Travel in city Renton, state Washington

Boeing drew fresh criticism from a federal regulator on Thursday over disclosures about the continuing investigation into a harrowing January flight in which one of the company’s 737 Max planes lost a panel, exposing passengers to howling winds at an altitude of about 16,000 feet.

Boeing says it has achieved significant quality improvements in the production of the 737 Max since one of the planes lost a panel in a harrowing flight in January.

U.S. airlines had been looking forward to a strong summer. Holding them back: safety issues at Boeing and supply chain challenges at Airbus that are delaying deliveries of new planes.

The Federal Aviation Administration (FAA) announced it has halted production expansion of the Boeing 737 MAX following a six-week audit of Boeing and Spirit AeroSystems.According to the FAA, it "found multiple instances where the companies allegedly failed to comply with manufacturing quality control requirements" in the wake of a January 5 incident in which a door panel blew off an Alaska Airlines flight in mid-air."The FAA identified non-compliance issues in Boeing's manufacturing process control, parts handling and storage, and product control. The FAA is providing these details to the public as an update to the agency’s ongoing investigation," the agency said Monday."To hold Boeing accountable for its production quality issues, the FAA has halted production expansion of the Boeing 737 MAX, is exploring the use of a third party to conduct independent reviews of quality systems, and will continue its increased onsite presence at Boeing’s facility in Renton, Washington, and Spirit AeroSystems’ facility in Wichita, Kansas."

Four bolts used to secure the panel that ultimately blew off an Alaska Airlines plane during a flight last month were removed — and appear not to have been replaced — at Boeing’s factory in Renton, Wash., according to a preliminary report released Tuesday by the National Transportation Safety Board.