▁aircraft ▁structure , ▁they ▁cannot ▁be ▁removed ▁for ▁service ▁or ▁ins pection . ▁In spe ction ▁pan els ▁must ▁be ▁provided ▁to ▁allow ▁internal ▁ins pection , ▁repair , ▁and ▁overall ▁serv icing ▁of ▁the ▁tank . ▁Most ▁large ▁transport ▁aircraft ▁use ▁this ▁system ▁to ▁store ▁fuel ▁in ▁the ▁wings , ▁fus el age ▁and ▁emp enn age ▁of ▁the ▁aircraft . ▁ ▁R ig id ▁remov able ▁t anks ▁ ▁R ig id ▁remov able ▁t anks ▁are ▁installed ▁in ▁a ▁compart ment ▁designed ▁to ▁accommod ate ▁the ▁tank . ▁They ▁are ▁typically ▁made ▁of ▁metal , ▁pl astic ▁or ▁fib reg lass ▁construction , ▁and ▁may ▁be ▁removed ▁for ▁ins pection , ▁replacement , ▁or ▁repair . ▁R ig id ▁remov able ▁t anks ▁are ▁not ▁re lied ▁on ▁for ▁the ▁aircraft ' s ▁struct ural ▁integrity . ▁These ▁t anks ▁are ▁commonly ▁found ▁in ▁smaller ▁general ▁av iation ▁aircraft , ▁such ▁as ▁the ▁C ess na ▁ 1 7 2 . ▁Com bat ▁aircraft ▁and ▁hel ic op ters ▁generally ▁use ▁self - se aling ▁fuel ▁t anks . ▁ ▁Bl ad der ▁t anks ▁Bl ad der ▁t anks , ▁bag ▁t anks ▁or ▁fuel ▁cells , ▁are ▁rein for ced ▁rub ber ised ▁b ags ▁installed ▁in ▁a ▁section ▁of ▁aircraft ▁structure ▁designed ▁to ▁accommod ate ▁fuel . ▁The ▁bl ad der ▁is ▁rolled ▁up ▁and ▁installed ▁into ▁the ▁compart ment ▁through ▁the ▁fuel ▁fill er ▁neck ▁or ▁access ▁panel , ▁and ▁is ▁secured ▁by ▁means ▁of ▁snap