In May 1943, Starshiy Leytenant Gavrilov served in the 71 IAP-KBF. During this time, the unit was equipped with Polikarpov I-16s and 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 Anatoliy 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."

Gavrilov ended the war with 1 shared biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1943
1	21/05/43	15:26-16:30	1	Bf 109 (a)	Shared destroyed	I-153		Lavansaari	71 IAP-KBF

Biplane victories: 1 shared destroyed.
TOTAL: 1 shared destroyed.
(a) Claimed in combat with Bf 109s from 2/LeLv 34, which claimed two I-153s for the loss of one Bf 109 in a ‘taran’ attack. 71 IAP-KBF claimed three Bf 109s (including one in a ‘taran’ attack) while the aircraft making the ‘taran’ attack.

Sources:
Aeroram
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