Sardina served as a volunteer during the Spanish Civil War.

In the morning on 12 July, Bozidar Petrovich claimed a shared He 111 with Leonid Rybkin and Sardina in the Madrid area.

Sardina ended the war with 1 shared biplane victory. This one claimed in Spain.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
	12/07/37	morning	1/3	He 111	Shared destroyed	I-15		Madrid area	1a/Gr. 26

Biplane victories: 1 shared destroyed.
TOTAL: 1 shared destroyed.

Sources:
Air War over Spain - Jesus Salas Larrazabal, 1974 Ian Allan Ltd, Shepperton, Surrey, ISBN 0-7110-0521-4
Polikarpov I-15, I-16 and I-153 Aces - Mikhail Maslov, 2010 Osprey Publishing, Oxford, ISBN 978-1-84603-981-2
Additional information kindly provided by Alfredo Logoluso.