WATCH LIVE: Boeing CEO testifies before Senate just hours after new whistleblower comes forward

Another Boeing whistleblower has stepped forward, a Senate office announced hours before the company’s CEO is set to testify Tuesday in Washington for the first time since the door plug of a 737 Max 9 blew off during an Alaska Airlines flight in January.

Sen. Richard Blumenthal’s (D-Conn.) office identified the whistleblower as Sam Mohawk, a quality assurance inspector for the planemaker in Renton, Wash. Mohawk alleges Boeing improperly tracked and stored faulty parts, and that those parts were likely installed on airplanes including the 737 Max, which is manufactured at the Renton facility.

"Mohawk has also alleged that he has been told by his supervisors to conceal evidence from the FAA, and that he is being retaliated against as result," according to a statement from the Senate Homeland Security's Permanent Subcommittee on Investigations.

“We received this document late Monday evening and are reviewing the claims. We continuously encourage employees to report all concerns as our priority is to ensure the safety of our airplanes and the flying public,” a Boeing spokesperson told The Hill.

Blumenthal chairs Homeland Security's investigations subcommittee, which is slated to grill Boeing CEO David Calhoun on the company’s “broken safety culture” at 2 p.m. EDT.

After the Alaska Airlines blowout in January, the outgoing CEO said Boeing was "accountable for what happened,” a sentiment he plans to echo in his opening remarks before the subcommittee.

“From the beginning, we took responsibility and cooperated transparently with the [National Transportation Safety Board (NTSB)] and the [Federal Aviation Administration (FAA)] in their respective investigations,” according to a copy of Calhoun’s prepared testimony shared with The Hill ahead of the hearing.

“In our factories and in our supply chain, we took immediate action to ensure the specific circumstances that led to this accident would not happen again,” Calhoun adds. “Importantly, we went beyond to look comprehensively at our quality and manufacturing systems.”

Federal aviation experts identified “gaps” in Boeing safety culture in a February FAA report that began before the Alaska Airlines blowout. The company presented its 11-page “Product Safety and Quality Plan” to the FAA last month detailing steps the company has taken to improve its safety culture and how it will measure its progress.

Multiple whistleblowers have come forward with allegations that the planemaker cut corners to increase profit and retaliated against employees who spoke up. Several testified before the subcommittee in April. 

During that hearing, Sam Salehpour, another Boeing quality engineer, alleged the company isolated, transferred and threatened him after he raised concerns that the fuselage of the company’s 787 Dreamliner were not properly fused together, which could cause the plane to break apart midflight.

“I want to make clear that I have raised these issues over three years. I was ignored. I was told not to create delays. I was told, frankly, to shut up,” Salehpour said.

After that hearing, a Boeing spokesperson told The Hill the company is “fully confident in the safety and durability of the 787 Dreamliner” and “extensive and rigorous testing of the fuselage and heavy maintenance checks of nearly 700 in-service airplanes to date have found zero evidence of airframe fatigue.”

Boeing has been working to get back in the good graces of lawmakers in the wake of the Alaska Airlines incident. A Boeing spokesperson previously told The Hill that the company's in-house lobbying team had reached out to all 535 members of Congress within a week of the accident.

Blumenthal expressed concern with what he described as “a culture that enables retaliation against those who do not submit to the bottom line” ahead of the hearing.

“This is a culture that continues to prioritize profits, push limits, and disregard its workers. A culture where those who speak up are silenced and sidelined while blame is pushed down to the factory floor,” Blumenthal said in a statement.