A depraved sicko nearly plunged to his death from a fourth-floor window after sexually attacking a young woman in her Queens apartment building, police sources said yesterday.

Gustavo Avila, 20, was listed in critical condition at Elmhurst Hospital following Wednesday’s incident on 83rd Street in Jackson Heights, sources said.

Avila allegedly accosted the 21-year-old woman as she entered the lobby of her building.