26/01/2009

Looking for pure sky

Pure sky above haze
One of the pleasures I have while spending time in the cockpits is being dazzled.

At the cruising altitudes where commercial transport aircrafts cruise, the atmosphere is very pure and gives the sun the ability to shine really strongly.

The explanation is simple. The atmospheric layer close to the ground contains the vast majority of particles we find in the atmosphere: dust or various pollution. The layer in which these microscopic bodies are enclosed has a variable thickness depending on the weather conditions. When we are on the ground, we don't see that because no clear border is visible between atmospheric layers. But as soon as we pass over the lower layer, we realise that pure sky isn't so far from the surface of the earth. And in this place the sunlight is really strong (thus the sunglasses pilot style) and the blueness of the sky is really blue.

This day, the conditions were typically high-pressure, stable air mass on our continent. That is why the layer was pretty thin and thus the density of particles inside it was pretty high. I offered myself a cruise above the haze, where the sky is pure. Moreover, the atmosphere is very calm in this area (i.e. no turbulences at all). A lot of good reasons for the regular air traffic to take place there.

Flying back in Paris area, reality hits back: A Class at 1'500 feet. And be aware of the Falcon 900 flying just above this limit ...