Monthly Archives: January 2019

Why Sunsets Are So Colorful From The Air

Many thanks to Boldmethod for sharing…  Source: Boldmethod

primaryGolfCharlie232

Seeing a sunset or sunrise from the cockpit is a view you’ll never forget. Here’s why they’re so stunning and full of color.

First, A Quick Review Of Sunlight

Sunlight, or visible light, can be thought of as a wave and a part of the electromagnetic spectrum. When the spectrum is split up, you see all the colors as a rainbow.  Each visible color has a different wavelength along the spectrum. Blue light has the shortest wavelength at 300 nanometers. Red light has the longest at 700 nanometers. As visible light passes through the Earth’s atmosphere, small particles in the air can scatter shorter wavelengths more efficiently, like what you see on the left side of the diagram below.

During the day, blue light is the primary wavelength that’s scattered in the atmosphere, and only a portion of the blue light is scattered. But when the sun is low in the sky during sunrise or sunset, all of that changes.

blue scatter small

“Scattering” Causes Colorful Sunsets

According to Steve Ackerman, a Meteorologist at the University of Wisconsin, Madison, “because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky. More atmosphere means more molecules to scatter the violet and blue light away from your eyes. If the path is long enough, all of the blue and violet light scatters out of your line of sight. The other colors continue on their way to your eyes. This is why sunsets are often yellow, orange, and red.”

Wing SunsetBoldmethod

Red has the longest wavelength of any visible light, which is why the sun may appear red when setting directly on the horizon. The light has passed through the most atmosphere possible before reaching your eyes.

1GolfCharlie232

Why Are Some Sunsets More Colorful Than Others?

According to National Geographic, you may see more vibrant sunsets based on the seasons. In the east, fall and winter create incredible sunsets because the air tends to be dryer and cleaner for the path of sunlight.  Pollution tends to mute and muddy the colors of sunsets because large particles in the lower atmosphere tend to have that effect. And in general, places with a lot of haze have less dramatic sunsets.

2Wikimedia

Why Sunsets Look So Great From The Air

When you’re flying through layers during climb or descent, you’ll find the best sunsets where the sun is clearly visible between multiple layers of clouds.  When sunlight is sandwiched between cloud layers, it bounces off the clouds, further intensifying the sunset. That’s why sunsets often times seem more spectacular from the air. On top of that, cloud layers can create dramatic shadows on the ground, or on other cloud layers.

3Swayne Martin

Where have you seen the best sunsets or sunrises? Tell us in the comments below.

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5 Rules of Thumb Every Pilot Should Know  Boldmethod — Peter “Just Loves Flying”

5 Rules of Thumb Every Pilot Should Know  Colin Cutler

1) Estimating Your Crosswind Component

When you’re on the ground, it’s easy to use the crosswind chart in your POH, or an E6B. But when you’re in the air, neither of those options are very practical.

Lucky of all of us, there’s an easier way. If the wind is 30 degrees off the runway, your crosswind component is about 50% of the wind speed.

If the wind is 45 degrees off the runway, the crosswind component is about 75% of the wind speed.

And if the wind is 60 degrees or more off the runway, the crosswind component is roughly the same as the total wind.

crosswind component

2) 10% Weight Increase = 20% Takeoff and Landing Distance Increase

The more weight you have, the more runway you need. And while this rule is far from exact, it gets you in the ball park for a normally aspirated plane.

Obviously, when it comes time to calculate your actual performance, you’ll want to pull out your POH.

distance weight

3) Takeoff roll increases about 10% for every additional 1,000 feet of density altitude

For most normally-aspirated airplanes, you add about 10% of takeoff roll distance for every 1,000′ of density altitude (DA).

For example, in Denver, with an increase of 3,200′ of density altitude, you’d increase your takeoff roll by about 32%.

So if you have a 1,500′ takeoff roll on a standard day in Denver (3 degrees C), you’ll increase that roll to almost 2,000′ on a 30C day.

Denver-Takeoff

4) When Should You Start Your Descent?

3 degrees is a comfortable descent rate in just about any aircraft. But when you’re approaching an airport, how do you know when to start down?

Divide the altitude you need to lose by 300.

For example, if you’re at 11,000′, and you need to get down to a pattern altitude of 2,000′, you need to descend 9,000′.

9,000/300 = 30 miles.

If you start a 3-degree descent 30 miles out, you’ll hit pattern altitude as you reach the airport. Keep in mind, you’ll want to add a few miles on to your number, so you hit pattern altitude slightly before you get to the airport.

1-degree-descent

5) ILS Course Width

VFR pilots can make good use of the ILS too. Whether it’s a dark moonless night, or a long straight-in on a hazy day, following the ILS to your runway keeps you safe from terrain and obstructions (not to mention, you know you’re lined up with the right runway).

The closer you get to the runway, the more sensitive the signal is. As you cross the threshold, 1/2 dot deflection on the localizer = about 1/2 the runway width. So if you’re a half dot off as you approach the runway, you’re going to be looking at the runway edge lights.

ils-loc

What are other rules-of-thumb do you use? Tell us in the comments below.

Categories: Flying, Gambia, Microlights, Uncategorized | Tags: , , , , | 1 Comment

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