How is the secondary bulb activated if one wing tip navigation light bulb fails?

The navigation light system is designed with safety and reliability in mind, ensuring that if one wing tip navigation light bulb fails, the aircraft can maintain visibility. When a bulb failure occurs, the system automatically activates the secondary bulb in the same navigation light assembly. This automatic switching feature is crucial as it allows for continuous operation of the navigation lights without pilot intervention, which is essential during critical flight phases such as takeoff and approach.

The automatic activation of the secondary bulb contributes to the overall redundancy built into aircraft systems, ensuring that pilots can consistently comply with visibility regulations and enhance safety. In contrast, the other options—such as manual switches, resetting circuit breakers, or using backup switches—require active input or intervention from the flight crew, which may not always be practical or timely in flight scenarios. This automation of the navigation light system is fundamental to reducing pilot workload and increasing operational safety.