Trouble Executing Mission Using Line Scanner Camera

This is my first time using a Line Scanner (Push Broom) Camera with a pixhawk and QGC.
The scanner needs to be aligned with the flight direction for capturing data. I am uploading KML in the survey option. But when the flight takes place it does not takes 90 degree turns. Instead it goes left and then finishes the line moving backwards. Is there any option in which I can make sure that it is taking the right turns and the flight direction is aligned with the camera.
Any help is appreciated