Vicente Castillo Monzó was born in Benaguacil, Valencia, on 29 January 1917.

In December 1936 he joined the Arma de Aviación, enrolling in the elementary flying course at La Ribera airfield.

On 17 January 1937, the SS Ciudad de Cádiz sailed for the USSR, where they joined a pilots’ course at Kirovabad. Pilots included on the ship were Castillo, Antonio Nieto Sandoval-Díaz, José María Bravo Fernández, Antonio Arias Arias (he had previously been a volunteer in the Batallon Fernando de Rosa militia fighting on the Sierra de Peguerinos front), Francisco Meroño Pellicer and Eduardo Claudín Moncada.
Once in Kirovabad, Nieto flew Polikarpov U-2s, R-5s and I-5s.

In June 1937, pilots returned to Spain from a pilots’ course at Kirovabad in the USSR. The return entailed a sea journey from Leningrad to Le Havre and a railway trip through France. Pilots included in this trip were Castillo, Francisco Tarazona Torán, Francisco Meroño Pellicer and Eduardo Claudín Moncada.
Upon return, Castillo, Meroño and Tarazona received their pilot’s badge and the rank of sargento.

At the start of the Brunete offensive in July 1937, the Republicans had 50+ combat- ready I-15s and I-16s at their disposal.
Only one Spanish fighter unit was committed to the campaign - the 2^a Escuadrilla of the Grupo N^o 26 (I-15), commanded by the in July newly appointed CO teniente Chindasvinto González García. The unit successively moved to the airfields at Azuqueca de Henares, Caspe, Alcañiz and El Toro.
Sargento José Redondo Martín was posted to the unit in July. Sargento Castillo joined the unit on 8 July when he joined the unit at Archena airfield, in Murcia. As a member of this unit he moved to Chozas de la Sierra and took part in air combat over Brunete.

On 18 July, Sargento Castillo fought in his first aerial battle and claimed a He 51 destroyed.

On 24 August and while flying from Alcañiz, sargento Castillo claimed two CR.32 over Leciñena and Perdiguera.

In the morning on 26 August, the CR.32s escorted 19 bombers to Villamajor. Close to the bombers was the 20^a Squadriglia, while the 18^a and 19^a Squadriglie stayed above them. The weather was far from ideal and soon a layer of cloud separated the two higher flying Squadriglie from the rest. The minutes slowly ticked away as the formation moved toward the target area. Suddenly the clouds broke and Capitano Enrico Degli Incerti noticed a swarm of enemy aircraft below. Followed by his wingmen, he dived through the tattered clouds and found himself in perfect position behind an I-15. Five short bursts and the fighter began to fall. Degli Incerti followed his victim and saw it crashing into the Ebro River.
In order to gain altitude, he pulled the stick back – only to discover five I-15s at 3,000 feet, coming straight for him. His wingmen were nowhere in sight. The Republican leader, as he soon found out, was a very able pilot. He attacked the Italian at once, and while he engaged his adversary, the four other I-15s flew around them and sent bursts toward the CR.32 at close range. Bullets smashed the windscreen, tore into the parachute pack and holed the fuselage, but Degli Incerti's luck held. He threw the Fiat into a steep dive, but his foe clung to him. Bullets broke instruments on the panel and one bullet tore the belt off his waist without wounding him. Degli Incerti didn’t even try to aim anymore. He just shot wildly in the direction where a winged shadow appeared. Only three minutes went by, yet they seemed an eternity. Using all the tricks he had ever learned or heard of, he somehow managed to evade the fire of his adversaries. Then suddenly, the Republican leader’s tail came into sight. His fighter instinct made him aim and fire, but at the same second, another I-15 sent a burst into the Fiat. There was no pain, but the warmth of blood rolling down his leg made him realize that he was wounded. In desperation, he opened the throttle full, but the crippled machine didn’t respond. Glancing back, he saw a thin streak of smoke trailing him. The engine’s revolutions dropped from 2900 to 1000 and it seemed a miracle that the CR.32 was still airborne. The I-15s attacked with renewed fury and the Fiat descended more rapidly while the Republican leader closed in for the coup de grace. A hail of bullets hit the aircraft but it continued to fly. Degli Incerti noted with some relief that he had just crossed into Nationalist territory. But the attacks of his pursuers became more determined as they tried to finish him off. The I-15s opened up again and he put the Fiat’s nose down. Somehow, he managed to pull the machine out and found himself alone. He smelled smoke then felt the rapidly increasing heat of the burning fuselage. To add to his troubles, the engine suddenly stopped. Luckily, however, the ground was only a few meters below, so he switched the fuel off and landed the fighter. The burning Fiat’s tail rose into the air and then luckily fell back to the ground. Paralyzing pain knifed into his wounded leg as he tried to get out of the cockpit. However, the will for survival made his muscles move and set his body into motion out of the burning aircraft.
The 20^a Squadriglia lost two pilots when Tenente Gilberto Caselli and Sottotenente Enrico Schievano were shot down over Villamajor and killed (Caselli was shot down wounded and captured but died of his wounds in hospital). Both pilots later received a posthumous Medaglia d’oro al valor militare.
It seems that at least some of the bombers escorted by the 20^a Squadriglia were He 46s from 3-G-11 led by the unit’s CO commandante José Pérez Pardo, who was shot down and killed together with his observer Salvador Blanco. They had possibly been intercepted by I-15s from 1^a/26 led by Kapitan Anatoly Serov and it seems that they claimed three destroyed He 46s, one of them claimed by Kapitan Yevgeniy Antonov.
It also seems that 2^a/26 (I-15) took part in this combat and while flying from Alcañiz during the Belchite offensive, sargento Castillo claimed one CR.32 over Fuentes de Ebro and a Ro.37 over Caspe.
The CO of the unit, teniente Chindasvinto González García claimed two CR.32s shot down.
Sargento José Redondo Martín was mentioned in dispatches as follows:

