The Amazon Prime Air Boeing 767 cargo plane that crashed off a Miami runway on Sunday, killing five people, was operated by a North Carolina company that has been accused by past employees of violating safety regulations, legal documents reveal.The cargo airline hired by Amazon, 21 Air, is controlled by Houston Astros owner Jim Crane through an LLC. The company has faced a string of safety complaints from senior staff who claim they were fired for raising concerns, CBS News has learned from records and interviews."Unfortunately, 21 Air has a long established history of safety problems," said Karl Seuring, a pilot with more than 30 years of experience who filed a legal complaint alleging that when he raised safety concerns he was told by a 21 Air manager, "It's not going to change."The Occupational Safety and Health Administration (OSHA) rejected Seuring's complaint over his alleged retaliatory firing by 21 Air. His appeal led to a 2023 Department of Labor tribunal — a hearing in front of a federal judge — where the case is still pending.Seuring and other former 21 Air pilots claimed managers suppressed safety reports, pushed crew to fly without proper rest, staffed pilots who could not communicate safely in English, and put faulty planes in the sky, documents show.Executives were accused of "paying lip service" to safety procedures "then doing exactly nothing," according to a resignation letter written by a former fighter pilot reviewing safety policy for the company and sent to 21 Air owner Crane in 2021.Former 21 Air chief pilot Bruce Joseph testified in the Labor Department tribunal that he had "personal knowledge of people being discouraged" from logging safety concerns in the company system "on numerous occasions."