"It is miraculous, completely," said Ateny Wek Ateny, the South Sudanese presidential spokesperson. "There are only minor injuries. There was no single death."
The incident took place at the airport in Wau, in the nation's northwest.
Ateny said the pilot overshot the runway, dropping onto an unpaved ground.
The plane's right wing hit a car and a fire started on the right side of the plane, Ateny said. The pilot opened the door near the tail, which was not on fire.
"The crew managed to evacuate everyone," Ateny said.
Initially authorities were not able to find all the passengers because they fled the scene.
Wal Achieng, an official at South Supreme Airlines in Wau, said the plane carried 40 adults and three children. Twenty-five were taken to hospitals, Achieng said. Three remain hospitalized with minor injuries, Ateny said.
"The weather was not good," Achieng said, citing very cloudy conditions.
The plane was headed from the capital, Juba, to Wau. Juba is located in the southern region of the country.
Achieng said the fire initially led many people to think there would be no survivors.
South Sudan, which gained its independence from Sudan in 2011, has endured war political instability and famine.
It is a landlocked country in east-central Africa, bordering Sudan
, Ethiopia, Kenya, Uganda, Democratic Republic of the Congo and the Central African Republic
More than 12 million people live in South Sudan. It is populated by many ethnic groups, including the Dinka and Nuer, and the dominant faiths are Christian and animist.