Engineer Kochin's Error, (Russian: Ошибка инженера Кочина) is a 1939 Soviet thriller directed by Aleksandr Macheret.

[2][3][4][5] The film tells the story of how an aircraft engineer's decision to take classified blueprints home unravels a deadly web of espionage, betrayal, and intrigue in late 1930s Moscow.

An aircraft design engineer at an aviation plant, Kochin, makes the mistake of taking classified blueprints home to quickly revise them based on recent test results.

With the help of Kochin’s neighbor and romantic interest, Ksenia Lebedeva, Trivosh breaks into the engineer’s room and photographs the blueprints.

The transmission of the spy's encoded message, urging the urgent smuggling of the photographs abroad, occurs in a tailor's workshop, a meeting spot chosen by the agents.