Looking for pure sky

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 ...

Flying over remote areas

One of the air transportation's problems concerns the flights above remote areas, like deserts or oceans. These areas can be extremely vast and it is impossible to land there in case of a flight interruption because no appropriate airport can be found.

In the beginning, routes were made so that aircrafts wouldn't fly more than 60 minutes (considering the one engine out cruise speed) away from a suitable airport. This was a safe solution but implied pretty inefficient routes, which were very far from direct.

A first solution was integrated in aircrafts themselves, and some were equipped with three or four jet engines. For these airplanes, the loss of one engine became a less important problem and more direct routes could be used. But the 60 minutes rule still applied to 2-engines aircrafts, still unable to take economical routes.

Today, technological improvements allowed the aviation industry to reach excellent reliability and performance: engines break down with very small probability and 2-engine planes can fly almost normally with one engine out. Thanks to that, interesting routes can be used, thus allowing huge benefits in flight time, burnt fuel and of course CO2 rejected in the atmosphere.
This special use of twin-engine aircrafts is ruled by the ETOPS (Extended-range Twin-engine Operation Performance Standards) standards. An ETOPS approbation works for one air carrier for a given aircraft type equipped with a give type of engine. This way, the conception of aircraft and engines, their maintenance and the tracking realised by the airline are certified to fly further than the 60 minutes limitation.

For instance, Air France's Boeing 777 and their General Electrics GE90 engines use the ETOPS 180 approbation, allowing them to fly up to 180 minutes away (at the one engine out speed) from an airport where a suitable landing can be performed.
This standard allows the airline to use direct routes between France and Asia, flying over Siberia as it was the case when I took this picture.



For a private pilot flying a one engine aircraft, the ETOPS concept doesn't exist: in case of an engine failure we just have to choose a field.

Paris - Hong-Kong, 10h50.


->More details in the Wikipedia article concerning ETOPS standards

Digiatl trip

Here is a short video from a Toussus -> Pont-sur-Yonne -> Toussus flight. You'll see some castles, some colourful Yonne river meanders, the city of Fontainebleau and its famous forest and finally the Ferté Alais airfield with vintage aircrafts of the Amicale Jean-Baptiste Salis.

Factor 10

Three years ago precisely, I was passenger of a Boeing 777 between Paris CDG and New-York JFK airport. Around 20 minutes after take-off we reached the European continent's border, ready to cross the Northern Atlantic area to join the United States. 30'000 feet and some cumulus clouds below us we could see a special mount that receives around three million visitors each year. It is the beautiful Mont-Saint-Michel, and I used my camera to get this shot.

This summer, two Cessna 172 hours after leaving Paris to reach Morlaix instead of the United States, the Mont-Saint-Michel was once again on my way. Here is a shot of this superb area, taken 3'000 feet above ground, which means ten times lower than previously.

A few days later I went there to visit the mount, by foot this time.

It's hard to admit, but some places are even more beautiful when seen from the ground.

-> More details about the Mont-Saint-Michel on Wikipedia

One Zero Zero

That's it! Two years and nine months after my first flying lesson I crossed the line, the one that makes the total flight time a three digits counter.

For this special step I realized a navigation through the Sologne (a French region) followed by some sightseeing above some world famous castles of the Loire Valley such as Chenonceau, Amboise and Chambord. Combined with a drink stop at Amboise airfield, all this made an excellent travelling afternoon I won't forget!

It's said that the first 100 hours of flight time are the toughest to get. I will check that...

Toussus - Amboise - Epernon - Toussus, 3h18.

Passenger's perceptions

Passenger [noun] A traveler on a public or private conveyance other than the driver, pilot or crew.

Adapted to air transportation, the passenger's role is to my opinion one of the best occupation we can find. Admiring clouds, cities or fields for hours with a false feeling of slowness and forgetting we are 30'000 feet above ground at a speed that is not that far from the speed of sound. That is a pleasant activity!

As a passenger, reality is so far away that the movement is hardly perceptible. The static window giving us a sensation of immobility, the world seems to be moving behind it. These few laminated glass layers are finally much more than a classical window...

This day, relaxed and having an infinite blue as wallpaper, I almost forgot there were a complete crew of pilots and flight attendants working in this Qantas Boeing 767. There are ingrate jobs!

Melbourne - Sydney, 1h05.

Flying around the runways

A well known basic training exercise for student pilots is flying in the aerodrome traffic pattern, or aerodrome circuit. Without surprise, it consists in realizing a complete circuit around the aerodrome runways.

