What happened
On a flight traveling from London to Naples via Airway Amber 1, a Vickers Viscount was operating at an altitude of 23,500 feet. At approximately 11:44 hours, the aircraft passed over Ostia and communicated its intention to proceed toward Ponza, with an expected arrival time of 11:57 hours.
At 11:50 hours, a collision occurred east of Nettuno between the airliner and an Italian Air Force F-86 Sabre that was participating in a group aerobatic training exercise. The impact resulted in the destruction of both aircraft. The 31 fatalities included all 26 passengers and 5 crew members on the Viscount. The pilot of the F-86 managed to escape the wreckage by parachuting to safety.
Findings
Official investigations concluded that the collision was an unavoidable event, characterized as an 'Act of God,' because neither pilot observed the other aircraft prior to the impact. A significant contributing factor was that the Viscount had deviated from its assigned airway, placing it within a restricted zone designated for military maneuvers. While some investigators suggested this deviation might have been caused by a navigational error by the crew, the primary finding focused on the lack of visual separation between the two aircraft.