Transport Canada Commercial Helicopter Practice Exam

At night, it is most effective for a pilot to look off center at about 15 to 20 degrees. This technique aligns with the way human vision works in low-light conditions. Our eyes have two types of photoreceptor cells: rods and cones. Rods are more sensitive to light and are primarily responsible for night vision, but they are concentrated around the periphery of our retina rather than in the center. When a pilot looks slightly off-center, they are allowing the rod cells to pick up light from distant sources, which helps in detecting obstacles, terrain, and other aircraft in the night sky.

Looking directly into the landing light beam, while illuminating, can cause temporary blindness or reduced night vision due to the intense brightness overwhelming the eyes' adaptation to the dark. Focusing dead center can also limit awareness of surroundings, while wearing sunglasses after sunset is not practical and interferes with the eyes' natural adaption to low light. Thus, directing eyesight 15 to 20 degrees off center optimally enhances night vision and situational awareness for pilots.