Which of the following is NOT a valid condition for performing a go-around?

A go-around is a vital maneuver used by pilots when certain conditions during an approach indicate that a landing cannot be safely completed. The correct answer highlights a specific condition that is not considered valid for deciding to execute a go-around.

In aviation, approach speed is crucial for maintaining control of the aircraft during landing. If the approach speed decreases significantly, it could lead to an unstable approach, but this alone does not automatically mandate a go-around unless accompanied by other warning signs or parameters. The key idea is that a slow speed must be assessed alongside the overall approach profile and other conditions.

In contrast, the other conditions presented are indeed valid reasons for a go-around. If the glide slope indicator is more than one dot off, it signals that the aircraft is not on the correct path for a safe landing, prompting the need for a go-around. Additionally, if the altitude exceeds 1,000 feet during the approach after the decision point, that typically means the approach is not proceeding as planned, again warranting a go-around. Lastly, if the vertical speed exceeds 500 feet per minute during the final approach phase, it often indicates too rapid a descent, which compromises safety and may require a go-around.

Therefore, the context surrounding these critical flying parameters