When is it necessary to issue supplementary information during landing instructions?

Issuing supplementary information during landing instructions is essential when weather conditions are unfavorable. This is because adverse weather (such as low visibility, strong winds, or heavy precipitation) can significantly affect an aircraft's approach and landing. By providing additional information, air traffic controllers help pilots make informed decisions regarding their approach and landing sequence to enhance safety and ensure smooth operations.

In situations where conditions are poor, supplementary information might include details about wind conditions, runway conditions, or alternative landing options. This extra guidance is crucial for pilots to adjust their approach accordingly, enhancing their situational awareness and ensuring a safe landing.

On the other hand, while other options mention various scenarios, they do not necessitate the same level of supplemental instructions. For instance, successful landings and visibility above VFR minimums typically imply safer conditions where pilots may not need extra information. Similarly, when no other traffic is present, the focus shifts to the individual landing aircraft rather than requiring supplementary data for safety.