What type of lights should be on when the engine is starting or running?

When the engine is starting or running, it is essential that the position lights are on. Position lights serve as a crucial part of an aircraft's lighting system, as they indicate the aircraft's orientation and enhance visibility to other pilots and ground crew during critical phases such as engine starts and taxiing.

Position lights are typically red on the left wing and green on the right wing, with a white light at the tail. This lighting configuration helps other aircraft and ground personnel to determine the aircraft's direction and in-flight status, enhancing situational awareness and safety.

While anti-collision lights, landing lights, and taxi lights might be used during various phases of flight or ground operations, position lights are the standard requirement for indicating the aircraft's position during engine operation to ensure compliance with aviation regulations and safety protocols.