The horizontal velocity of the airplane is,
[tex]v=135\text{ km/h}[/tex]The height of the airplane is,
[tex]h=1008\text{ m}[/tex]The vertical initial velocity of the box is zero as the airplane is moving in the horizontal direction.
let the time to reach the victim is t.
we can write,
[tex]\begin{gathered} h=\frac{1}{2}gt^2 \\ t=\sqrt[]{\frac{2h}{g}} \end{gathered}[/tex]Substituting the values we get,
[tex]\begin{gathered} t=\sqrt[]{\frac{2\times1008}{9.8}} \\ =14.3\text{ s} \end{gathered}[/tex]Hence the required time is 14.3 s