“A major air battle over the Aragon front near Saragossa this morning ended in complete success for the Republican air force, which managed to shoot down five enemy aeroplanes - four Fiats and a Romeo - without loss to our escuadrillas. Worthy of mention in this combat is the conduct of a recently graduated sargento, José Redondo, son of the former mayor of Madrid, Cayetano Redondo. In combat with a Fiat, Redondo shot it down, despite numerous machine gun hits to his own aircraft, several of which damaged its port wing. After shooting down the Fiat Redondo flew his aircraft the considerable distance back to his airfield. The groundcrew found it hard to understand how Redondo had managed to make it to their airfield with such damage to his fighter aircraft and a serious leg wound.
The Minister of National Defence congratulated the heroic pilot, and in the presence of all the personnel of the fighter escuadrillas at the airfield, promoted him to teniente. Several captured enemy airmen stated that our offensive in Aragon had occupied a great deal of the aviation forces operating on the Santander fronts. One of the captured airmen, comandante Pérez Pardo, has a serious stomach wound and is in hospital.”

While flying from Sariñena on 2 September, sargento Castillo claimed two CR.32 over Escatrón.

On 15 October, capitán Juan José Armario Álvarez, CO of Grupo N^o 26 led a strafing attack on Garrapinillos airfield, in Saragossa. To ensure the success of this raid, the armourers worked through the night loading the aircrafts’ machine guns with incendiary ammunition.
Capitán Armario himself led the I-15s of the 1^a and 2^a Escuadrillas, which carried out the attack on the parked aircraft.
The 1^a Escuadrilla took off from Bujaraloz with twelve I-15s under the command of Kapitan Yevgeniy Antonov (Starshii Leitenant Yevgeniy Stepanov took part in this attack and Kapitan Anatoly Serov flew in the ‘Plana Mayor’).
The 2^a Escuadrilla took off with nine I-15s from Sariñena under the command of Aleksandr (?) Smirnov. Two of the pilots taking part in the attack was teniente Gerardo Gil Sánchez (CO 2^a/26) and sargento Castillo.
The I-15s were covered by the I-16 from Grupo N^o 21 that flew top cover:
1^a/21 - six I-16s from Caspe under the command of Manuel Aguirre López
2^a/21 - ten I-16s from Caspe under the command of Pleshchenko
3^a/21 - nine I-16s from Hijar under the command of (Boris) Smirnov
5^a/21 - seven I-16s from Escatrón under the command of Ivanov (and including Ivan Devotchenko)
6^a/21 - eleven I-16s from Puig Moreño under the command of Gusev
About 60 planes were claimed destroyed and damaged by the I-15s but the real total losses were only three Ju 52s, six CR.32s and three He 46s. Other aircraft were damaged by fire. The Republican aircraft only suffered one damaged I-15. This aircraft was from the 1^a Escuadrilla and it was unserviceable that afternoon.
During the attack Kapitan Serov claimed some aircraft destroyed on the ground. Kapitan Ivan Yeremenko also took part in this attack and according to some sources he led the whole attack.

