A jet airplane flies with a speed of 1120 mph (mi/h) at an altitude of 2870 ft. It passes directly over my head. How soon after it passes directly

A jet airplane flies with a speed of 1120 mph (mi/h) at an altitude of 2870 ft. It passes directly over my head. How soon after it passes directly above me will I hear the sonic boom? The speed of sound is 343 m/s. (Caution: I am not asking how much time it took for the sound to travel from the airplane when it was directly overhead. The sonic boom originates from the airplane sometime before it reached the point directly overhead.)