How do you determine the flight path angle?

To determine the flight path angle, one must utilize trigonometric ratios that relate to the vertical and horizontal distances traveled by the aircraft. The flight path angle is essentially the angle of ascent or descent of the aircraft relative to the horizontal plane, which can be visualized using a right triangle.

In this context, the vertical component represents the change in altitude (height) of the flight, while the horizontal component represents the distance covered along the ground. By applying trigonometric functions, such as sine, cosine, or tangent, the angle can be calculated based on the ratios of these two distances. This geometric relationship is fundamental in aviation because it allows for the assessment of the aircraft's climb or descent performance relative to the trajectory it is following.

Simply relying on distances above the ground, the speed of the aircraft, or its weight does not provide a direct method for determining the flight path angle and does not incorporate the necessary geometric relationships involved in a flight's ascent or descent trajectory. Thus, using trigonometric ratios is the appropriate and precise method for calculating the flight path angle.