Final answer:
To compensate for the crosswind on the crosswind leg of a rectangular course, the pilot must adjust the airplane's heading using vector analysis to maintain the intended path over ground.
Step-by-step explanation:
When flying the crosswind leg of a rectangular course, the airplane must be correctly oriented to account for the crosswind to maintain the intended ground track. In the scenario where a pilot is flying due north, but a wind is blowing out of the northeast at 90 km/h, the pilot must adjust the heading of the airplane to compensate for the wind drift. If the plane can fly at 300 km/h in still air, the pilot needs to use vector analysis to determine the correct heading angle and the ground speed of the aircraft.
An important strategy in this navigation problem is to graph the vectors representing the plane's airspeed, the wind's velocity, and the resultant ground speed. By constructing a vector diagram, the pilot can determine both the angle at which the plane must be pointed relative to the air mass and the effective speed over ground. Last-minute maneuvers may include aligning the plane with the runway direction just before landing, ensuring a safe touch down with the wheels pointing straight down the runway.