While tail modifications introduced to the C1 had allowed the type to enter service, a more definitive solution was provided in the form of an extended-span tailplane, which was mounted lower on the fuselage. An aircraft which had this modified tail installed, together with the fitting of additional fuel tanks within the outer wing, was predesignated as the "Hastings C2"; a further modified VIP transport variant, which was fitted with more fuel capacity to provide a longer range than standard aircraft, became the "HP.94 Hastings C4".