A South African National Defense Force spokesman said rescuers were searching for survivors Thursday, but did not comment on the plane's mission or the number of people aboard, CNN reported.
Spokesman Siphiwe Dlamini said initial reports of Mandela's medical team being aboard the aircraft were false, Eyewitness News reported.
The aircraft took off Wednesday from Waterkloof Air Force Base in Pretoria to an airport in Mthatha, a town about 20 miles from the Qunu village where the Nobel Peace Prize laureate lives, the defense spokesman said.
"The aircraft went down on the Drakensberg Mountains range in an area called Giant's Castle Peak," Dlamini said.
He said wreckage of the Dakota DC3 C47 plane was strewn over a large area.
Mandela, 94, has not been seen in public since South Africa hosted the 2010 World Cup. The former president, imprisoned for 27 years for fighting against black oppression in South Africa, has been receiving 24-hour care after abdominal surgery this year and an acute respiratory infection in 2011.