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 ...

My cumulus neighbour

Flying over cumulus clouds
One of the impassable borders of the private pilot is the cloud layer present during a flight.

Flying through clouds most of the time means that you put yourself in a situation where both visual flight basic references (ground and horizon) are unavailable. That is when you leave the Visual Flight Rules (VFR) for the Instrument Flight Rules (IFR). For this in Europe, we must hold a Commercial Pilot License together with an Instrument Rating, and we must be regularly trained in respect with the European rules.

To make it short, flying through clouds is unreachable for a private pilot. Except when the clouds are clement towards our small aircrafts, like they were on this picture. In this situation, the thin broken clouds allowed me to keep a visual on the ground and on the horizon even above them.
During this flight back from Deauville, the upper limit of the layer stood at approximately 3'500 feet and I gave myself the opportunity to watch the clouds from above, but I remained modest and only flew 1'000 above them.

It's so nice watching the sunny side of these aerial sheep. Just another good reason for flying !


Toussus - Deauville - Toussus, 2h49.