Which of the following is NOT a reason to go missed?

The reasoning behind choosing landing gear malfunction as the answer is based on the contexts in which a missed approach is typically executed. A missed approach is generally called when conditions affecting the aircraft’s ability to land safely arise during the approach phase.

Lost visual reference, unstable approach, and sudden changes in weather conditions are all interpreted as critical issues that can directly compromise the safety of the landing. For example, losing visual reference can prevent the pilot from accurately aligning with the runway. An unstable approach may indicate that the aircraft is not configured correctly for landing, posing risks to safety. Lastly, sudden changes in weather can drastically reduce visibility or create hazardous conditions at the airport, necessitating a missed approach to ensure a safe landing attempt later.

In contrast, a landing gear malfunction, while serious, generally occurs at a later stage of the flight and would typically not be classified under the immediate reasons for going missed during the approach phase. A pilot would usually engage with the issue of landing gear malfunction while still safely airborne, often opting to land or troubleshoot rather than executing a missed approach. Thus, landing gear malfunction is not aligned with the context of reasons to go missed, making it the appropriate choice as the answer to the question.