On 17 April 1937, the three Nationalist He 51 escuadrillas operated over the Teruel front with a total of 17 fighters.
2-E-2, with five He 51s, saw an enemy bomber but was unable to close with it. Shortly after they were joined by another He 51, flown by teniente Jaime Palmero Palmeta, and caught sight of ten I-15s patrolling well above their own altitude of 4,000m. They climbed to attack, determined to break off at the moment of interception, but teniente Palmero was unable to evade one I-15 that was coming down very fast in a dive, and the two machines collided. The ensuing combat ranged all over the sky, and ten more I-15s and a third fighter squadron soon joined the battle against the five remaining aircraft of 2-E-2. Capitán Ángel Salas Larrazábal made attacks on four aircraft but didn’t claim anything and arrived at Calamocha with his petrol tanks almost dry and with 18 bullet holes in the fuselage and wings. He had remained in the combat area until all the Republican fighters had disappeared. Alferéz Jorge Muntadas Claramunt, alferéz Rafael Mazarredo Trenor and alferéz Joaquín Ansaldo Vejarano had already landed at Calamocha, and only Ansaldo’s aircraft was free from damage. The fifth pilot, alférez Javier Allende Isasi was shot down by alferéz Juan Comas Borrás of 2^a/16. Allende’s fighter was seriously damaged and chivalrously escorted by Comas it until Allende was able to make a forced-landing in Nationalist-held territory.
2-E-2 had alone been involved in this combat, the other two He 51 escuadrillas were unaware of the action and were patrolling peacefully over their own lines.
Nationalist observers on the ground saw seven aircraft fall, and if one discounts the two He 51s flown by Palmero and Allende, this gives the destruction of five I-15s, but the Nationalist communiqué claimed a total of seven aircraft destroyed.
It seems that 18-21 I-15s were involved since it’s known that three escuadrillas took part in the combat; 1^a/16 (Escuadrilla La Calle), 2^a/16 and Escuadrilla Kazakov (the two last escuadrillas operated from the same airfield near Sarrion) and five claims are known. The 2^a/16 was first to engage, followed by Escuadrilla Kazakov and finally by the 1^a/16.
Additional to Comas’ claim of Allende, Albert Baumler (Escuadrilla Kazakov) reported that on his second mission of the day, his group intercepted a formation of Heinkel He 51 pursuits. Giving chase to the enemy, Baumler crippled a Heinkel; as he did not see it crash, he was awarded with only a probable victory. He did, however, obtain credit for a subsequent "kill" in this same combat. Aleksandr Osadchiy, CO of Escuadrilla Kazakov claimed two He 51 while Frank Tinker from the 1^a/16 claimed a He 51while flying in I-15 CA-058.
The I-15 that collided with teniente Palmero was flown by Alfonso Calvo Ortíz of the 2^a/16, who also was killed.
It seems that Manuel Aguirre Lopez of Escuadrilla Kazakov also took part in this combat but without claiming anything.

The all-Spanish Fiat Grupo, with the designation 2-G-3, was formed in Cordoba on 4 May 1937 from the escuadrillas led by capitán Joaquín García Morato and capitán Ángel Salas (2-E-3). Morato assumed command of the Grupo, and Julio Salvador took over leadership of Morato’s old escuadrilla (1-E-3).
This had been made possible after a further consignment of eight CR.32s had been passed on to the Nationalist air force in April 1937, and they joined the five previously handed over four months earlier to form the basis of the first Spanish grupo equipped with Fiat fighters. Grupo 2-G-3 consisted of 13 aircraft and 15 pilots, which were divided into two escuadrillas of six fighters each. The final CR.32 was Morato’s personal (3-51).
Of the pilots assigned to its escuadrillas, two of them had previously served as wingmen in the Patrulla Azul, while the remaining 12 were chosen according to their experience in fighters.

