The operator of the doomed Amazon Prime Air cargo plane that crashed in Miami, killing five people, has been the subject of numerous safety complaints by former employees, including some who claim they were fired for blowing the whistle.

Numerous senior staff members have filed complaints against 21 Air, a North Carolina-based operator controlled by Houston Astros owner Jim Crane through an LLC — with some saying they long feared a tragedy like Sunday’s crash.

“It’s something a lot of us ex-21 Air pilots have been anticipating for a while,” retired 21 Air pilot Tony Bless told CBS News, citing perennial concerns like”maintenance safety issues, the pressure out of the chief pilot’s office, and the quality of pilots they would hire.”

Whistleblowers have alleged everything from failing to properly document safety concerns to hiring pilots who couldn’t speak English to pressuring pilots to complete their routes too quickly to comply with rest requirements.

“Unfortunately, 21 Air has a long-established history of safety problems,” Karl Seuring, a veteran pilot who filed a legal complaint against the company, told CBS News.

Seuring claimed that when he raised safety concerns he was told by a 21 Air manager, “It’s not going to change.”

He alleged he was fired over the complaint, however his claim was initially rejected by the Occupational Safety and Health Administration (OSHA). His appeal is still pending before a Department of Labor tribunal, in which a federal judge will hear the case.

A former fighter pilot reviewing safety policy for 21 Air wrote in his resignation letter that company executives were merely “paying lip service” to safety protocols “then doing exactly nothing” when presented with concerns.

Bruce Joseph, a former chief pilot for 21 Air, testified in his own Labor Department tribunal that he had “personal knowledge of people being discouraged” from recording safety concerns.

He alleged the firm’s former director of safety once told him “don’t put anything” in the company’s safety management software before speaking with the company’s then-CEO, Mike Mendez, telling a judge in 2024 if he had, it would have incurred “the wrath of Mike.”

In his testimony, Mendez accused Joseph of trying to “make up” damaging claims about the company and claimed he “was fired from 21 Air and left under very bad circumstances.”

He also flatly denied any retaliation claims, and insisted he followed safety protocols by the book.

“My responsibility is to make sure we run a safe airline, not to hurt people and not to hide anything,” he testified.

Seuring raised an incident in his tribunal testimony in which he was seated in the jump seat of a 21 Air Boeing 767 in 2022 when a mechanical issue caused the plane to rapidly accelerate after takeoff — bringing it to speeds that could cause wing flap damage and leaving him “concerned for my own safety,” the outlet writes.

He pointed to a ‘breakdown of communication” between the captain and the first officer after the incident.

“We had no debrief. No discussion. Assume it didn’t happen,” Seuring said.

Michael Anello, Seuring’s lawyer, said at the tribunal that another 21 Air pilot, Johnny Salmonson, “was being pressured to fly in periods of time that were too short to comply with the proper amounts of rest, and that implicated safety,” he said.

“The layovers were too short. The management was pushing the pilots, and the result was he was retaliated against.”

Seuring said pilots were on their own when it came to ensuring they were adequately rested between flights.

“None of these airplanes had good crew rest on board,” he told the outlet.

“My vice president of the union actually bought sleeping bags for airplanes to give the pilots a reasonable way to get some crew rest on long nighttime flights.”

Bless, the retired pilot who said he “anticipated” an accident, said the company routinely deferred maintenance, and that problems would frequently arise with its aging fleet of converted passenger planes.

He claimed his 21 Air plane’s radar once stopped working in 2022 when he was flying from Bermuda to New Jersey, moments after the crew navigated the worst turbulence he experienced in his four-decade career.

“I let the company know in no uncertain terms that I would not fly that plane again until they put a new radar in,” he said.

“We’ve had fuel leak issues. We’ve had radar problems and circuit breakers, smoke in the cockpit,” Seuring told CBS News. “Pilots were coached on how the write-ups should be done.”

The Boeing 767 that crashed in Miami was approximately 33 years old — many airlines begin phasing out aircraft once they reach 20-25 years in service, according to a recent CNN report.

The five people killed in the crash were part of a cleaning crew in a van struck by the plane, Miami-Dade County Sheriff Rosie Cordero-Stutz said.

Captain Joseph Carroll, 55, and First Officer Jaime Felipe Silva Molina, 37, have been identified as the pilots, who were both survived but were hospitalized.

Reps for 21 Air did not immediately respond to The Post’s request for comment.