Senate lawmakers plan to grill Boeing’s chief executive at a hearing on Tuesday about the company’s safety practices in the wake of a harrowing flight in January during which a panel blew out of one of its planes.

In a report published hours ahead of the hearing, the Senate’s Permanent Subcommittee on Investigations accused Boeing of mismanaging parts and cutting quality inspections in recent years.

Boeing’s chief executive, Dave Calhoun, plans to express regret over the flight in January and admit to the subcommittee that the company’s culture is “far from perfect,” according to prepared remarks.

The hearing, scheduled for 2 p.m., will be Mr. Calhoun’s first appearance before Congress since the January flight, which involved a 737 Max 9 plane. Mr. Calhoun, who plans to step down at the end of the year, took over as chief executive in 2019 after two fatal crashes of a smaller version of the jet, the 737 Max 8. Those crashes, in which 346 people died, led to a 20-month global ban on the plane.

Senator Richard Blumenthal, a Democrat of Connecticut who is chairman of the subcommittee, said in a statement that Mr. Calhoun had assured lawmakers that he was the leader Boeing needed to turn the corner after the Max crashes in 2018 and 2019. Mr. Blumenthal said the company had appeared to be heading in the right direction until the January incident in which a “door plug,” which is used to cover an unused emergency exit, was ripped off during an Alaska Airlines flight at an elevation of about 16,000 feet near Portland, Ore. The incident exposed, Mr. Blumenthal said, a number of shortcuts the company had been taking all these years.

“This past January, the facade quite literally blew off the hollow shell that had been Boeing’s promises to the world,” Mr. Blumenthal said. “And once that chasm was exposed, we learned that there was virtually no bottom to the void that lay below.”

In its report, the subcommittee cited several whistle-blowers, including one who first publicly shared his concerns with The New York Times. The report also included claims from a another whistle-blower, a current Boeing employee, who accused the company of failing to track unapproved parts, and in some cases even allowing them to be used on the production line. The subcommittee also said that Boeing had engaged in a “yearslong effort” to cut quality inspections.

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

On May 30, Boeing outlined a required plan to the Federal Aviation Administration on how it would address safety and quality concerns that emerged after the door plug incident. Last week, the F.A.A. and European Union Aviation Safety Agency said they were investigating how titanium with falsified documentation made it onto Boeing and Airbus planes.

Boeing has said that it made several changes in the months since the panel blowout, including expanding training for new hires, ordering more tools and equipment, helping managers spend less time in meetings and more time on the factory floor, and increasing inspections both at Boeing and at a top supplier.

The company also said that it had re-emphasized its commitment to quality in more than 20 meetings at sites around the world in which work was paused and employees were encouraged to speak up about concerns and share ideas on how to improve quality. Tens of thousands of workers participated in those meetings, providing thousands of suggestions, the company said.

In his prepared remarks, Mr. Calhoun said that the company is taking steps to improve safety and quality. He apologized to the families of the victims of the Max crashes and said that the company regretted how the January incident affected the passengers and Alaska Airlines.

“Our airplanes have carried the equivalent of more than double the population of the planet,” Mr. Calhoun stated in his remarks. “Getting this right is critical for our company, for the customers who fly our planes every day and for our country.”