9 2 2 ▁were ▁" Un mod ified ▁crew ▁tra iner ". ▁Three ▁Liber ators ▁were ▁initially ▁converted ▁to ▁Liber ator ▁C . M k . I ▁( for ▁" c argo ") ▁fre igh ters : ▁( AM 9 1 5 , ▁AM 9 1 8 , ▁AM 9 2 0 ) ▁and ▁used ▁on ▁the ▁Trans at l antic ▁for ▁returning ▁aircraft ▁fer ry ▁pil ots ▁to ▁Canada ▁as ▁well ▁as ▁priority ▁ship ments ▁to ▁the ▁UK . ▁When ▁the ▁Liber ator ▁GR . Is ▁were ▁retired ▁from ▁No . ▁ 1 2 0 ▁Squadron , ▁being ▁replaced ▁with ▁later ▁marks , ▁the ▁remaining ▁aircraft ▁were ▁converted ▁to ▁Liber ator ▁C . Is . ▁ ▁AM 9 1 0 ▁was ▁used ▁to ▁assess ▁the ▁Liber ator ▁B . M k . I ▁for ▁the ▁R AF ▁in ▁July / August ▁ 1 9 4 1 ▁at ▁the ▁A & AE E . ▁It ▁was ▁then ▁used ▁for ▁testing ▁the ▁Liber ator ▁GR . M k . I ▁A XV ▁rad ar ▁and ▁ 2 0   mm ▁can non ▁install ations ▁and ▁converted ▁to ▁Liber ator ▁GR . M k . I ▁being ▁assigned ▁to ▁ 1 2 0 ▁Squadron ▁on ▁ 5 ▁September ▁ 1 9 4 1 . ▁In ▁April ▁ 1 9 4 2 , ▁it ▁crash ed ▁on ▁landing ▁at ▁R AF ▁N ut ts ▁Cor ner . ▁AM 9 1 1 ▁was ▁converted ▁to ▁Liber ator ▁GR . M k . I ▁and ▁assigned ▁to ▁