While it demonstrated good short-field performance, the French Army's needs had changed, with it now requiring a robust utility aircraft similar to the de Havilland Canada DHC-2 Beaver.

[1][2] As a result, the company decided to develop a slightly larger version, the MH.1521 with the engine changed to a Pratt and Whitney Wasp Junior, which at 450 horsepower (340 kW) provided almost twice as much power and a slab-sided fuselage giving room for up to seven seats.

Its development was enthusiastically supported at a political level by WWII fighter ace and French war hero Pierre Clostermann, a close friend of Max Holste.

It saw service in the Algerian War as an Army cooperation aircraft, with more than 150 deployed,[6] mostly as an artillery spotter and in an air supply/ambulance role, where its good short-field performance and resistance to ground fire were required.

Its distinctive sound, made by its noisy radial engine and large propeller, was a disadvantage as the Algerian guerrillas could hear its approach long before other aircraft.