Question: The Advanced Tactical Fighter (ATF) was a demonstration and validation program undertaken by the United States Air Force, including the Soviet Sukhoi Su-27, a twin-engine supermaneuverable fighter aircraft designed by Sukhoi, it was designed to complement which aircraft?
Sentence (from "General Electric YF120"): The General Electric YF120 was a variable cycle turbofan engine designed by GE Aircraft Engines in the late 1980s/early 1990s for the United States Air Force's Advanced Tactical Fighter (ATF) project (which resulted in the F-22 Raptor).
Relevant evidence: No