On 10 December and in order to camouflage a planned Nationalist offensive towards Madrid on the Guadalajara, the Republican air forces were to be destroyed on their airfields east of Zaragoza. A Nationalist force of 88 bombers and 56 fighters took part in the operation. The slower bombers (SM.81s and Ju 52/3ms) were to attack the nearby airfields in the Barbastro zone; the faster bombers (SM.79s, Breguet 20s, He 111s and Do 17s) those at Sariñena, Bujaraloz, Candasnos, Puebla de Híjar, Selgua, Pomar, Lérida and Balaguer. The Condor Legion’s bombers, which had to operate from more distant bases, would require refuelling before making their return flight, and facilities were provided at Sanjurjo.
The attacks failed to achieve the desired success, however; the airfields were empty and about 70 fighters were waiting in the air. It must be said that the Republicans were very well prepared to deal with surprise air attacks. They had constructed a large number of airfields and at each was based at most a single squadron, its aircraft widely dispersed around the airfield perimeter. In addition, they had built a number of decoy airfield on with mock-up aircraft.
At least, the VI and XVI Gruppi of the Aviazione Legionaria took part in this combat and Tenente Corrado Santoro of the 31^a Squadriglia (VI Gruppo) took part in an escort mission to bombers attacking Sariñena and Sottotenente Mario Visintini of the 25^a Squadriglia (XVI Gruppo) took part in his first combat, firing at some enemy aircraft but without claiming anything.
At the end of the battle, the Italians claimed eight I-15s shot down for just one CR.32 lost and its pilot KIA when Sottotenente Vittorio Barberis of the 32^a Squadriglia, was killed in action near Alcubierre when his CR.32 collided with I-15 CC-022, flown by Soviet pilot Mikhail Vasilhevich Kotyhov from the 1^a/26. The latter pilot also perished.
Group 2-G-3, which was flying below the Italians, climbed to their assistance and claimed seven I-15s without losses.
1.J/88 was airborne, with 15 Bf 109s flying deep into enemy territory. They were attacked by 30 enemy fighters. Oberleutnant Harro Harder recounted:

”Another major action on December 10. The Fiats patrolled the front, we flew deep into enemy territory with fifteen Bf 109s. Fifteen Curtisses and fifteen Ratas climbed up in close formation. There was nothing else to do, we attacked repeatedly, but so many aircraft immediately dove on us that we were happy just to escape in one piece.”

In February 1938, Castillo was promoted to teniente. At the time, he was still servicing in the 2^a/26.

In early July, capitán Chindasvinto González García was appointed to lead the formerly Soviet 1^a/26 in succession to Aleksandr Osipenko, this unit being based at Manises and Requena airfields during the Levante campaign. According to one of González’ subordinates, unit deputy CO teniente Juan Sayós, he enjoyed a mixed reputation during his short period in command:

