(NewsNation) — A whistleblower who says all Boeing 787 Dreamliner jets should be grounded testified that he was not listened to when he previously brought up safety concerns to the aerospace company.

Sam Salehpour, who sent documents to the Federal Aviation Administration amid its investigation into the quality of Boeing’s manufacturing, along with Ed Pierson, a former manager on the Boeing 737 program, spoke at a hearing for a subcommittee of the Senate Committee on Homeland Security and Governmental Affairs Wednesday.

“Boeing is at a moment of reckoning,” Sen. Richard Blumenthal, D-Connecticut, said in his opening remarks. “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 subcommittee, said.

Salehpour accuses Boeing of taking shortcuts to speed up the production of its planes. Specifically, he’s alleged that the way 787 Dreamliner fuselages are made could cause them to break apart many years into use.

In an interview with NBC News, he said the “entire fleet 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 the airplanes’ 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.”

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

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 737 Max as it flew above Oregon in January.

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

Another hearing on Wednesday in front of the Senate Commerce Committee focused on the agreement that many say allows Boeing to regulate itself, signing off on inspections and tests on behalf of the Federal Aviation Administration.

A review of that provision found “a disconnect between Boeing’s senior management and other members of the organization on safety culture. “

Members of an expert panel testified about a report they wrote, which found flaws in Boeing’s safety culture. That panel included Dr. Javier de Luis, a lecturer in the Massachusetts Institute of Technology’s Aeronautics and Astronautics department, whose sister was killed when a Boeing 737 Max 8 crashed in Ethiopia in 2019.

The panel said in their report, issued in February, that despite improvements made after the crash in Ethiopia and another crash off the coast of Indonesia the year before, Boeing’s approach to safety is still not up to par. There were 346 total people who died in the two crashes.

Employees who raise concerns, the report said, could be subject to pressure and retaliation.

“For me serving on this panel has been an opportunity to help prevent anyone else from going through what I and my family have sadly experienced these past five years,” de Luis said.

He described a “disconnect” between what is being said by Boeing management, and what is being seen and experienced by employees across the company.

“They hear safety is our number one priority,” de Luis said. “But what they see is that that’s only true as long as your production milestones are met. And at that point, it’s ‘push it out the door as fast as you can.'”

When talking to Boeing workers, de Luis said he heard “there was a very real fear of payback and retribution if you held your ground.”

The Associated Press contributed to this report.

This story is developing. Refresh for updates.