When following behind a large airplane to land, what is the safest action?

When landing behind a large airplane, the safest action is to touch down beyond where the large aircraft landed. This is important because large aircraft generate significant wake turbulence, which can pose a serious hazard to smaller airplanes. The vortices created by the wings of a large aircraft tend to sink and drift downward, potentially causing loss of control if a smaller aircraft encounters them during landing.

By targeting a touchdown point that is beyond where the large aircraft has landed, you ensure that you are avoiding the areas where the wake turbulence is most likely to be present. This strategy provides a safe buffer zone, allowing you to land without the risk of encountering the hazardous effects of the wake.

The other options may not effectively mitigate the risks associated with wake turbulence. For example, landing as soon as possible could place you directly in the wake turbulence. Descending immediately after a large aircraft could lead to encountering its vortices if you are not sufficiently spaced and aligned. Maintaining a constant altitude could also result in flying into the wake turbulence zone, particularly if you fail to adjust your approach based on the previous aircraft's landing location. Thus, aiming to touch down further along the runway is the most prudent approach in this scenario.