“He was a big, aggressive man. He was authoritarian and did not like his orders being questioned. He gave us instructions about our conduct over the front as if we had never been there before or as though we used to turn tail and run. We were flying a strafing mission over the Sarrión area when we noticed three or four enemy aeroplanes far in the distance. We warned the capitán about the presence of these aircraft and, although there were nine of us, he ordered us to return to base immediately. After we landed we asked him why we had not attacked those fighters. He angrily asked if we had realised that there were 15 or 20 of them. It was obvious that fear had made him see what hadn’t actually been there, and that his shouts and his aggressive behaviour was just a mask to hide his cowardice.
We were ordered to fly top cover for another escuadrilla, the 3^a de Chatos, which had to strafe enemy positions. We were over the target together and, while we flew top cover at 9000 ft, the 3^a Escuadrilla pilots dived to fulfil their mission, confident that we were covering their backs and would intercept enemy fighters. For a while it looked as though everything was going fine, but some minutes later we saw a group of Fiat fighters heading straight for us, and the capitán ordered us to retreat once again. One after another, all of us formally accused González of desertion in the face of the enemy.”

In July 1938, Castillo claimed a CR.32 between Altura and Cueva Santa during operations over Levante.

In subsequent operations over the Ebro during September teniente Castillo downed a Bf 109, which crashed in government-held territory, and a CR.32.
In November, having been promoted to capitán, Castillo was credited with his final two successes when he claimed two CR.32s destroyed over the Segre area.

In late December, capitán Castillo was appointed CO of the Grupo de Chatos N^o 26, succeeding capitán Miguel Zambudio Martínez, who had been wounded in combat on 24 December.

January 1939 saw capitan Castillo and his unit, Grupo de Chatos N^o 26, transferred to Sisones airfield, in the Central-Southern area, to participate in operations over Extremadura.
The Grupo de Chatos N^o 26 later left for Manises.

Castillo ended the Spanish Civil War as the third-ranking Spanish ace of the Republican air arm with 13 biplane victories. He had logged 550 hours and flown 350 operational sorties during the war (mostly in the I-15 Chato).

Initially confined in Santa Bárbara castle, Castillo was court-martialled at Valencia and sentenced to death. The sentence was eventually commuted to life in prison, but he was released under an amnesty in June 1943.

Castillo died in Barcelona on 16 June 1981.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	18/07/37		1	He 51	Destroyed	I-15		Brunete Front	2a/26
2	24/08/37		1	CR.32	Destroyed	I-15		Leciñena	2a/26
3	24/08/37		1	CR.32	Destroyed	I-15		Perdiguera	2a/26
4	26/08/37	morning	1	CR.32	Destroyed	I-15		Fuentes de Ebro	2a/26
5	26/08/37	morning	1	Ro.37	Destroyed	I-15		Caspe	2a/26
6	02/09/37		1	CR.32	Destroyed	I-15		Escatrón	2a/26
7	02/09/37		1	CR.32	Destroyed	I-15		Escatrón	2a/26
8	10/12/37		1	CR.32 (a)	Destroyed	I-15		From Candasnos airfield	2a/26
	1938
9	??/07/38		1	CR.32	Destroyed	I-15		Altura-Cueva	1a/26
10	??/09/38		1	Bf 109	Destroyed	I-15		Ebro area	1a/26
11	??/09/38		1	CR.32	Destroyed	I-15		Ebro area	1a/26
12	??/11/38		1	CR.32	Destroyed	I-15		Segre area	1a/26
13	??/11/38		1	CR.32	Destroyed	I-15		Segre area	1a/26

Biplane victories: 13 destroyed.
TOTAL: 13 destroyed.
(a) The Nationalist and the Italian fighters claimed to have together shot down 15 Chatos while losing only one aircraft. It seems that Republicans lost two I-15s and two I-16s, while 21 other fighters returned with various damages to their bases.

Sources:
Air War over Spain - Jesus Salas Larrazabal, 1974 Ian Allan Ltd, Shepperton, Surrey, ISBN 0-7110-0521-4
Fiat CR.32 Aces of the Spanish Civil War - Alfredo Logoluso, 2010 Osprey Publishing, Oxford, ISBN 978-1-84603-983-6
Fighter Pilots Of The Spanish Republic (Vol. 1) - Rafael A. Permuy López, Historica 36/39 no. 1, ISBN 84-87314-89-9
Spanish Republican Aces – Rafael A Permuy López, 2012 Osprey Publishing, Oxford, ISBN 978-1-84908-668-4