Sudan's deputy defence minister and 13 other high-ranking military officers were killed when their plane crashed on take-off.
Sixteen people on the plane survived the crash, which was caused by bad weather, possibly a sand storm.
Six of the survivors were injured in the crash and were flown to Khartoum for treatment, military spokesman Lieutenant General Mohammed Bashir Osman said.
The crash took place in Adaril, in an oil-rich area 470 miles south of Khartoum that has been the scene of attacks on aircraft by rebels in the past.
State television said the deputy minister, Colonel Ibrahim Shamsul-Din, and the others had been touring a southern military area and were headed back to Khartoum when their plane skidded off the runway.
Shamsul-Din had backed the coup in which Sudanese President Omar el-Bashir's took power in 1989.
The military remains the main power broker in Sudan, not least because the country has been embroiled in civil war for 18 years.
The 15 dead included a general, seven lieutenant generals, three brigadiers, a colonel, a lieutenant colonel and a corporal.
The blow to Sudan's military hierarchy came amid sharpening tensions between the government and opposition leader Hassan Turabi, an Islamic ideologue who was el-Bashir's top ally until a falling out in 1999.
The President has been consolidating his position since the split.