Russia is to deliver 18 used Su-30K fighter aircraft to an unspecified African country, which is presumed to be Angola. Twelve aircraft will be delivered initially, followed by another batch of six.
The Su-30K aircraft in question formerly belonged to the Air Force of India and were part of the initial aircraft supplied as part of the Su-30MKI deal agreed to in 1996 between Russia and India.
At the time of signing, the Su-30MKI did not exist, but was a paper design that would have to be developed. Basically, the Su-30MKI is a modified version of the Russian Su-30MK, but with certain Russian components such as the avionics replaced by western or Indian parts.
It also incorporated features found in the more advanced Su-35 / Su-37. Unlike the basic Su-30MK, the Su-30MKI features canards as in the Su-35 and thrust-vectoring engines as in the Su-37.
According to the 1996 deal, 40 Su-30 aircraft would be build in Russia and delivered to India, which was later increased to 50 when India bought another 10 aircraft in 1998.
In 2000, India and Russia agreed to licensed production of 140 aircraft in India through various stages. This was later increased by a deal for 40 aircraft in 2007 and another 42 aircraft in 2010.
The 50 Su-30 from Russia were supplied in five batches starting in 1997, with each batch incorporating more and more features of the final Su-30MKI standard. The first two batches of 8 and 10 are the aircraft that will now be supplied to Angola after they were returned to Russia in 2007.
They were only capable in the air-to-air role and can be distinguished from the later aircraft by their lack of canards. They were primarily used for training and getting Indian pilots familiar with the Su-30 platform.
During their stay in India, they reportedly encountered a number of technical difficulties such as issues relating to the engines and were in relative bad condition when they were returned.