviation recovery.

Limited Impact

Boeing said there would be no impact on planes that are in service.

American Airlines Group Inc. expects that any delivery delay will be minimal and that it plans no changes for its fleet of 787s, a spokesman said. The airline has 46 Dreamliners in service, according to Cirium Fleets Analyzer.

The issues that led to the latest halt aren’t new and don’t affect flight safety, a person familiar with the matter said.

Last year, Boeing discovered tiny dimples in the inner lining where the 787’s carbon-fiber fuselage barrels are fused to form the jet’s frame.

Boeing said in late April that it had about 100 Dreamliners in inventory and expected to clear most of those by year-end. At the time, Chief Executive Officer Dave Calhoun said he expected to deliver about a dozen of the twin-aisle aircraft monthly. That schedule could be at risk the longer the talks with the FAA drag on, crimping Boeing’s ability to meet its cash-flow goals.

The Chicago-based company has struggled to get past a series of missteps that have led to heightened regulatory scrutiny. This week, Boeing agreed to pay at least $17 million to settle U.S. enforcement cases about the installation of unapproved equipment on hundreds of single-aisle 737 jets.