On the last day of August 1940, the 151^o Gruppo C.T. (366^a, 367^a and 368^a Squadriglie) was ordered to move in Libya with 30 CR.42s as a reinforcement for the attack against Sidi Barrani.
The unit under the command of Maggiore Carlo Calosso was one of the first equipped with CR.42s in 1939 and was based in Caselle Torinese near Turin, with sections and Squadriglie detached in different airbases of North Italy for local defence duties.
They departed Caselle Torinese in the morning of 6 September and at 18:20 on 8 September, the whole Gruppo landed in Tripoli Castel Benito.
The 366^a Squadriglia formation was composed of ten aircraft: Capitano Bernardino Serafini (CO), Tenente Mario Ferrero (the Gruppo Adjutant), Sottotenente Amedeo Guidi, Maresciallo Giulio Cesare, Sergente Maggiore Fiorenzo Milella, Sergente Maggiore Dino Carta, Sergente Maggiore Roberto Marchi, Sergente Maggiore Cesare Chiarmetta, Sergente Antonio Camerini, Sergente Eugenio Cicognani. Tenente Piero Veneziani and Maresciallo Giovanni Accorsi followed in the unit’s hack Caproni Ca.133 together with five ground personnel.
The formation of 367^a Squadriglia comprised the Gruppo Commander Maggiore Carlo Calosso, the 368^a Squadriglia’s pilot Sergente Piero Hosquet and nine other pilots for a total of eleven. Among them were Capitano Simeone Marsan (the CO), Tenente Irzio Bozzolan, Tenente Aldo Bonuti, Sergente Maggiore Gino Bogoni and Sergente Tolmino Zanarini. The Squadriglia’s other six pilots were Tenente Giuseppe Costantini, Maresciallo Bruno Castellani, Sergente Maggiore Rodolfo Benco, Sergente Maggiore Bruno Celotto, Sergente Renato Mingozzi and Sergente Maggiorino Soldati.
The 368^a Squadriglia formation was composed of nine aircraft: Capitano Bruno Locatelli (CO), Tenente Giuseppe Zuffi, Sottotenente Furio Lauri, Sergente Maggiore Davide Colauzzi, Sergente Maggiore Annibale Ricotti, Sergente Maggiore Alvise Andrich, Sergente Stefano Fiore, Sergente Ambrosi, Sergente Mario Turchi. Tenente Orfeo Paroli and Maresciallo Guido Paparatti followed in the Ca.133 of the Squadriglia (Paroli and Fiore were just transferred from 367^a Squadriglia).
On 25 September the 151^o Gruppo transferred from Benghazi to El Adem where it replaced the 9^o Gruppo C.T.

In the afternoon on 9 December, SM 79s were out to bomb British troops at the Sidi Barrani - Bir Enba area. They were to be escorted by 19 CR.42s of the 9^o Gruppo led by Maggiore Ernesto Botto, which had taken off from El Adem at 14:55. The fighters included seven from the 73^a Squadriglia (Tenente Valerio De Campo (CO), Tenente Giulio Reiner, Sottotenente Alvaro Querci, Sergente Maggiore Guglielmo Biffani, Sergente Maggiore Enrico Dallari, Sergente Maggiore Antonio Valle and Sergente Santo Gino) seven from the 97^a Squadriglia (Capitano Antonio Larsimont Pergameni (CO), Tenente Ezio Viglione Borghese, Sottotenente Riccardo Vaccari, Sergente Maggiore Otello Perotti, Sergente Maggiore Massimo Salvatore, Sergente Angelo Golino and Sergente Alcide Leoni) and four from the 96^a Squadriglia (Tenente Aldo Gon and Sergente Giuseppe Tomasi together with two unknown pilots).
More Italian fighters were up to escort the bombers and at 15:10, Sergente Maggiore Fiorenzo Milella of the 366^a, 151^o Gruppo, attached to a formation of nine CR.42s of the 368^a Squadriglia (Capitano Bruno Locatelli, Sergente Maggiore Davide Colauzzi, Sergente Ernesto De Bellis, Sottotenente Furio Lauri, Sergente Maggiore Annibale Ricotti, Tenente Orfeo Paroli, Sergente Piero Hosquet, Sergente Stefano Fiore, Sergente Ambrosi) were out to escorted Italian bombers in the Bir Enba area.
The rendezvous with the bombers over A3 failed and after 20 minutes, the fighters of the 9^o Gruppo arrived and together they proceeded towards the front on a free sweep. Three SM 79s were discovered and escorted for a while. Over Buq-Buq, a Hurricane strafing along the coastal road was discovered and the SM 79s were left to the 9^o Gruppo while the CR.42s of the 151^o Gruppo attacked the British fighter. The Hurricane was claimed shot down in flames and credited to the formation (but in fact only Locatelli, Lauri, Paroli and De Bellis fired their guns).
The 151^a Gruppo fighters returned to base at 16:50.
Meanwhile the fighters from the 9^o Gruppo continued and 30 km south of Bir Enba they spotted some Gladiators at a lower level and dived on them, but suddenly the CR.42s were jumped by a reported two Squadrons of Hurricanes or Spitfires, attacking respectively the 73^a Squadriglia and the 96^a Squadriglia with the 97^a Squadriglia. A large dogfight started and after 20 minutes of combat many claims were submitted by the Italian pilots
Tenente Vaccari fought alone against four Hurricanes, claiming one destroyed (as a Spitfire) and damaging the others before his Fiat was hit in the fuel tank and in the engine. He crash-landed near Sollum, the aircraft turning over and caught fire; he was burned in the face and hands. Sergente Maggiore Salvatore claimed a Spitfire and several damaged before being wounded in his left arm. He managed however to return to base. Sergente Golino was hit in his back, but managed to claim his attacker before being compelled to evade and land at Amseat A3. Sergente Maggiore Biffani (Fiat CR.42 MM5599/73-9) claimed a Hurricane but was at the same shot down by his victim and was captured. He recalled:

