At the beginning of 1942, Brazil permitted the US to set up air bases in the states of Bahia, Pernambuco and Rio Grande do Norte, where the city of Natal hosted part of the U.S. Navy's VP-52 patrol squadron. In addition, US Task Force 3 established itself in Brazil, and this included a squadron equipped to attack submarines and merchant vessels attempting to trade with Japan.
Although Brazil was technically neutral, this increasing cooperation with the Allies led the Brazilian government to announce, at the Pan American States Conference in Rio on 28 January 1942, the decision to sever diplomatic relations with Germany, Japan, and Italy. As a result, from the end of January to July 1942, around thirteen Brazilian merchant vessels were sunk by German U-Boats. In August 1942, one single German submarine, the U-507, sank five Brazilian vessels in two days, causing more than six hundred deaths:
Berlin Radio pronouncements led to increasing nervousness among the Brazilian population. So unlike 1917, in 1942 it seemed that Brazilian government did not want war. In the then capital, Rio de Janeiro, the people started to retaliate against German businesses, such as restaurants. The passive position of the Vargas government was untenable in the face of public opinion. Ultimately, the government found itself with no other choice but to declare war on Germany and Italy on August 22, 1942.
The Brazilian 1st Division of the BEF was under the command of 15th Army Group of Field Marshal Harold Alexander (later succeeded by General Mark Clark), via the U.S. Fifth Army of Lieutenant General Mark Clark (later succeeded by Lieutenant General Lucian Truscott) and the U.S. IV Corps of Major General Willis D. Crittenberger. The overall organisation of the Allied and German armies in Italy at the time can be found on the Gothic Line order of battle entry.
The Brazilian Air Force component was under the command of XXII Tactical Air Command, which was itself under the Mediterranean Allied Tactical Air Force.
General Mascarenhas de Moraes (later Marshal) was the commander of the FEB with General Zenóbio da Costa as commander of the division's three regimental Combat Teams ("RCT") and General Cordeiro de Farias as commander of the Artillery.
The BEF was (theoretically) organized as a standard American infantry division, complete in all aspects, down to its logistical tail, including postal and banking services. It comprised the 1st, 6th and 11th RCTs, each one equivalent to 5,000 men having three battalions, composed of four companies each.
Soon after Brazil declared war, it began popular mobilization to create an expeditionary force to fight in Europe It took almost two years to send about 25,000 men (from an initial estimate of 100,000) to join the Allied war effort in the Italian Campaign.
In early July 1944, the first five thousand FEB/BEF soldiers left Brazil for Europe aboard the USNS General Mann. They disembarked in Naples where they waited to join the US Task Force 45. In late July, two more transports with Brazilian troops reached Italy, with three more following in September, November(1944) and February 1945. The first weeks in Italy were dedicated to acquiring the proper equipment to fight on the Italian terrain and training under American command. The troops moved to Tarquinia, 350 km north of Naples, where Clark's army was based. In November 1944, the BEF was integrated into General Crittenberger's U.S. IV Corps.
In 1944, the Italian Front resembled the multi-national force make up of the French Front in 1918. The forces fighting were constitute by: Americans (including segregated African- and Japanese-Americans), British, French, members of the British Commonwealth and French and British colonies (New Zealanders, Canadians, Indians, Gurkhas, Black Africans, Morrocans, Algerians, Jews and Arabs from the British Mandate in Palestine, South Africans), as well as Brazilians, Poles, Greeks, Czechs and anti-fascist Italians who made one of their main contributions to the Allied war effort..
The Germans made much of the presence of the Brazilian force in Italy. German propaganda included pamphlets directed to the fighting Brazilians and an hour a day radio broadcast in Portuguese from Berlin Radio called "Radio AuriVerde" (GoldenGreen Hour).
The first missions of the Brazilians were reconnaissance operations to the end of August; Brazilian troops helped to fill the gap left by divisions of the Fifth Army and French Expeditionary Corps that left Italy for Operation Dragoon, the invasion of southern France.
On September 16, the 6th RCT took Massarosa. Two days later it also took Camaiore and other small towns on the way north. By then, the BEF had already conquered Monte Prano, and controlled the Serchio valley without any major casualties. After having been in action around Barga city and after the arrival of the 1st RCT at the end of October, the BEF was directed to the base of the Apennines where it would spend the next months facing the harsh winter and the resistance of the Gothic Line.
