Boeing Sanctioned by NTSB Over Disclosures on 737 Max Investigation

Boeing drew fresh criticism from a federal regulator on Thursday over disclosures about the continuing investigation into a harrowing January flight during 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.

Addressing reporters at a company factory in Renton, Wash., Elizabeth Lund, a Boeing executive, provided new details on Tuesday about how the plane involved in the incident left the plant apparently without four critical bolts that secured the panel, known as a door plug, in place.

Boeing said the information was not for release until Thursday morning, under a common kind of agreement that allowed the attending reporters time to process the detailed briefing.

But the National Transportation Safety Board became aware of the remarks at the briefing and rebuked the company hours before articles on the remarks were published. It said that Boeing improperly shared investigative information and speculated about the cause of the incident, adding that the company had “blatantly violated” the agency’s rules surrounding active investigations. The agency said it would provide details about that violation to the Justice Department, which is investigating the January flight.

“As a party to many N.T.S.B. investigations over the past decades, few entities know the rules better than Boeing,” the agency said in a statement.

The N.T.S.B. also said that it would revoke Boeing’s access to investigative information and that the company would not be allowed to ask questions of other participants at a hearing in August, for which it plans to subpoena Boeing witnesses. The agency said it confirmed the company’s violation after obtaining a transcript of the press briefing from Boeing. The agency’s rebuke of the company was earlier reported by The Air Current, an aviation publication.

In a statement, Boeing apologized for speaking out of turn.

“We deeply regret that some of our comments, intended to make clear our responsibility in the accident and explain the actions we are taking, overstepped the N.T.S.B.’s role as the source of investigative information,” the company said. “We apologize to the N.T.S.B. and stand ready to answer any questions as the agency continues its investigation.”

In a letter addressed to Boeing’s chief executive, Dave Calhoun, an N.T.S.B. official noted that the agency had already warned Boeing in March about adhering to its rules. The official also…