Under what circumstance might a "go-around" be necessary during landing?

A go-around is a maneuver initiated by the pilot when a landing is deemed unsafe or not suitable due to specific circumstances. In this context, poor visibility conditions significantly hinder the pilot's ability to make a safe landing. If visibility is reduced, whether from weather conditions like fog, rain, or other obstacles, the pilot may not have a clear view of the runway or the surrounding environment, which complicates the landing process. This uncertainty poses potential risks, such as misjudging the approach or not being able to see other aircraft or hazards on the runway. Therefore, in such situations, executing a go-around allows the pilot to climb back to a safe altitude and reassess for another landing attempt when conditions may improve or become clearer.

The other scenarios outlined may not present immediate reasons for a go-around. For instance, if another aircraft lands before yours, it could still be safe and appropriate to land as long as the landing is correctly timed and the runway is clear. Equipment malfunctions during landing warrant a go-around only if they significantly threaten the landing process. Lastly, if the runway is clear, there typically wouldn't be a reason to go around, as the safety of the approach would usually be confirmed.