On 9 August 1956, the prototype G.91 conducted its maiden flight at the Caselle airfield, Turin, Italy; it was flown by Chief Test Pilot Riccardo Bignamini. Accordingly, the G.91 had achieved a seven-month head start over the Dassault prototype and almost a year ahead of the Breguet Taon. An intensive series of test flights followed the type's maiden flight, these were not without setbacks. The most serious problem discovered during these was the presence of aeroelastic vibrations, leading to a series of investigative flights to resolve this condition. On 20 February 1957, during a test flight intended to explore the limits of the aircraft's speed-load envelope, difficulties led to the destruction of the first G.91 prototype. The cause of the prototype's loss was linked to problems encountered with the horizontal control system which had led to structural failure; this led to the tail assembly being subjected to rigorous testing to identify the cause of the failure.