Two ex-pilots of the Mexican charter company whose aircraft crashed in Cuba killing 110 people on board claimed the carrier had received previous safety complaints.
One of the pilots described how an aircraft leased from Damojh airlines had dropped off radar completely some eight years ago. Another alleged poor maintenance.
Mexican authorities say they will carry out a safety audit of the company.
Three women survived Friday’s crash near Havana airport – Cuba’s deadliest air disaster in more than 30 years.
The Boeing 737 went down shortly after taking off on a domestic flight to Holguin carrying 105 passengers and six crew members.
Cuban authorities have started an investigation into the crash, as rescuers continue to comb through the wreckage site some 12 miles south of the Cuban capital.
One of two “black boxes” that hold key flight data and information about what happened to the aircraft has been recovered and is said to be in good condition.
Allegations of previous safety complaints have emerged against the Mexican-based Damojh company, which leased both the Boeing 737 and its crew to Cuba’s state Cubana airline.
The head of Guyana’s civil aviation body, Captain Egbert Field, told the Associated Press news agency the same aircraft – which was nearly 40 years old – had been barred from using Guyanese airspace last year after authorities found its crew were overloading luggage on flights in Cuba.
A retired pilot for Cubana wrote on Facebook that another aircraft leased by the airline from the same company had briefly dropped off radar for unspecified reasons while over the central Cuban city of Santa Clara in 2010 or 2011, the BBC reported.
The captain and co-pilot of that flight were later suspended for “problems and serious lack of technical knowledge,” said Ovidio Martinez Lopez, who worked for Cubana for more than 40 years.
He said “many flight attendants and flight safety personnel” had refused to fly on certain Cubana aircraft over the years.
Another pilot who used to work for Damojh told Mexican newspaper Milenio he had complained about a lack of adequate aircraft maintenance.
“I experienced several incidents at this company, like engine failure or the electrical system went when we took off from Mexico on one occasion,” Marco Aurelio Hernandez was quoted as saying.
A Damojh employee in Mexico City declined to comment to the Associated Press, saying the company would be communicating only through written statements.
Mexican authorities said Damojh had permits needed to lease its aircraft and had passed a November 2017 verification of its maintenance programme.
The government in Mexico released a statement saying its national civil aviation authority will carry out a new “operational audit” of Damojh to see if its “current operating conditions continue meeting regulations, as well as collecting information to help the investigation”.