The infamous Antonov (An -26 and An-24) cargo planes/crude retrofitted bombers
The Antonov-26 is the Antonov currently deployed by Khartoum’s SAF (here shown in Nyala, Darfur; photograph Human Rights Watch)
The Antonov-24 was its predecessor and used through at least 2007
The Antonov remains by far the most heavily used aircraft in Khartoum’s aerial assaults on civilian and humanitarian targets in Darfur, Blue Nile, and South Kordofan. It typically flies slowly at approximately 5,000 meters–out of the range of anti-aircraft guns. At this very considerable height, crude barrel bombs are simply pushed out the cargo bay, without aid of a siting mechanism or other targeting apparatus. Bombs delivered in such fashion are highly inaccurate, and for true military purposes they are useless. But as weapons of civilian terror, they are exquisitely suited; even their inaccuracy brings fear. They have almost completely destroyed the agricultural economies of the Nuba Mountains and Blue Nile, creating terrible living conditions for some 1.5 million people.
A detailed account of the aircraft and ordnance used by Khartoum’s air force in its campaigns in Darfur, South Kordofan (Nuba Mountains), and Blue Nile State—and not infrequently South Sudan—is provided in the 7 February 2014 report by the UN Panel of Experts: http://www.un.org/ga/search/