"In the afternoon of 9 December we were flying between Mersa Matruh and Buq-Buq, when my wingman, Sottotenente Alvaro Querci, warned me that we had enemies behind us. I alerted Botto by shooting a burst [Note that the CR.42 had no radio during this period], then I realized they were near my tail, so I made a 180-degree turn and I saw them pass: they were three Hurricanes. I climbed almost vertically and saw the 73^a Squadriglia in front, the three Hurricanes behind it and 96^a and 97^a Squadriglia behind them, all in a vertical line that went down to the ground. Then I discovered a Hurricane that was breaking off from the combat, clearly he had seen the other Italian fighters on its tail. I continued to climb, now I was the highest fighter of them all, then I dived down at full throttle [towards the escaping Hurricane]. I arrived near it and then I reduced speed and put the revolutions between 1850 and 2250 because otherwise I would had cut my propeller as happened to Gon and others, because the airscrew went out of gear and the round was fired when it passed in front of the gun (…) . When I closed to it, I opened fire. I aimed and saw the explosive bullets that exploded on the wing. Why didn’t anything happen? Was there no fuel at all? I fired at the other wing but it was the same, the bullets exploded but nothing happened. I fired into the engine, nothing happened. I saw the tracers very well, and after all, it wasn’t the first time I was shooting. At Gorizia I used to hit the target balloon with ten rounds only. In the meantime, I was losing speed and falling behind, O.K. Goodbye! It passed and turned towards me again -so I hadn’t caused any damage to it- , and I did the same. We found ourselves face to face at a distance of around 500-600 metres. I started firing and saw my tracers hitting it, then its wings lit up and in the same moment my plane caught fire, it was just an instant. My plane was severely damaged and while I was trying to land I saw the Hurricane that dived into the ground and exploded. I saw no parachute. I force-landed among British MTs and was immediately taken prisoner. I went back home after 63 months of POW!"

“The enemy engaged in dogfight. Claim one E a/c for certain (saw it hit the ground). Attacked two in tight vic and was at 200 yards point blank range and fell certain must have killed pilots. Got another good and point blank deflection shot at another. Closed from optimum to point blank range at first. Must (?) have shot down the first two but could not spare time to confirm. 3rd point blank deflection shot likely and fourth adversary saw it hit the ground (claim 1 confirmed and 2 others which I feel certain about but must go down as unconfirmed).”

“The enemy fired back. 1 CR 42 shot down and seen to hit the ground without burning. Several other machines were shot at individually. They can out manoeuvre a Hurricane but one can get away and then come back.”

“The enemy tried to turn inside me. 1 CR 42 shot at short range from above into cockpit. Aircraft turned (unreadable) with sparks from it. Followed it down until attacked by others CR 42s. Using 15^o flap climb (unreadable) but not quite equal to 42. Speed on level far superior. Possible when attacked from above to turn and deliver short head on burst.”

“The enemy dog fought, during dogfight damaged two enemy and sent one down out of control but could not see it crash as another was in my tail. The enemy fairly aggressive.”

“The enemy started a general dogfight. 1 CR 42 shot down and seen to burn out on the ground”.

