 At about 09 : 00 on 3 June , Ensign Jack Reid , piloting a PBY from U.S. Navy patrol squadron VP @-@ 44 , spotted the Japanese Occupation Force 500 nautical miles ( 580 miles ; 930 kilometres ) to the west @-@ southwest of Midway . He mistakenly reported this group as the Main Force . Nine B @-@ 17s took off from Midway at 12 : 30 for the first air attack . Three hours later , they found Tanaka 's transport group 570 nautical miles ( 660 miles ; 1 @,@ 060 kilometres ) to the west . 