After the Brazilians and troops of U.S. 10th Mountain Division took those positions on Apennines from February 18 to March 5, 1945 the German mass retreat had become unavoidable with the Spring offensive in April. Bologna was entered on 21 April by the Polish 3rd Carpathian Rifle Division from Eighth Army and U.S. 34th Infantry Division from Fifth Army. On the 25th a general partisan insurrection by the Italian resistance movement started at the same time as the Brazilians arrived at Parma, the Americans at Modena and Genova, and as forces of the British VIII Army advanced towards Venice and Trieste. After that, the main concern of the Allied forces in Italy was pursuing the enemy. After capturing a large number of Germans at Collecchio, the Brazilian forces were preparing to face fierce resistance at the Taro region from what was left of the retreating German army. The German troops were surrounded near Fornovo and forced to surrender. More than 20 thousand men, including the entire 148th Infantry Division, elements of the 90th Light Infantry Division (Germany), and the last former Division of Italian Fascist Army, surrendered to the Brazilian Forces on April 28.
On May 2, the Brazilians reached Turin and met French troops at the border, in Susa. Meanwhile, on the Alps, the FEB was on the heels of German forces still on the run. On that very day, the news that Hitler was dead put an end to the fighting in Italy, and all German troops surrendered to the Allies in the following hours.
The 1oGAVCA (1st Fighter Group/1º Grupo de Aviação de Caça) was formed on December 18, 1943. Commanding Officer was Ten.-Cel.-Av. (Aviation Lieutenant Colonel) Nero Moura. The group was divided into four flights: Red ("A"), Yellow ("B"), Blue ("C"), and Green ("D"). Each flight consisted of roughly twelve pilots who had been flying together. The CO of the group and some officers were not attached to any specific flight.
The group had 350 men, including 43 pilots. Unlike the FEB's Army component, the 1oGAVCA had personnel who were experienced Brazilian Air Force (Portuguese: Força Aérea Brasileira, or FAB) pilots. One of them, for example, was Alberto M. Torres, the pilot of a PBY-5A Catalina that had sunk U-199, which was operating off the Brazilian coast.
The group trained for combat in Panama, where 2o Ten.-Av. Dante (Aviation Second Lieutenant) Isidoro Gastaldoni was killed in a training accident. On May 11, 1944, the group was declared operational and became active in the air defense of the Panama Canal Zone. On June 22, the 1oGAVCA was sent to the U.S. to convert to the Republic P-47D Thunderbolt.
On September 19, 1944 the 1oGAVCA left for Italy, arriving at Livorno on October 6. It became part of the 350th Fighter Group of the USAAF, which in turn was part of the 62nd Fighter Wing, XXII Tactical Air Command, of the 12th Air Force.
The Brazilian pilots initially flew from October 31, 1944, as individual elements of flights attached to 350th FG squadrons, at first in affiliation flights and progressively taking part in more dangerous missions. Less than two weeks later, on November 11, the group started its own operations flying from its base at Tarquinia, using its tactical callsign Jambock. FAB Thunderbolts were marked by Brazilian Air Force stars, replacing the white U.S. star in the roundel.
On April 16, 1945, the U.S. Fifth Army started its offensive along the Po Valley. By then, the Group was reduced to 25 pilots, some having been killed and others shot down and captured; some others had been relieved from operations on medical grounds due to combat fatigue. The Yellow flight was thus disbanded, its remaining pilots being distributed among the other flights. Each pilot flew on average two missions a day.
On April 22, 1945, the three remaining flights took off at 5-minute intervals, starting at 8:30 AM, destroying bridges, barges, and motorized vehicles in the San Benedetto region. At 10:00 AM, a flight took off for an armed reconnaissance mission south of Mantua. More than 80 tanks, trucks, and vehicles were destroyed beyond fortified German positions. By the end of the day, the group had flown 44 individual missions, having destroyed hundreds of vehicles and barges. This was the day when more sorties than ever were made by the group; consequently, April 22 is commemorated in Brazil as Brazilian Fighter Arm Day.
The 1oGAVCA flew a total of 445 missions, 2,550 individual sorties, and 5,465 combat flight hours, from 11 November 1944 to 6 May 1945. The XXII Tactical Air Command acknowledged the efficiency of the Group by noting that although it flew only 5% of the total of missions carried out by all squadrons under its control, it accomplished a much higer percentage of the total destruction wreaked:
The soldiers buried in the FEB cemetery in Pistoia were later removed to a mausoleum built in Rio de Janeiro. The mausoleum was proposed and promoted by Mascarenhas de Moraes (then a Marshal). It was inaugurated on July 24, 1960 and covers an area of 6,850 square meters. The personnel of the BEF were regarded as a tough bunch, by the Germans and their Allied counterparts alike.
Until the BEF entered combat, the expression "a cobra vai fumar" ("snakes will smoke") was often used in Brazil in a context similar to "when pigs fly." After the war the meaning was reversed, signifying that something will definitively happen and in a furious and aggressive way.