The aircraft's anti-collision lights must be on when the engine is running unless doing so would cause vertigo or a hazardous condition.

• A. Anti collision lights when engine on unless causing vertigo or hazardous condition
• B. Anti collision lights only during night
• C. Anti collision lights never required
• D. Anti collision lights only during takeoff

Answer: (A)

Anti-collision lights exist to make your airplane highly visible to other pilots and people on the ground, reducing the chance of collisions. The rule requires these lights to be on anytime the engine is running, unless turning them on would cause vertigo or create a hazardous condition. This is why the best choice states that the lights must be on when the engine is running, with the single exception for vertigo or a hazardous situation. The other options miss the requirement by narrowing it to night only, claiming they’re never required, or restricting usage to takeoff only.