One of Leonardo Helicopters' SD-150 AWHero rotary-winged unmanned air vehicles has been severely damaged during testing.
Italian air accident investigation agency ANSV says it has opened an inquiry into the 12 June incident.
Registered I-UASF, the 180kg (397lb) maximum take-off weight AWHero came down near Nettuno, a town on the coast, around 32 miles (51km) to the southeast of Rome.
ANSV says no-one was injured in the incident, which took place during an "experimental flight", but the UAV was "seriously damaged".
Leonardo is developing the AWHero for a range of military and civil applications.