"The plane took off from Bukavu late morning. It crashed shortly afterwards in the national park of Kahuzi-Biega.
There were five people on board. Two were injured, one passenger and the pilot," said Georges Matutu, director of Bukavu airport.
"The plane caught fire after the accident. We do not yet know what happened."
The Antonov 2, a small cargo plane, was headed for the Nzonvu airport in Shabunda territory in South Kivu in the east of the country, with three passengers and two crew on board.
Plane crashes are common in DRC.
According to figures complied by AFP at least 34 people have been killed in accidents involving private DRC airlines.
Earlier this month, three foreigners and a DRC pilot died when the private plane they were travelling on crashed in DRC, apparently after hitting an overhead cable.