The U.K.’s competition watchdog has launched a formal investigation into Boeing’s ( NYSE: BA) planned acquisition of Spirit AeroSystems ( NYSE: SPR ), raising fresh regulatory obstacles for a deal aimed at improving the aerospace giant’s manufacturing quality and safety.

Boeing's impending acquisition of Spirit AeroSystems is under investigation by an antitrust regulatory agency in the U.K., which could result in delays for the deal. Boeing increases 737 Max production,