In August 1941, Starshiy Leytenant Trubitsin served in the 153 IAP, which operated in the Leningrad area. This unit was equipped with I-153s and I-16s.

In the morning on 20 August, kapteeni Toivo Halonen of LLv 44 bombed with seven Blenheims, vessels outside Puutsaari and loading facilities there. Both the supply warehouses and vessels received several hits. Russian fighters patrolling the area sent down Blenheim BL-117 at 07:40, since the escort of the Brewster swarm of 1/LLv 24 was insufficient. The crew of BL-117, consisting of pilot lentomestari Väinö Helanto, observer vänrikki Poju Merikallio and gunner korprali Eino Laitila were all KIA.
The Blenheim had been shot down by two I-153s flown by Starshiy Leytenant Trubitsin and Leytenant Tarasov of 153 IAP, which claimed an enemy bomber (identified as a Ju 88) over the Karelian Isthmus.

Trubitsin ended the war with 1 shared biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1941
	20/08/41	07:40	½	Blenheim	Shared destroyed	I-153		Puutsaari	153 IAP

Biplane victories: 1 shared destroyed.
TOTAL: 1 shared destroyed.
(a) Blenheim BL-117 of LLV 44 shot down and crew KIA.

Sources:
Suomen Ilmavoimat part III – 1941 – Kalevi Keskinen and Kari Stenman, 2007, ISBN 978-952-99743-1-3