▁the ▁Mem or and um ▁on ▁the ▁Dis pos al ▁of ▁M embers ▁of ▁Air ▁C rew s ▁Who ▁For fe it ▁the ▁Conf idence ▁of ▁Their ▁Command ing ▁Offic ers ▁S . 6 1 1 4 1 / S . 7 . C ( 1 ) ▁issued ▁on ▁ 2 8 ▁September ▁ 1 9 4 0 , ▁signed ▁by ▁Charles ▁Evans , ▁Princi pal ▁Ass istant ▁Secretary ▁for ▁Person nel ▁in ▁the ▁Air ▁Ministry . ▁This ▁" LM F ▁memor and um " ▁was ▁re vised ▁in ▁ 1 9 ▁September ▁ 1 9 4 1 , ▁ 3 ▁February ▁ 1 9 4 3 ▁and ▁ 1 ▁March ▁ 1 9 4 5 . ▁ ▁Under ▁this ▁procedure , ▁air cre w ▁ref using ▁to ▁fly ▁operations ▁were ▁to ▁be ▁class ified ▁as ▁( i ) ▁med ically ▁fit , ▁( ii ) ▁med ically ▁un fit ▁on ▁nerv ous ▁grounds ▁( int rodu ced ▁in ▁the ▁ 1 9 4 1 ▁revision ) ▁or ▁( iii ) ▁med ically ▁un fit ▁for ▁other ▁reasons . ▁Air cre w ▁would ▁not ▁be ▁placed ▁in ▁the ▁first ▁two ▁categories ▁if ▁they ▁had ▁been ▁subject ▁to ▁" exception al ▁flying ▁stress ", ▁and ▁to ▁be ▁assigned ▁to ▁category ▁( i ), ▁they ▁" had ▁to ▁be ▁proved ▁to ▁be ▁lack ing ▁in ▁moral ▁fib re ". ▁From ▁February ▁ 1 9 4 3 , ▁air cre w ▁on ▁their ▁second ▁tour ▁( 3 0 ▁operations ▁in ▁Bom ber ▁Command ) ▁could ▁not