 At the 1996 Seoul Air Show , Russia submitted the Su @-@ 35 ( Su @-@ 27M ) and Su @-@ 37 for South Korea 's F @-@ X procurement programme , a 40 @-@ aircraft requirement to replace the Republic of Korea Air Force 's F @-@ 4D / Es , RF @-@ 4Cs , and F @-@ 5E / Fs . The Su @-@ 35 competed against the Dassault Rafale , Eurofighter Typhoon , and F @-@ 15K Slam Eagle . The proposed Su @-@ 35 featured a phased grid radar and AL @-@ 31FP vectoring @-@ thrust engines ; final assembly would have taken place in South Korea , the offer included a full technology transfer . The US $ 5 billion contract may have been partially financed through a debt @-@ reduction deal on money Russia owed to South Korea . The Su @-@ 35 was reportedly the cheapest aircraft to purchase and maintain , however it was eliminated early in the bidding process , along with the Typhoon . The F @-@ 15K , viewed as the competition 's front @-@ runner due to South Korea 's ties with the United States , was chosen in 2002 . Reports have claimed that , had South Korea not chosen the F @-@ 15K , the United States would have refused to integrate American weapons on the selected aircraft . 