Escuadrilla 1-E-3
Teniente Julio Salvador (CO)
Teniente Miguel Guerrero García
Alférez Manuel Vázquez Sagastizábal
Alférez Arístides García López Rengel
Alférez Rafael Mazarredo Trenor
Alférez Jesús Rubio Paz
Brigada Ramón Senra Ŕlvarez

Escuadrilla 2-E-3
Capitán Ángel Salas
Capitán Narciso Bermúdes de Castro
Capitán Javier Murcia Rubio
Teniente Miguel García Pardo
Alférez Javier Allende Isasi
Alférez Joaquín Ansaldo Vejarano
Alférez Muntadas

On 28 December, 16 fighters from Grupo 2-G-3 clashed with nine I-15s and 12 I-16s directly above Teruel. Nationalist pilots were credited with shooting down four ‘Curtiss fighters’ and a Rata for the loss of Antonio López Sert (3-87) of Escuadrilla 1-E-3 (reportedly to small-arms fire). Teniente Carlos Bayo Alessandri (2-E-3) attacked a Chato head-on, scoring some hits. He made a second attack from astern and the enemy fighter began to lose height and crashed behind Republican lines near Villastar. Alférez Javier Allende Isasi (2-E-3) claimed two I-15s while alférez Muntadas (2-E-3) claimed the fourth I-15 and alférez Manuel Vázquez Sagastizábal (1-E-3) claimed the I-16.
It seems that at least the 3^a/26 (I-15) was involved in this combat and they claimed four CR.32s during the day. The CO of the unit, teniente Juan Comas Borrás claimed two CR.32s while sargento Francisco Montagut Ferrer and Rafael Sanromá Daroca claimed one each.
The Republicans admitted the loss of teniente José M.^a Campoamor Peláez, who fell with his burning I-15 in the vicinity of La Muela, while two other aircraft returned to base damaged.

26 P-Zs, escorted by 26 fighters, bombed ground troops twice in the Barrios de San Blas area on 5 January 1938.
The first mission was not intercepted but during the second, at around 15:00, they were intercepted by Fiat CR.32s and Bf 109s.
Leitenant Aleksey Loskutov was shot down and killed in his I-15. It is possible that Loskutov in fact was flying in I-16 CM118 from 5^a/21 since this is the only Republican loss reported during the day.
The gunners in the R-Zs reported that one CR.32 was shot down from which the pilot parachuted and landed in Nationalist territory. The Republican fighters claimed three CR.32s and one Bf 109. Only two claimants are known and flying from El Toro airfield, capitán Chindasvinto González García, CO 2^a/26, claimed a Bf 109 destroyed as his final recorded aerial victory while Emilio Ramírez Bravo from the same unit claimed a damaged CR.32.
The Italians reported that in the afternoon, Maggiore Andrea Zotti led 16 CR.32s from XXIII Gruppo on a surveillance patrol over Teruel. The aircraft intercepted a formation of R-Zs and claimed five shot down. One was credited to the gruppo’s second-in-command, Capitano Guido Nobili.
Oberfeldwebel Ignaz Prestele of 1.J/88 (Bf 109) claimed one I-16 in the same combat.
The only known Nationalist loss is a damaged CR.32 when Muntadas from 2-G-3 made an emergency landing at his home airfield.

On 4 May, Commander Ángel Salas of 2-G-3 had his fuel and water tanks holed by machine-gun fire from the ground, forcing him to make an emergency landing at Aguilar aerodrome, which had been occupied only days before. During the same sortie the Fiats flown by Carlos Bayo, Muntadas and de Hemricourt all received damage from ground fire.

Muntadas ended the war with 5 biplane victories.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	??/??/3?		1	Enemy aircraft	Destroyed	He 51
2	28/12/37		1	I-15 (a)	Destroyed	CR.32		Teruel	2-E-3
3	??/??/3?		1	Enemy aircraft	Destroyed	CR.32
4	??/??/3?		1	Enemy aircraft	Destroyed	CR.32
5	??/??/3?		1	Enemy aircraft	Destroyed	CR.32

Biplane victories: 5 destroyed.
TOTAL: 5 destroyed.
(a) Grupo 2-G-3 claimed 4 I-15s and 1 I-16 for the loss of 1 CR.32. The Republicans claimed 4 CR.32s while losing 1 I-15 and 2 damaged.

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
Spanish Republican Aces – Rafael A. Permuy López, 2012 Osprey Publishing, Oxford, ISBN 978-1-84908-668-4
Additional information kindly provided by Miguel Ansede Fernández, Alfredo Logoluso and Ondrej Repka.