Even if SM.79s were considered overall to be quite sturdy and well-developed aircraft, they had their share of misfortune.
In Spain, SM.79 MM.28-16 (with a total crew of 17) was destroyed in the air on 12 April 1938, when one of its bombs detonated in the bomb bay. MM.28-25 (again with a crew of 17) was lost when another SM.79 damaged by anti-aircraft guns collided with it on 23 March. A further SM.79, MM.28-16 was damaged by an anti-aircraft shell, and landed with dead and wounded on-board (4 January 1939). On 30 June 1939 two of the aircraft, 13-6 and 13-7, both carrying a full fuel load, collided and crashed, with the entire crew of nine killed on impact.
At the beginning of World war II, on 13 June 1940, six Sparvieros of 9th Wing bombed Ghisonaccia airfield, but one was shot down by anti-aircraft guns and became the first Sparviero downed in World War II.
The 9th Stormo continued to suffer heavy losses in Africa. Initially used to harass light forces operating in the desert, the Sparvieros were subsequently sent against the British advanced columns in Operation Compass. On 16 December 1940, six Sparvieros were sent over As Sallum to counter enemy armoured units, but before they could reach their target, three of the lead section were shot down with the loss of 16 men, including Commander Mario Aramu. The wing was put out of action and the personnel were sent back to Italy aboard the RM Città di Messina, but on 14 January 1941 the ship was sunk by submarine HMS Regent, with the loss of 432 men, including 53 members of the 9th. The wing was later re-formed with Z.1007s.
A major safety issue in the operation of the SM.79 was the difference between the calculated and effective range figures, which led to several mishaps. Two accidents highlight the deficiencies in range of the Sparvieros.
One such incident befell MM.23881 of the 278th, which took off at 1725 hours on 21 April 1941, captained by Oscar Cimolini, with the intention of searching for enemy shipping near Crete. The SM.79 carried out an attack at around 20:00 hours, and then began the trip back to its base near Benghazi. The crew became disoriented and unable to locate their exact position, missing their airfield in bad weather conditions. Their radio was broken and they were unable to communicate. They were also unaware that they had reached the African coast. The fuel supply was exhausted at around 23:00, and the aircraft made a forced landing some 500 km (310 mi) away from its base. Most of the crew of six had suffered some injuries, but one crew member, Romanini, was able to leave to search for help. He walked for over 90 km (60 mi) in the desert, and finally was overcome and died only a few kilometres from a road, where his remains were found in 1960. Subsequent searches led to the discovery of the SM.79 and the remains of the rest of the crew.
Another example was the ferry flight of 27th Gruppo. This unit was transferred from Alghero to North Africa. The 16 Sparvieros took off at 11:50 of 4 April 1941, but one of the eight aircraft of the 18th Squadriglia in the first wave had an accident and crashed on the airport strip. The other eight from 52nd Squadriglia could only take off 40 minutes later, while the first seven circled over the airfield. The 15 Sparvieros flew together until reaching Misurata, but the 18th squadriglia had flown for much longer and was short of fuel. Subsequently, its SM.79s crashed one after the other with only two landing safely. At least two were completely destroyed, and three damaged. On that day, on a simple ferry flight of 1,100 km, the 18th lost five Sparvieros and at least one crew, with many wounded. The flight of 52nd Sq lasted for 4 hours and 45 mins but 18th Sq flew for 5h and 15 mins, without any payload, at an average speed of only 210 km/h.
9–11 July 1940: Battle of Calabria, one SM.79 (38th Gruppo) was downed by a Blackburn Skua of HMS Ark Royal. On 11 July, another SM.79 (90th Gruppo) was downed by a Gloster Sea Gladiator of HMS Eagle.
1 August 1940: an SM.79 was shot down by a Skua from Ark Royal. This was General Cagna's aircraft.
2 September, Operation Hats: the new Fairey Fulmar fighters based on HMS Illustrious downed a 41 Stormo SM.79.
4 September: another SM.79 (34th Gruppo) was downed by Fulmars.
12–14 October 1940, Operation MW 2: two SM.79 (36th Stormo) were downed by Fulmars from Illustrious.
10 January 1941, Battle of Taranto: a single Fulmar from Illustrious downed two SM.79s of 30th Stormo.
20–22 April 1941: one SM.79 (278th Squadriglia, torpedo unit) was shot down on the 21st, another, from 34 Gruppo was shot down the next day, by Fulmars from HMS Formidable
8 May 1941, Operation Tiger: two SM.79s (38thGruppo) were downed by the Ark Royal's Fulmars
21–25 July 1941, Operation Substance: 23 July, one SM.79 (38th) and two (283rd) torpedo bombers and on the 25th, one SM.79 (89th Gruppo) were shot down, all by Fulmars from Ark Royal.
12–17 June 1942, Operation Harpoon: Fulmars and Sea Hurricanes downed four SM.79s of 36th Stormo (torpedo-bombers) on 14 June. On 15 June another SM.79 (52nd Gruppo) was shot down.
10–15 August 1942, Operation Pedestal: two SM.79s (109th and 132nd Gruppo) were downed on 12 August.
The total number of reconnaissance, bomber and torpedo bombers downed in these two years by naval fighters was, not counting aircraft heavily damaged and eventually lost, 24 aircraft, 2% of total production.