Brazil's Center for Research and Prevention of Aeronautical Accidents (CENIPA), in the interests of improving aviation safety, had said it would join a Russian-led investigation if it were invited and the probe held under international rules. U.S. aviation safety consultant and former investigator John Cox said an internal Russian investigation would always be questioned without the participation of Brazil, the country where the plane was manufactured. "I think it hurts the transparency of the Russian investigation." In air crash investigations, experts work to improve aviation safety without assigning blame, but probes are often tainted by political interests. Jeff Guzzetti, a former U.S. air crash investigator, said Russia should accept assistance from Brazil, even if CENIPA can only participate remotely.

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Persons: Wagner, Yevgeny Prigozhin, Anton Vaganov, Prigozhin, Vladimir Putin's, Marcelo Moreno, John Cox, Cox, CENIPA, Jeff Guzzetti, Allison Lampert, Gabriel Araujo, Valerie Insinna, Denny Thomas, Grant McCool Organizations: Police, REUTERS, SAO PAULO, Embraer, EMBR3, Reuters, Wagner Group, Brazil's Center for Research, Aeronautical, United Nations International Civil Aviation Organization, Interstate Aviation Committee, Accident Investigation, U.S ., Convention, International Civil Aviation, Thomson Locations: Tver, Russia, MONTREAL, SA, Moscow, Russian, Ukraine, Montreal, St Petersburg, Brazil, U.S, Sao Paulo, Washington