The shoulder-mounted wings were braced by a single short strut on each side, and was fitted with full span trailing edge flaps and split ailerons.

[1][2] The prototype was re-engined with 510 kilowatts (680 hp) Gnome-Rhône 14M radial engines before it made its maiden flight at Avord on 21 September 1937.

Tests showed that the aircraft was unstable, with numerous changes being made to the tail surfaces to try and rectify the problems before the prototype was badly damaged in a forced landing caused by an engine failure on 17 February 1938.

This crash-landing wrecked the fuselage of the H.220, and SNCAC, (Société Nationale de Constructions Aéronautiques du Centre), which had been formed by the merger of Hanriot and Farman as part of the nationalisation of the French aviation industry in 1937, took the opportunity to rebuild the prototype to a new design.

[1][a] The rebuilt and resigned prototype, redesignated the H.220-2, had a new fuselage, built out of two half shells joined by a central keel, with a twin-tail replacing the conventional single-fin tail surfaces of the earlier design.