Why might engineers choose a specific number of cones for approach lights?

Engineers might choose a specific number of cones for approach lights primarily for optimal navigation guidance. The configuration and number of cones are critical in ensuring that pilots can clearly see and interpret the lights during approach, which directly impacts safety and effectiveness during landing procedures. Having the correct number of cones helps to provide precise visual cues that assist pilots in determining their position relative to the runway, especially in conditions where visibility may be compromised. The design is not just about visual appeal or cost efficiency; it is fundamentally about enhancing the navigational aids that support safe aircraft operations.