Boeing CEO testifies in Senate, new whistleblower claims they hid questionable parts from regulators

WASHINGTON -- Boeing CEO David Calhoun apologized to the families of victims of previous plane crashes involving the company's planes, including the 737 Max, before being grilled by senators Tuesday during a hearing on Capitol Hill.

Sen. Richard Blumenthal invited the families to the highly anticipated hearing, and many came holding posters of loved ones killed, including in the crash of Lion Air Flight 610 off Indonesia in 2018 and Ethiopian Airlines Flight 302 near Addis Ababa in 2019.

Before Calhoun began his opening statement, he turned and faced the families.

"I apologize for the grief we have caused," he said. "We are focused on safety."

Blumenthal, the Democratic chairman of the Senate Homeland Security and Governmental Affairs subcommittee, thanked the families for joining the hearing.

"The issues before us today have real human consequences [and] real Life and death results," the senator said.

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In his opening statement, Blumenthal hearing pressed Calhoun, who is resigning at the end of the year, on whether the executive has made progress in turning the company around.

The senator mentioned the incident in January when a door plug blew out of an Alaska Airlines Boeing 737 Max 9 shortly after takeoff. He said that the "faade quite literally blew off the hollow shell that had been Boeing's promises to the world."

"Mr. Calhoun, you were brought in turn this company around," Blumenthal said. "But instead of asking what has caused Boeing's safety culture to erode, you and your colleagues in the C-suite have deflected blame, looked the other way, and catered to your shareholders instead."

Calhoun repeatedly reassured the senators that he was turning the company around and focusing on preventing any safety issues.

He said that more inspectors have been sent to Spirit AeroSystems, the company that was responsible for assembling Boeing's 737 Max fuselage, and other companies that help build their craft.

"We have revamped our engineering practices at large," he said.

Blumenthal and other senators questioned the CEO over its treatment of whistleblowers over the years.

Several former employees have testified that the company has retaliated against people speaking out against the company or raising concerns about current practices.

When Blumenthal asked Calhoun his thoughts on the former Boeing employee John Barnett, who took his own life on March 9 after he raised his voice over quality concerns, the CEO said he was "heartbroken."

Barnett's family was also in attendance during the hearing.

Calhoun said that the company does take employee concerns seriously and encourages them to talk with supervisors.

"We have a process it works," Calhoun said.

"I beg to differ," Blumenthal said citing Barnett's claims.

Blumenthal expressed doubt about Boeing's promises to change its culture contending the company passes down the blame downwards and doesn't take action on managers.

"I think there has to be a change in more than one single manager," he said.

"I do believe in accountability," Calhoun said.

The hearing came after not long after Blumenthal said he received new information about Boeing's questionable practices.

His office said on Tuesday that a current Boeing employee has come forward as a whistleblower identified the employee as Sam Mohawk, a quality assurance inspector for Boeing in Renton, Washington.

Mohawk alleges that Boeing is cutting corners by losing track of parts that have been labeled as non-conforming or not up to design standards, according to Blumenthal. Sometimes these parts get a second chance because they can be fixed or were mislabeled, but often they should be discarded. Still, the parts sometimes end up in newly built airplanes, Mohawk said, according to the senator.

"He said that he has been told by his supervisors to conceal this evidence from the FAA, and that he is being retaliated against as well," Blumenthal said in a statement.

A Boeing spokesperson said the company had received on Monday evening the documents supplied to Blumenthal by the whistleblower. The company is reviewing the claims now, the spokesperson said on Tuesday.

"We continuously encourage employees to report all concerns as our priority is to ensure the safety of our airplanes and the flying public," the spokesperson said.

The latest whistleblower stepped forward as Calhoun prepared to sit for a Senate hearing on his company's "broken safety culture." Previous whistleblowers have accused the Arlington, Virginia-headquartered company of cutting corners on safety practices as it builds aircraft.

Calhoun in January said Boeing was "accountable for what happened" during the Alaska flight.

"Whatever the specific cause of the accident might turn out to be, an event like this must simply not happen on an airplane that leaves one of our factories," he said at the time. "We simply must be better. Our customers deserve better."

ABC News' Clara McMichael contributed to this report.