Minnesota Flyer - Serving Midwest Aviation Since 1960

By Dan McDowell
MnDOT Aeronautics 

When night comes

 

C.M. Swanson

After a warm, bright, sunny day, the still, cool air of the evening sky and the rising moon call you to take flight.

For many, night flying is intimidating. Yet, to others, it is a challenge they willingly accept. Their reward is seeing the amazing beauty of villages and towns twinkling in the ocean of blackness below them and the moonlight shimmering on the lakes in a golden champagne color. Good night vision is a key to overcoming those challenges and enjoying night flight.

It is much easier to understand night vision and its associated challenges if, at first, you understand how the human eye works. Quite simply, there or millions of light sensitive nerves called rods and cones in the back of the eye. The rods and cones are in large part responsible for our ability to see.

The rods form a ring around the cones in the center of the eye, and can detect moving objects, shades of gray, and they give us peripheral vision. The cones are able to detect distant objects, detail, and color.

In normal daylight, the best way to see an object is to look directly at it. While at night, the best way to see an object is to look to the side of it. This will allow the rods to better detect the object, its movement (if any), and the subtle shades of reflected light. It is recommended to slowly scan an area to maximize your night vision.

When preparing for night flight, it is strongly suggested that you begin by adapting your eyes to the darkness. An example is; if you walk from the brightly lit terminal lobby to the darkened pilots lounge, it takes your eyes (cones) 5-10 minutes to adapt to the dimly lit room.

Once adjusted, the cones are now 100 times more sensitive to light. It takes nearly 30 minutes for the rods to fully adjust to the darkness, but once they do adjust, they become 100,000 times more sensitive to light. At many of today's well-lit airports it is nearly impossible to maintain complete darkness adaptation.

Bear in mind that exposure to bright lights will require you to repeat the complete darkness adaptation process. Here are some suggested ways to improve your night vision:

1. Do not wear sunglasses after sunset.

2. Do all you can to adapt your eyes to the darkness prior to flight.

3. Remember that it takes 30 minutes for your eyes to adjust once exposed to bright light.

4. Concentrate on seeing objects.

5. Move your eyes more slowly than you do in the daylight.

6. Force yourself to look off-center.

7. Adjust your cockpit lighting to optimal levels for viewing inside and outside the aircraft.

C.M. Swanson

At many of today's well-lit airports it is nearly impossible to maintain complete darkness adaptation.

8. Do not use yellow or pink highlighters on printed charts. Those colors do not show up at night if you use red cockpit lighting. If you use white cockpit lighting, you may see your highlighted lines but you sacrifice your adapted night vision.

It is vitally important that you carry a quality flashlight with a red night vision filter, and a fresh set of batteries. Though these days many, if not most flashlights, are very long life LED's. It is still suggested that you carry a similar spare flashlight with a spare set of fresh batteries.

Be sure these items are within easy and immediate reach. Should the need suddenly arise, there may not be time to search for them in the cockpit, and seeing through the darkness may not be possible for some time. Also, have your eyes checked regularly and always plan ahead for safe flying.

 

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