Between 15:30 and 15:45 on 10 December, a formation from the whole 151^o Gruppo took off from A3 to escort Ba.65s in the Bir Enba – Sidi Barrani area. The 366^a and 367^a Squadriglie flew direct cover of the assault aircraft while the 368^a Squadriglia acted as top cover.
Pilots from 366^a Squadriglia were Capitano Bernardino Serafini, Tenente Guglielmo Chiarini, Sottotenente Amedeo Guidi, Sottotenente Carlo Albertini, Sergente Maggiore Cesare Chiarmetta, Sergente Maggiore Fiorenzo Milella and Sergente Antonio Camerini. Pilots from the 368^a Squadriglia were Capitano Bruno Locatelli, Sergente Maggiore Davide Colauzzi, Tenente Orfeo Paroli (aborted due to mechanical problems), Sergente Ambrosi, Tenente Giuseppe Zuffi, Sergente Mario Turchi and Sottotenente Furio Lauri together with Maresciallo Giulio Cesare of the 366^a Squadriglia. Not all the participating pilots from the 367^a Squadriglia are known but included were Capitano Irzio Bozzolan, Sergente Maggiore Rodolfo Benco, Sergente Maggiore Gino Bogoni, Sergente Tolmino Zanarini, (plus possibly other three pilots).
After the attack of the Bredas, the close escort Squadriglie went down to strafe. The 366^a Squadriglia did five passes and then it was the turn of the 367^a Squadriglia. The weather in the meantime was again deteriorating and was not possible to maintain visual contact between the two covering Squadriglie and the strafing one.
Because of this, the 367^a Squadriglia was surprised from astern by a formation of Glosters while intent in strafing. After a short combat the CR.42s were able to disengage, claiming only a probable victory by an unknown pilot but losing Sergente Bogoni’s CR.42 and getting Sergente Maggiore Benco’s (wounded in the right foot) and Sergente Zanarini’s fighters damaged. Capitano Bozzolan had a narrow escape when pursued by two Gladiators that damaged his engine; he was forced to land in the midst of the enemy armoured cars with a stopped engine. Suddenly the Fiat A74 engine restarted and Bozzolan was able to do a touch-an-go, just managing to return to A3.
They had run into Gladiators from 3 RAAF Squadron. Five Gladiators piloted by Squadron Leader Ian McLachlan, Flight Lieutenant Gordon Steege, Flying Officer Alan Gatward, Flying Officer B. L. Bracegirdle and a fight unknown pilot (the ORB only names four pilots but all combat reports states five Gladiators) had taken off from ALG 74 at 15:40 to carry out an offensive patrol over Tummar. They reported encountering twelve CR.42s that were ground strafing Allied troops near Tummar West. The Gladiators attacked the enemy aircraft and in the ensuing battle, Squadron Leader McLachlan shot one down which he saw strike the ground whilst Flight Lieutenant Steege and Flying Officer Gatward each got a possible. These were later confirmed. All Gladiators returned to base at 17:10. According to some sources Steege and Flying Officer Gatward each claimed 1 and 1 probable CR.42 in this combat, but this can’t be verified with 3 RAAF Squadron’s Operations Record Book nor the combat reports.
Flight Lieutenant Steege reported:

”5 Gladiators led by me were flying at 2000 ft [600 meters] on an Westerly Course about 2 Miles [3.2 kilometres] ENE of NEBEIWA at 1645 when Aircraft were observed Dive Bombing The road running N – South beside the West Edge of West Tummar.
E.A. were carrying an orthodox D. B. from about 3000 ft [900 meters].
Own formation climbed into sun. During this, one E.A. climbing from an attack evidently saw our formation as he continued to climb S.E. I climbed after him and saw my incendiaries passing around him. He stalled to the right as I did, about 500 feet [150 meters] below him.
The remained of own formation were then also engaging E.A.
I followed another from astern at 4000 ft [1,200 meters] and got in several good bursts. He was climbing slowly and appeared to attempt to turn into a head on attack. I fired a long burst into him from about 150 yds [140 meters] and he went into a steep spiral dive 3 turns of which I counted. I then lost sight of him.
During the engagement 5 S 79s were seen to pass above W. Tummar on a West Course at about 7000 ft [2,100 meters] but it was not practical to chase them.”

”When diving from [unreadable] towards E.A. I saw one E.A. proceeding WEST low down on my starboard. I dived on him from the beam and followed him round until almost directly astern & slightly above. I opened fire at a range of approx 50 yds [45 meters] and after a short burst E A which was flying straight at about 200 ft [60 meters] slewed right and dived into the ground. I saw E.A. strike the ground in a cloud of dust and then turned away to avoid another E.A. I had not seen E.A. burning. I returned EAST to [incomprehensible].”

