Federal officials have briefed a congressional committee on their investigations into a jetliner that lost a panel of its fuselage in midflight this month and revealed that airlines have inspected 40 identical Boeing planes.

The Federal Aviation Administration said it will review information from those inspections of Boeing 737 Max 9 jets while it develops a maintenance process before letting the planes carry passengers again.

Jennifer Homendy, chair of the National Transportation Safety Board, and FAA Administrator Mike Whitaker spent two hours briefing members of the Senate Commerce Committee in Washington on Wednesday as questions continue to swirl around how the panel of an Alaska Airlines jetliner blew off while traveling 16,000 feet above Oregon. The officialsindicated that their separate investigations of Boeing and the accident are in the early stages.

“Nothing was said about penalties or enforcement, but when there is an end result, I have no doubt but that there will be consequences,” said Sen. Jerry Moran, a Kansas Republican, in an interview after the closed-door session.

Moran said Whitaker indicated that the FAA is focusing “on the challenges that Boeing has faced over a longer period of time, of which this incident, this potential disaster, was only one component.”

During the briefing, “there was also interest in trying to make sure that the FAA is doing its job in its oversight,” Moran said.

The FAA and NTSB declined to comment on the briefing.

Separately, Homendy said her agency will look into how exactly the panel was produced by Spirit AeroSystems and installed on the Alaska Airlines plane. She told reporters after the briefing that the panel was manufactured in Malaysia by Boeing’s leading supplier.

That development puts more attention on Boeing’s global supply chain. Over a period of many years, the company outsourced much if its manufacturing.

A spokesman for Spirit AeroSystems confirmed that the plug was made in Malaysia and said the company is committed to cooperating with the NTSB.

Meanwhile, Boeing’s CEO David Calhoun spent the day visiting the Wichita, Kansas, factory of Spirit AeroSystems. He vowed that the two companies will work together to “get better.”

Calhoun and Spirit CEO Patrick Shanahan — a former Boeing executive and acting U.S. defense secretary whose nomination by President Donald Trump to lead the Pentagon failed — met with about 200 Spirit employees in what the companies termed a town hall.

“We’re going to get better” because engineers and mechanics at Boeing and Spirit “are going to learn from it, and then we’re going to apply it to literally everything else we do together,” Calhoun said.

Shanahan told the workers that by working with the NTSB, FAA, the airlines and Boeing, “we will restore confidence.”

The meeting of CEOs occurred as both companies face scrutiny over the quality of their work.

An Alaska Airlines Max 9 was forced to make an emergency landing on Jan. 5 after a panel called a door plug blew out of the side of the plane shortly after takeoff from Portland, Oregon.

The NTSB is investigating the accident, while the FAA investigates whether Boeing and its suppliers followed quality-control procedures.

Alaska and United Airlines, the only other U.S. airline that flies the Max 9, reported finding loose hardware in door plugs of other planes they inspected after the accident. Both airlines havecanceled hundreds of flights while their Max 9s are grounded.

Boeing shares gained 1% on Wednesday but havedropped 18% since the accident, making the Arlington, Virginia, company the worst performer in the Dow Jones Industrial Average in that span.