▁gain ▁further ▁clar ity ▁as ▁the ▁debate ▁about ▁the ▁Ans bach ▁results , ▁the ▁Army ▁commission ed ▁B DM ▁International , ▁now ▁part ▁of ▁V inn ell , ▁to ▁prepare ▁a ▁follow - up ▁theoretical ▁study . ▁The ▁T act ical ▁Hel ic opter ▁Emp loyment ▁Study , ▁or ▁TH ES , ▁was ▁largely ▁a ▁literature ▁search , ▁an ▁attempt ▁to ▁find ▁and ▁collect ▁all ▁useful ▁information ▁on ▁the ▁topic ▁of ▁attack ▁hel ic op ters ▁to ▁date . ▁Pub lished ▁in ▁November ▁ 1 9 7 3 , ▁TH ES ▁made ▁three ▁broad ▁conclus ions : ▁▁ ▁previous ▁experiments ▁and ▁operations ▁generally ▁supported ▁each ▁other ' s ▁results ▁ ▁do ctr ines ▁developed ▁during ▁these ▁events ▁appeared ▁to ▁be ▁correct ▁and ▁well ▁accepted ▁ ▁the ▁attack ▁hel ic opter ▁could ▁be ▁used ▁as ▁a ▁primary ▁anti - arm or ▁weapon ▁ ▁TH ES ▁also ▁considered ▁the ▁issue ▁of ▁weather , ▁and ▁using ▁data ▁collected ▁from ▁six teen ▁sites ▁over ▁a ▁ten - year ▁span , ▁they ▁concluded ▁that ▁the ▁Cob ra ▁could ▁fly ▁ 9 1 % ▁of ▁the ▁time , ▁even ▁during ▁the ▁worst ▁weather ▁in ▁November ▁and ▁December . ▁ ▁Out comes ▁In ▁ 1 9 7 6 , ▁as ▁a ▁direct ▁result ▁of ▁the ▁tests ▁and ▁the ▁THE L ▁results , ▁the ▁Army ▁began ▁updating ▁all ▁A H - 1 G , ▁- 1 Q ▁and ▁- 1 R ▁to ▁the ▁modern ized ▁A H - 1 S . ▁The ▁- 1 S ▁retained ▁the ▁Cob ra ' s