Chemical analyses, CFR engine knock tests, and a full scale turbocharged aircraft engine detonation test were conducted to compare the detonation characteristics of Soviet Grade GOST 1012-72 fuel and a commercially available Grade 100 Low Lead Aviation Gasoline. Chemical analysis indicated significant differences in the composition of the two fuels, particularly with respect to aromatic and tetraethyl lead contents. CFR engine knock test data indicated that the GOST 1012-72 fuel clearly was lower in knock value than the 100 Low Lead fuel, and full scale engine detonation testing supported these results. Modified detonation-imposed operating limitations were developed for the full scale aircraft engine model tested. No conclusions have been made with respect to long-term effects of GOST 1012-72 fuel usage on engine condition and performance.