Family members of four passengers who died with singer Jenni Rivera when her plane crashed in northern Mexico last year sued her corporation and the current and former owners of the aging Learjet they called a "bucket of bolts" on Thursday.
The plaintiffs alleged in their Los Angeles Superior Court lawsuit that the 43-year-old aircraft was unsafe and being flown by two unqualified pilots when it nosedived from 28,000 feet (8,500 metres) into mountainous terrain.
"We are trying to unravel the mystery of how this came to be. Who selected this plane, what condition was this plane in and how did these pilots get behind the stick of this aircraft?" plaintiffs' attorney Paul Kiesel said.
"We want to provide answers for my clients and for the community mourning these brilliant lives," he said.
Rivera and her fellow passengers were flying from Monterrey, Mexico, to an airport in the Mexico City suburb of Toluca in the early morning hours of Dec. 9 when the Learjet 25 went down.
The 43-year-old California-born singer, best known for her work in the Mexican folk Nortena and Banda genres, had been headed to Mexico City for an appearance on the TV singing competition "The Voice Mexico."
Killed with her were publicist Arturo Rivera (no relation), make-up artist Jacobo Yebale, attorney Mario Macias Pacheco and hair stylist Jorge Armando "Gigi" Sanchez Vasquez, along with the pilot and co-pilot.
Since the plane was registered in the United States, members of the National Transportation Safety Board are taking part in the investigation, which was expected to last a year.
Representatives for Jenni Rivera Enterprises and for Starwood Management, the charter company that owned the aircraft at the time of the crash, could not be reached by Reuters for comment on the lawsuit.
A Starwood executive previously told the Los Angeles Times that the plane was properly maintained and suggested that the 78-year-old pilot, Miguel Perez Soto, might have suffered a heart attack or become incapacitated in some way.
According to the 22-page lawsuit, the multi-engine plane involved in the crash had been built in 1969 and "was such an old airplane that it was referred to as a 'bucket of bolts.'"
The lawsuit says it struck a runway marker at an airport in Texas in 2005, which left the plane with structural damage.
The plaintiffs also say in the court papers that Soto was not licensed to fly the Learjet above 18,000 feet (5,500 metres) or with paying passengers. The co-pilot, 20-year-old Alejandro Jose Torres, also lacked certification for flying the plane under those conditions, according to the lawsuit.