In April 1942 Tkachenko served in the Northern Fleet (2 GIAP/VVS-SF) flying Polikarpov I-153s.

On 30 April 1942, he shot down Ju 87 WNr. 5884 of I/StG 5 in the Kestengi area.
The German crew managed to return to the German side.

He claimed a Bf 109 over Luostari on 12 April 1944, while flying an P-39.

Tkachenko ended the war with 1 biplane victory and a total of 2.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1942
1	30/04/42		1	Ju 87	Destroyed	I-153		Kestengi area	2 GIAP-SF
	1944
2	12/04/44		1	Bf 109	Destroyed	P-39		Luostari	2 GIAP-SF

Biplane victories: 1 destroyed.
TOTAL: 2 destroyed.
(a) Ju 87 WNr. 5884 of I/StG 5 shot down.

Sources:
Information kindly provided by Ondrej Repka.