Flight testing revealed some major shortcomings, most of which were not rectified before the Armistice in 1943; the low power and high wing loading resulted in poor climb performance; the light structure prevented more powerful cannon from being used as the recoil forces overstressed the mounting structure; the rear cylinders of the engine overheated during recovery from a dive; the light structure also led to problems, with the second prototype wing exploding during a dive recovery due to internal pressure built up, caused by the lack of internal fairings in the undercarriage bays; the wooden structure was also badly affected by rain or humidity.
The pre-production batch of 12 aircraft served briefly with three squadrons. The first was 83rd Squadriglia, 18 Gruppo, 3 Stormo, led by Guglielmo Specker, one of the Regia Aeronauticas best known "aces", at Cerveteri airfield, near Rome. The aircraft entered service in July 1943, flying a number of combat missions against heavy Allied raids over the Italian capital, but without success. After one month, they were sent to Castiglione del Lago G.Eleuteri airfield (at that time one of the main RA training airbases), where it was planned that 161 and 162nd Squadriglia would take the aircraft into service.
Despite its speed, Italian pilots were not impressed by the type and its service in the summer of 1943 quickly ended. The aircraft of 83rd Squadriglia were returned to SAI-Ambrosini to be refurbished, but the Armistice made it impossible for them to return to their squadron.