”Own formation attacked out of sun and appeared to be observed by two E.A. only.
I arrived over the area to find three E.A. in echelon about 500 ft [150 meters] below me, apparently preparing for another dive bombing attack on target.
By half rolling and diving I came astern the last aircraft at about 150 yards [137 meters] where I opened fire. The aircraft when fired on commenced a very steep climbing turn from which it spun away. I was unable to observe the result of this spin as by this time I was in the middle of a fight and was taking avoiding action. I followed another aircraft out to the NORTH but was quickly outdistanced by his superior speed. I returned to the scene of the fight but the E.A. had gone home and our formation formed up again.”

On 9 July 1941, seven Blenheim IVs from 110 Squadron took off from Luqa, Malta, to attack Axis shipping in Tripoli harbour. The Blenheims claimed direct hits on four merchant vessels, one which was estimated to be 12,000 tons, two of 10,000 tons and one of 7,000 tons. Losses were heavy however, four Bleheims failing to return. Squadron Leader D. H. Seale (Z6449; crew Flight Sergeant F. B. Mulford and Flight Sergeant W. H. McDougall) was seen to force-land in the sea while Pilot Officer W. H. Lowe (Z9578; crew Sergeant R. E. Baird and Sergeant H. Lummus) was short down and they were reported missing and KIA with their crews. Flight Lieutenant M. E. Potier (Z9537) was shot down and killed while his crew of Pilot Officer T. Griffith-Jones and Sergeant D. H. Wythe became prisoners. Sergeant W. H. Twist (Z9533) was shot down a few miles north of Tripoli, he and his crew (Sergeant D. W. Allen and Sergeant S. W. Taylor) becoming prisoners.
Italian fighters had been scrambled in time and managed to intercept the bombers effectively. Flying at 1,500m at about 16:00 Maresciallo Aldo Buvoli (G.50bis MM6384) from the 378^a Squadriglia spotted a formation of four Blenheims, followed at a distance by a fifth. He shot down one over the port and a second over the sea after a long chase. Two CR.42s from the 151^o Gruppo flown by Maresciallo Paolo Montanari of the 366^a Squadriglia and Sergente Ambrosi of the 368^a Squadriglia also intercepted the bombers claiming one shot down each.
Ambrosi was later awarded the Medaglia di bronzo al valor militare.

Ambrosi ended the war with 1 biplane victory, this one claimed while flying the Fiat CR.42.
Ambrosi was also awarded the Medaglia d'argento al valor militare during the war.

Ambrosi passed away on 11 August 1990.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
	09/12/40	15:10-16:50	1/10	Hurricane (a)	Shared destroyed	Fiat CR.42		Buq-Buq	368a Squadriglia
	10/12/40	15:40-	1/5	Hurricane (b)	Shared damaged	Fiat CR.42		Sidi Barrani - Buq-Buq	368a Squadriglia
	1941
1	09/07/41	16:00 ca	1	Blenheim (c)	Destroyed	Fiat CR.42		Tripoli area	368a Squadriglia

Biplane victories: 1 and 1 shared destroyed, 1 shared damaged.
TOTAL: 1 and 1 shared destroyed, 1 shared damaged.
(a) Probably claimed in combat between 9^o and 151^o Gruppi and 33 and 274 Squadrons. 9^o Gruppo claimed eight shot down, three probables and several damaged while losing two CR.42s and four force-landed. The 151^o Gruppo claimed one Hurricane without losses. 33 and 274 Squadrons claimed seven or eight CR.42s and three probables while one Hurricane (33 Squadron) had to force-land and a second (274 Squadron) was damaged.
(b) Possibly a Hurricane from 33 Squadron; Lieutenant Jacobus George Fischer KIA.
(c) Claimed in combat with Blenheims from 110 Squadron, which lost four Blenheims corresponding with four Italian claims.

Sources:
53^o Stormo - Marco Mattioli, 2010 Osprey Publishing, Oxford, ISBN 978-1-84603-977-5
Aces High - Christopher Shores and Clive Williams, 1994 Grub Street, London, ISBN 1-898697-00-0
A History of the Mediterranean Air War 1940-1945: Volume One – Christopher Shores and Giovanni Massimello with Russell Guest, 2012 Grub Street, London, ISBN 978-1908117076
Desert Prelude: Early clashes June-November 1940 - Håkan Gustavsson and Ludovico Slongo, 2010 MMP books, ISBN 978-83-89450-52-4
Desert Prelude: Operation Compass - Håkan Gustavsson and Ludovico Slongo, 2011 MMP books, ISBN 978-83-61421-18-4
Hurricanes over Tobruk - Brian Cull with Don Minterne, 1999 Grub Street, London, ISBN 1-902304-11-X
Malta: The Hurricane Years 1940-41 - Christopher Shores and Brian Cull with Nicola Malizia, 1987 Grub Street, London, ISBN 0-89747-207-1
Additional information kindly provided by Gianandrea Bussi and Ludovico Slongo.