In 1928 SISA took delivery of l-AABN, its first example of the three-engined CANT 22, powered by a trio of 200 h.p. Isotta-Fraschini Asso 200 six-cylinder inline engines in tractor configuration. Named San Marco in SISA service, l-AABN was later absorbed into the state-owned Societa Aerea Mediterranea and ultimately, Ala Littoria.

CANT 22 I-ALFA (c/n 230) was named San Sergio in SISA service and joined the company in June 1931. An unequal-span biplane with a single-step wooden hull and single fin and rudder, the type was fitted with two side-by-side cockpits situated midway between the wings and the bow.

The passenger cabin was aft of the cockpits and incorporated three large rectangular windows in each side. The CANT 22 was comfortable and operated on SISA’s Trieste-Genoa and Trieste-Ancona routes.