When beginning an approach, what is controlling?

In aviation, when beginning an approach, both ceiling and visibility are critical factors in determining the safety and feasibility of landing. The ceiling refers to the height of the cloud base above the ground, which affects whether a pilot can safely conduct their approach within visual flight rules (VFR) or must switch to instrument flight rules (IFR). Visibility, on the other hand, indicates how far a pilot can see horizontally, which is essential for identifying the runway and surrounding terrain during landing.

In a safe approach, it is crucial that both of these elements are taken into account to ensure that the aircraft can land safely without encountering low clouds or reduced visibility that could lead to spatial disorientation or loss of situational awareness. If either the ceiling or visibility is below the required minimums, it may necessitate a missed approach or diversion to an alternate airport. Thus, controlling both ceiling and visibility means ensuring that both parameters meet safety standards for a successful landing.