Helicoptorial

Chuck Meager here. It has been one day, 13 hours and 26 minutes since my last flight. It was at night, just after midnight, the moon was near full on a clear night. As I was flying along, I kept saying to myself, 'This has got to be the greatest thing on earth! Then a strange thought entered my head, if I put as much energy into something that would make me money, as I do with flying, I'd be rich beyond belief. But the thought quickly passes as I become immersed in the night, destined to be a slave to my pleasure. It was a safe and successful flight that night, everything going according to plan. I remember it hasn't always been that way... There was a time when flying at night was very scary. But through the all powerful equation E = T + DL (Experience= Training + Dumb Luck), I have learned to truly enjoy flying at night.

The uncertainty of flying at night can be frightening. For most of us, the cause of this fear is our degraded vision. Vision is something we pilots cherish. Without good vision we'd be just like everyone else. AACK! ! Can't have that. It would bruise our precious egos. I know that the first time you get a Class 1 Flight Physical for the military, you had better have 20/20 vision. In our aeromedical studies we learned that night vision is equivalent to 20/200. That's legally blind! (Imagine the flight surgeon issuing a pilot certificate to someone with 20/200 vision.) If it wasn't so dangerous it would be comical to have all these blind people flying around the unsuspecting population below.

So here we are blind at night and yet we're out there conducting business in our aircraft. Did we bump are heads or what?? But still we do it all the time and there aren't that many accidents at night. Why?

Training and past experiences. By past experiences, I'm talking about how you've been doing things in the dark all your lives. (For some of us, that could be metaphorically true as well.) I remember playing basketball on the playground until I could barely see the basket. Or walking into a dark room. You might slow down if you're not sure where things are. Or here's a good one ...remember the game where you reached into a hole in a closed box and tried to feel the objects to choose the right one without seeing the object?

The kind of skills we learned as children help us function in the aircraft. Playing in the dark, we unconsciously practice scanning techniques and reacting to moving and stationary objects. Or walking into a dark room, we learned, by stubbing our toes a few times, to slow down or wait until our eyes adapt to the lower light level. We also learned that different objects feel different. So we know what the fuel switch feels like without having to look.

But what we learned as children won't help us in every situation. This is because flying can be a little more stressful than playing basketball at night. Stress adds a new dimension. Or maybe I should say that the added dimension in flying adds stress. We have to retain our brains to think in three dimensions and create reactions accordingly. So we need to know how the eye works, how we estimate distance and depth, and what types of visual illusions we can experience. By being familiar with these things, we can better apply them to any situation. If you're just doing things in the aircraft without some reason other than 'my instructor told me to', you're no better than the computer you're sitting in front of right now. Each situation is different and knowing the reasons that we do things will allow you to be more adaptable.

Through our aviation training, we learned about the night blind spot. The absence of rods in the fovea makes it necessary to use off-center vision so we can see things better under conditions of low illumination. And that it takes 30 - 45 minutes for our eyes to completely adapt to the dark. We also learned that scanning will keep us more alert to our situation and prevent us from getting fixated.

Visual illusions, vestibular illusions, and distance estimation and depth perception, are the things that can affect us easiest when flying at night. Knowing what to do to prevent or recover from the illusions or how to view things to maintain your orientaion, is extremely important.

So... here's the scenario. You're flying along at night, away from the city lights, and you see what appears to be an aircraft coming toward you. You change course to avoid him but you're still not quite sure on his position. Your having a difficult time estimating his distance and course. -OR- You're flying over the city at night, talking with approach control, from nowhere you see the familiar green and red lights of another aircraft rapidly closing in on you -OR- You're looking at the city lights and you think you see one moving - is it a car? is it an aircraft? is it a threat?

What do you call the illusion where you feel like you're going backwards but in reality it's your reference point moving forward?

Or how about the illusion that makes you want to climb over the tower or power lines when you know you have enough altitude to clear the obstacle?

What do you call the technique for estimating distance where the closer an object is to you the faster it appears to be traveling?

Or the technique for estimating distance of the aircraft near the airport?

Knowing all the names for these is pretty trivial unless you want to talk coherently about them to an evaluator. What's really important is how you use them. As you're flying in the dark, pay attention to your instruments. You don't want to be too fast during an approach. Scan around and note your rate of closure. Look at your VSI and note your rate of descent. Remember that the helicopter flies the same at night as it does in the day. However you should be more cautious in the dark. That will give you more time to react to the things you can't see. Don't relax your scan just because you're talking with approach control. They're people and they make mistakes too. And of course, probably the most important for a successful flight at night is planning.

Well, it's getting late. I'm going to be doing what most people should be doing at night - going to sleep and dreaming about flying helicopters. Talk amongst yourselves for next month's topic: Night Vision Devices: Don't leave home without them.

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