The accident occurred Friday in Bwabwata game park, said Tobias Günzel, acting director of Namibia's Civil Aviation Department. The location is a remote region near the Angolan border,
Günzel said the plane started losing altitude at 38,000 feet and went down swiftly, CNN reported.
"We could see it on our radar, and we could see it was descending very quickly, at a rate of about 100 feet per second," Günzel said. "We lost it from our screens at 3,000 feet above sea level."
The airline has not confirmed the crash, but the company released a statement earlier confirming 28 passengers and six crew members were on Flight TM 470 and that it was "missing."
The flight was en route from Maputo, Mozambique, to Angola. Namibia's aviation authorities have dispatched a police helicopter to the area, Günzel said.
"We now have to wait and see if the black box can be recovered," Günzel said.