Viktor Kustov was born in Moscow on 26 April 1909.

He joined the Red Army in 1932 and in December 1935, he graduated from the 7th Stalingrad Military Aviation School.

After graduating, he was posted to 12 IAE, 111 IAB in the Leningrad Military District.

Leitenant Kustov volunteered for service in the Spanish Civil War, departing on 20 August 1937 and arrived on 28 August, flying from France.

In Spain, he served in 1^a/26 flying Polikarpov I-15s.

On 14 October, kapitan Yevgeniy Antonov, 1^a/26 (I-15), claimed two shared CR.32s while leitenant Kustov claimed one shared. These claims were made ”in group”.

On 4 December, he was wounded in air combat and hospitalised for two months.

Kustov returned home on 25 February 1938. This was earlier than planned but due to his wounds.
In Spain, he had claimed 3 shared victories and flown combat missions for 80 hours.

In 1938-1939, he commanded a Zvena in 38 IAP and then in 44 IAP.

Kapitan Kustov was posted as a Zvena CO in the 22 IAP (I-16) to take part in the Nomonhan Incident.
On 29 May 1939, the Soviet Air Force sent a group of well-merited pilots from the Central Aerodrome Frunze in Moscow aboard three Douglas DC-3s to Mongolia (a second group was sent to Mongolia by train). Before they left, they all had paid a visit to marshal Voroshylov, Commissar of Defence, and komkor A. Laktionov, Commander of the VVS.
The group consisted of 48 airmen, both fighter and bomber pilots and technical staff. Among the fighter pilots were Sergey Gritsevets, Ivan Lakeyev, Kustov, Grigoriy Kravchenko, Nikolay Gerasimov, Leonid Orlov, Yevgeniy Stepanov, A. Nikolayev, Viktor Rakhov. Eleven of the pilots had been decorated with the Gold Star of the Hero of the Soviet Union.
Komkor Yakov Shmushkevich, who after arriving in Mongolia became the commander of the whole Soviet-Mongolian Air Force/Aviation Group, commanded the group. The group had been created immediately after the big defeat of the Soviet air regiments on 27-28 May.
The leading pilot in the DC-3s was Aleksandr Golovanov (future Air Marshal of VVS during the Great Patriotic War and commander of the Long-Range Soviet Bombers). The other two pilots were Gratsov and Niuhtinow.
The group took off after midday and the trip lasted for three days before finally landing in Czita (near the border of Mongolia in the Transbaikalyan Military District and approximately 650km from the conflict).
At Czita they collected their aircraft and flew on to Tamsag Bulag, which was the main Soviet Air Base and which was situated approximately 120km east of the Khalkhin Gol.
The newly arrived pilots were distributed among the eskadrilyas of the 70 IAP (100 SAB) and 22 IAP (23 SAB). Major Sergey Gritsevets was posted to 70 IAP of the 100 SAB (Mixed Air Brigade) (150 BAP was also part of 100 SAB) as an advisor in tactical matters to major V. Zabaluyev, commander of the 70 IAP.

Late in July, Kustov became eskadrilya CO in 56 IAP (I-16).

On 25 July, major Stepan Danilov from 56 IAP (I-16) claimed a shared Ki-27 together with another pilot north of Khamardaba in the afternoon. The second pilot was possibly leitenant Kustov, since it’s known that he claimed a Ki-27 together with a second pilot during the day.
Starshiy leitenant Petr Il’ich Afanasyev (born 1913) was shot down and killed in his I-16 in the Khamardaba area around 14:00.

On 3 August, kapitan Kustov claimed a Japanese bomber (reported as a ”SB-96” over Khamardaba Mountains by a ”taran” ramming attack but was killed while doing so.
This was possible a Ki-30 (s/n 118) from 10th Sentai, which was reportedly shot down by enemy fighters at roughly 4 km south-west from Height 742. The crew was KIA; pilot Staff Sergeant Yoshio Matsuzaki and gunner Staff Sergeant Fukuyoshi Uchida.
At the time of his death, Kustov had flown around 100 combat missions in the Incident.

On 29 August 1939, Kustov was decorated with a posthumous Gold Star of the Hero of the Soviet Union and the Order of Lenin.

At the time of his death, Kustov was credited with 3 shared biplane victories and a total of 1.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
	14/10/37		1/?	CR.32	Shared destroyed	I-15		Spain	1a/26
	22/12/37		1/?	Bf 109	Shared destroyed	I-15		Spain	1a/26
	22/12/37		1/?	Bf 109	Shared destroyed	I-15		Spain	1a/26
	1939
	25/07/39	14:00 ca	1/2	Ki-27	Shared destroyed	I-16		Khamardaba	56 IAP
1	03/08/39		1	SB-96 (a)	Destroyed	I-16		Khamardaba	56 IAP

Biplane victories: 3 shared destroyed.
TOTAL: 1 and 4 shared destroyed.
(a) Claimed in a ”taran” ramming attack. Possibly Ki-30 (s/n 118) from 10th Sentai, which was shot down by enemy fighters (crew KIA).

Sources:
All aces of Stalin 1936-1953 – Mikhail Bykov, 2014
Soviet Aces 1936-1953
Soviet airmen in the Spanish civil war 1936-1939 - Paul Whelan, 2014 Schiffer Publishing Ltd, ISBN 978-0-7643-0
Soviet Fighter Pilots 1936-1953 - Mikhail Bykov