2 0 th ▁P urs uit ▁Squadron ▁at ▁Clark ▁Field , ▁ 1 8 ▁P - 4 0 Es ▁in ▁commission ▁▁ 2 1 st ▁P urs uit ▁Squadron ▁at ▁Nich ols ▁Field , ▁had ▁ 1 8 ▁P - 4 0 B s ▁in ▁commission ▁▁ 3 4 th ▁P urs uit ▁Squadron ▁at ▁Del ▁Car men ▁Field ▁had ▁ 1 8 ▁P - 3 5 As ▁in ▁commission ▁▁ 8 ▁December ▁ 1 9 4 1 ▁On ▁ 8 ▁December ▁at ▁about ▁ 0 3 : 3 0 ▁the ▁commercial ▁radio ▁station ▁at ▁Clark ▁Field ▁intercept ed ▁a ▁message ▁from ▁Pear l ▁Har bor , ▁Hawai i ▁about ▁the ▁Japanese ▁attack ▁there . ▁ ▁However ▁the ▁group ▁was ▁unable ▁to ▁verify ▁this ▁inter ception ▁through ▁official ▁channels , ▁no ▁other ▁action ▁was ▁taken ▁other ▁than ▁not ifying ▁the ▁Base ▁Commander . ▁ ▁However , ▁all ▁squad rons ▁were ▁put ▁on ▁alert . ▁ ▁At ▁about ▁ 0 4 : 0 0 ▁the ▁rad ar ▁at ▁I ba ▁Field ▁reported ▁a ▁formation ▁of ▁un ident ified ▁aircraft ▁approximately ▁ 7 5 ▁miles ▁off ▁the ▁West ▁Coast ▁of ▁Lu zon ▁heading ▁towards ▁Cor reg idor . ▁ ▁The ▁ 3 d ▁P urs uit ▁Squadron ▁was ▁dispatch ed ▁to ▁intercept ▁the ▁formation , ▁but ▁no ▁plan es ▁were ▁sight ed ▁and ▁the ▁squad ron ▁returned ▁to ▁I ba . ▁ ▁However , ▁the ▁rad ar ▁tracks ▁showed ▁the ▁inter ception ▁was ▁successful ▁and ▁the ▁un ident ified ▁aircraft ▁sw ung ▁off ▁to ▁the