▁attached ▁to ▁No . ▁ 2 2 2 ▁Squadron ▁and ▁No . ▁ 2 2 6 ▁Squadron ▁during ▁this ▁period . ▁ ▁Transport ▁again ▁seems ▁to ▁have ▁been ▁problem atic , ▁and ▁by ▁March ▁ 1 9 1 9 , ▁he ▁was ▁still ▁in ▁Mal ta , ▁at ▁Sp in ola ▁Bay , ▁San ▁ Ġ il jan . ▁ ▁Mant le ▁was ▁now ▁offered ▁the ▁opportunity ▁to ▁see ▁action ▁on ▁the ▁C asp ian ▁Sea . ▁He ▁was ▁station ed ▁in land ▁at ▁Pet ro f ska ▁from ▁April ▁ 1 9 1 9 , ▁where ▁he ▁fle w ▁the ▁D H - 9 A ▁aircraft ▁( De hav ill and ▁two ▁se ater ▁bi plan es ), ▁as ▁part ▁of ▁the ▁British ▁movement ▁to ▁protect ▁oil ▁interests ▁in ▁B aku , ▁A zer ba ij an . ▁ ▁While ▁out ▁on ▁a ▁ra id ▁over ▁the ▁Vol ga ▁in , ▁with ▁his ▁observer , ▁Harry ▁In gram s , ▁in ▁August ▁ 1 9 1 9 , ▁their ▁plane ▁developed ▁engine ▁trouble ▁and ▁they ▁were ▁forced ▁to ▁crash ▁land ▁on ▁a ▁large ▁island ▁in ▁the ▁Vol ga ▁D elta . ▁ ▁They ▁were ▁unh urt ▁and ▁managed ▁to ▁burn ▁the ▁plane , ▁but ▁were ▁amb ushed ▁shortly ▁afterwards ▁by ▁an ▁armed ▁group ▁of ▁loc als ▁who ▁took ▁them ▁prisoner . ▁The ▁local ▁Comm iss ar ▁t ore ▁up ▁the ▁official ▁documentation ▁offering ▁a ▁reward ▁for ▁their ▁safe ▁return ▁over ▁the ▁border ▁and ▁then ▁organ ised ▁for ▁a ▁local ▁school te acher