Sitnikov was born in Grozny in 1920.

In May 1943, Serzhant Sitnikov served in the 71 IAP-KBF. During this time, the unit was equipped with Polikarpov I-153s.

Between 15:26-16:30 on 21 May 1943, a detachment of I-153s and I-16s from 71 IAP-KBF reconnoitred the Vaindlo-Tytärsaari direction, when two Me 109s and four Fw 190s approached in the vicinity of Lavansaari. During the combat, the number of the enemy rose to 8-12 aircraft. The I-153 pair of Starshiy Leytenant Gavrilov and Mladshiy Serzhant Nizhnik claimed one shared Bf 109 and the I-16 pair of Leytenant Viktor Parfynov and Mladshiy Serzhant Nikolai Bryuhanov another. Mladshiy Serzhant Sitnikov made an ’taran’ ramming attack on Bf 109 (a Fw 190 by another report) and managed to bale out safely.
A Finnish Messerschmitt section from 2/LeLv 34 took off from Utti at 14:35. The formation was led by luutnantti Veikko Evinen and the wingmen were kersantti Hemmo Leino and kersantti Mauno Kirjonen (MT-230) (Kirjonen had previously been shot down by a I-153 flown by Vladimir Shavrov on 22 July 1941).
The Finnish aircraft met a formation of Russian I-153s over Lavansaaari and Kirjonen reported:

"We engaged 7-8 enemy I-153 fighters at the height of 1000m NW of Lavansaari. I attacked head-on against two of the Russians. When I looked down, I saw a MT attack them from below. I made a turn and after this, I saw three machines go down. The MT had lost 2/3 of its right wing and one of the I-153s had lost both wings on the other side. The planes crashed near each other 5-8 km west from the northern tip of Lavansaari. The other I-153 crashed south of these two. I saw one pilot to land with his parachute and Evinen told me that it was a Russian one because the parachute was a square one."

Four days later, on 25 May, Sitnikov performed a second “taran” attacked when he rammed and destroyed another Bf 109 over Lavansaari Island but this time he wasn’t lucky and was killed when his fighter crashed.

Sitnikov was posthumously awarded the Order of the Red Banner.

Sitnikov ended the war with 2 biplane victories.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1943
1	21/05/43	15:28	1	Bf 109 (a)	Destroyed	I-153		Lavansaari	71 IAP-KBF
2	25/05/43		1	Bf 109 (b)	Destroyed	I-153		Lavansaari	71 IAP-KBF

Biplane victories: 2 destroyed.
TOTAL: 2 destroyed.
(a) Claimed in a “taran”-attack on Finnish Messerschmitt Bf 109G MT-228 (W.Nr 13890) of 2/LeLv 34. The pilot luutnantti T. Saalasti was killed.
(b) Claimed in a “taran”-attack.

Sources:
Aeroram
Kohtalokkaat lennot 1939-1944 - Jaakko Hyvönen kindly provided by Tuomo Lukkari
Red Stars 1 - Carl-Fredrik Geust, Kalevi Keskinen and Kari Stenman kindly provided by Ondrej Repka
Suomen Ilmavoimat part V – 1943 – Kalevi Keskinen and Kari Stenman, 2007, ISBN 978-952-99743-3-7
Suomen sodissa 1939-1945 menehtyneiden tiedosto
Additional information kindly provided by Christer Bergström and Ondrej Repka