However, he did not hold the post for very long, since he was arrested by the NKVD for allegedly endangering the life of Lavrenty Beria; on 13 August 1942, Gridnev and his crew were assigned to flying an escort flight for Beria's Li-2 transport plane, but by the time they were scheduled to take off from Krasnovodsk, a severe dust storm ensued, clouding visibility conditions.

Nevertheless, he was arrested by the NKVD, which claimed that he attempted to take off alone in the low visibility conditions to shoot down the Li-2 without witnesses to get revenge for Tukhachevsky.

Eventually, after prolonged violent interrogations and the support of other aviators who defended the decision to not take off in the dust storm in accordance with Stalin's orders, he was released in October, although few generals were willing to appoint him to a command role.

[1][4] Shortly after the end of the war he transferred to the 39th Guards Fighter Aviation Regiment in November, but was forced to retire from the military in August 1946 for health reasons.

After founding the Volgograd School of Young Cosmonauts in 1965 he headed the institution for over 20 years, supervising the graduation of over 1500 students, many of whom went on to hold careers in the military and aviation.