The goal is making one take-off and one landing separated by four 90 degrees turns in the same direction if possible, so that you finish your circuit where you started it. Not only this exercise is a complete and intense flying training, but also it teaches the student a standard method allowing him to integrate in any aerodrome circuit, positioning himself correctly so that he can land the airplane easily.

On this picture five consecutive aerodrome circuits are shown, and they are far from perfect. The aerodrome circuit has indeed, behind its apparent simplicity, a special esthetic criteria: its rectangularity. The difficulty is in making precise 90 degrees turns, and making them each time at the exact same point. That is not always easy, once factors like the wind or other airplanes flying around you are taken into consideration.

While we are making our noisy turns, people living beneath us are becoming irritated. Sorry !

Over the clouds, the sun always shines

To my eyes, one of the most attracting aspects of an air transport pilot's life is its unlimited sunshine feature!

It must be really pleasant knowing that today at work you'll pass over this low winter cloud layer to join natural light in its purest state.

Yes, this is also a reason why I am fighting against the ATPL (Air Transport Pilot License) and its 14 papers. One day, I'll be able to get rid of those 8 octas of sky covered by condensed water droplets, which preferred hobby consists in ruining our winter without hesitation.

Another solution would be to exile myself to the Atacama Desert in Chile. With yearly precipitations under 1 millimeter I think fog would become a less important matter!

Behind an aeroplane

Do aircrafts draw large straight lines on our skies so they can better be spotted?

Yes, but it isn't the only reason. In fact these condensation trails are simply composed of very small condensed water droplets frozen by the very low ambient temperatures present at high altitudes: -45°C (-49°F) at 30'000 feet in the atmosphere considered as standard (definition of the International Standard Atmosphere). The fuel is made of hydrogen and carbon atoms. During the combustion process occurring with oxygen inside the jet engine's combustion chamber, water molecules are produced. It's the same principle for mopeds and farm tractors! But with different quantities involved and slightly different atmospheric conditions, straight lines are created and can sometimes live a complete day.

On this picture we see another phenomenon, which is less common and disappears pretty quickly. The trail coming from the top left hand corner contains not only the classical engine caused contrail, but also two materialized vortexes. They are made of rolling air and they are due to a side effect of the lift force produced by our beautiful aircrafts, allowing them to fly. By the way, everybody would be much happier if these vortexes could be avoided! 

These atmospheric trails are responsible for multiple theories and they are also a curious paradox as they contribute at the same time but via two different effects, to the planet surface heating and cooling.

That being said, the more contrails I see, the better I feel!

More details:

Wikipedia - Contrails

The jet engine's complexity

Why is it so complicated to become an air transport pilot?

A glance to the right side gives us some clues.

That complex thing is an aircraft's jet engine. Unfortunately, before being able to use one, we must have fully understood its principles of working. This implies looking in details at some technical points. And between the pneumatic, electrical, fuel or hydraulic circuits the ATPL (Air Transport Pilot License, the public transportation pilot's traffic code) is a really well stocked course. Especially for the "Aircraft General Knowledge" part.

A jet engine simply accelerates some air in order to produce a force that will push our aircraft really fast, allowing it to do its aircraft job: flying. However, it inflicts a cycle of operations to the ingested air that are not easy to understand, at all. On the menu we find some compression, combustion, adiabatic expansion and some theorems named after great scientists to explain all of this.

That is why the piston engine, propeller-driven aircraft suits me totally. It is easy to use and the working principle is just a bit more complex than for a moped.

But let's face it; I won't cross the Atlantic with a moped. This justifies the ATPL!

More details:

Wikipedia - Jet engine

Flight to Dieppe

What would this yellow line be?

It's the result of a sudden need to see the ocean. That is why I went on a plane navigation to Dieppe (in the North-West West of France) to admire Etretat cliffs from above, this impressive limit where land simply stops.

With a very modest airplane, the ocean is one hour away from Paris. However this GPS trace of my Toussus-le-Noble <-> Dieppe trip shows my tendency not to fly straight. I did what I could, the wind was blowing pretty strongly from the Southwest today, but it wasn't rough so I won't blame it.

One day, I'll fly a modern plane telling me where the wind precisely comes from and with which intensity. This day, the yellow line will be straight.

Toussus-le-Noble - Dieppe - Toussus-le-Noble, 2h28.