WASHINGTON (Reuters) - Boeing ( BA ) CEO Dave Calhoun will face tough questions from U.S. senators on Tuesday over the planemaker's safety culture as well claims from a new whistleblower employee.

Calhoun will appear at 2 p.m. ET (1800 GMT) before the Senate Permanent Subcommittee on Investigations, the first time he will face lawmakers' questions after a January mid-air emergency involving an Alaska Airlines 737 MAX 9 raised widespread alarm.

"This is a culture that continues to prioritize profits, push limits, and disregard its workers," the panel's chair, Senator Richard Blumenthal, said of Boeing ( BA ). "A culture that enables retaliation against those who do not submit to the bottom line. A culture that desperately needs to be repaired."

Blumenthal said a new whistleblower has come forward after a hearing with a previous whistleblower in April. Blumenthal said on Tuesday that Sam Mohawk, a current Boeing ( BA ) quality assurance investigator at its 737 factory in Renton, Washington, recently told the panel he had witnessed systemic disregard for documentation and accountability of nonconforming parts.

Boeing ( BA ) declined to comment on the new claims.

Calhoun will acknowledge shortcomings but seek to emphasize the company's efforts to improve.

"Much has been said about Boeing's ( BA ) culture. We've heard those concerns loud and clear. Our culture is far from perfect, but we are taking action and making progress," Calhoun will say in his written statement.

Blumenthal called the hearing a "moment of reckoning" for Boeing ( BA ).

"Boeing ( BA ) needs to stop thinking about the next earnings call and start thinking about the next generation," Blumenthal will say on Tuesday.

Since the Jan. 5 mid-air blowout of a door plug on a 737 MAX 9 jet, scrutiny of the planemaker by regulators and airlines has intensified. Boeing ( BA ) has shaken up management and Calhoun said in March that he will step down by year-end.

The National Transportation Safety Board said four key bolts were missing from the Alaska Airlines plane. The Justice Department has opened a criminal investigation into the incident.

Last week, Michael Whitaker, head of the Federal Aviation Administration, said the agency had been "too hands off" in its oversight of Boeing ( BA ) before the Jan. 5 accident. Another senator has also launched a probe into Boeing ( BA ).

On May 30, Boeing ( BA ) delivered a quality improvement plan to the FAA after Whitaker gave the company 90 days to develop a comprehensive effort to address "systemic quality-control issues." He has barred the company from expanding production of the MAX.

Last week, Boeing ( BA ) told the U.S. Justice Department it did not violate a deferred prosecution agreement after two fatal crashes of 737 MAX airplanes, a source familiar with the matter told Reuters. The DPA had shielded the company from a criminal charge arising from crashes in 2018 and 2019 that killed 346 people.