(NewsNation) — A whistleblower who says all Boeing 787 Dreamliner jets should be grounded by the aerospace company for safety reasons is testifying in front of lawmakers at Congressional hearings Wednesday.

Sam Salehpour, who sent documents to the Federal Aviation Administration amid its investigation into the quality and safety of Boeing’s manufacturing, along with Ed Pierson, a former manager on the Boeing 737 program, are speaking at the Senate committee hearings. Two other aviation technical experts are on the witness list for the proceedings as well.

“Boeing is at a moment of reckoning,” Sen. Richard Blumenthal, D-Connecticut, said in his opening remarks for one of the hearings. “It’s a moment many years in the making.”

Wednesday’s hearings are the first of several lawmakers intend to have so they can get to the bottom of “Boeing’s broken safety culture,” Blumenthal, who chairs the Senate Committee on Homeland Security and Governmental Affairs’s permanent Subcommittee on Investigations, said.

Salehpour accuses Boeing of taking shortcuts to speed up the production of its planes. In an interview with NBC News, he said the “entire fleed worldwide, as far as (he’s) concerned right now, needs attention.”

At the hearing, Salehpour reiterated his claims about these manufacturing shortcuts, and said they significantly reduce airplane safety and their life cycle.

Over three years, Salehpour said, he raised concerns about issues he saw, but was ignored.

“I was told not to create delays,” Salehpour testified. “I was told, frankly, to shut up.”

Eventually, Salehpour said, he was reassigned from the 787 program to the 777 program after speaking out.

Asked by NBC if he would put his family on a 787 jet right now, Salehpour said, “I would not.”

These assertions made by Salehour come amid several incidents that caused concern about Boeing planes, including when a plug covering an unused exit door blew off a Boeing 737 Max as it flew above Oregon in January.

Boeing said in a statement that it is “fully confident in the 787 Dreamliner” and that the issues do not present any safety concerns.

A Boeing spokesperson told NewsNation that the company continues to cooperate with both lawmakers and investigators.

The Associated Press contributed to this report.

This story is developing. Refresh for updates.