What indicates a change in landing minimums during equipment malfunction?

The correct answer is linked to the concept of full-scale deflection, which typically refers to the behavior of instruments that indicate a failure or malfunction in navigation equipment. When an aircraft experiences equipment malfunction, particularly in its navigational aids, a full-scale deflection on the instruments can indicate that the aircraft is no longer receiving accurate information necessary for landing. This can trigger a change in the required landing minimums because the reliability of the equipment has been compromised, meaning the pilot may need to adhere to more stringent criteria to ensure a safe landing.

In this context, maintaining safety becomes paramount, and pilots must rely on clearly established procedures regarding equipment status. Full-scale deflection signals that the equipment is either providing erroneous readings or is inoperative, necessitating that pilots switch to more conservative landing minimums until they verify the situation is back to normal.

The other options do not directly indicate when landing minimums should change due to equipment failure. Visual confirmations relate more to pilot observation than equipment operation, training requirements focus on preparation rather than real-time decision-making, and runway length is typically a fixed factor unrelated to malfunction scenarios.