30/09/2008

Choosing a field after an engine failure

Field for an emergency landingWhen flying with a single engine aeroplane, we have to be prepared to the engine failure situation. In this case, the solution is an off field landing, which means gliding to a field without power.

It could look like obvious but the ideal field choice is in fact a discipline included in the flying skills.
The problem is: there are many fields but even if the failed engine aircraft keeps on flying, the available reaction time is very short (3 minutes between engine loss and landing is a lot) and some obstacles are very hard to detect from above, like power lines.
The pictured field would be a perfect choice for an off field landing: flat, large, short grass, small furrows, no power line or fence in the vicinity, not far from a village,...

Unfortunately it has a very low probability of being elected as best off field landing place. It is indeed located just aside Merville airport in the North of France, and even with a failed engine, a runway remains the best place to land an airplane.

I would need to have more than one engine on my aircraft to become less concerned by fields ... later I hope!

28/09/2008

Over the clouds, the sun always shines

Flying under the sunlight over the cloudsTo 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!

25/09/2008

The unstable Cumulus Mediocris

Cumulus Mediocris cloudWe are never far from clouds when flying and with time I'm starting to really appreciate them. These large heaps of condensed water droplets are indeed excellent visual indicators for the atmosphere's mood, this so vast but so changing playground.

The Cumulus is a multiple faces cloud. It can either indicate very nice weather in its Humilis state, or horrible flying conditions known as storms in the Cumulonimbus version.
The specimen shown on this picture is a Cumulus Mediocris. It means that the cloud shows vertical development characteristics, thus its cauliflower aspect on the top. The situation is indeed mediocre because depending on how ambitious the cloud is and on the available resources in heat and humidity, it may transform into a Congestus to then become a gigantic Cumulonimbus at the apex of its short career.

But today, the fog lets us stuck on the ground, no Cumulonimbus risk then!

Behind an aeroplane

Contrails behind aeroplanes
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:

24/09/2008

The jet engine's complexity

An aircraft's jet engineWhy 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:

23/09/2008

The small plane's oil hatch

Cessna 152 oil hatchThe small hatch hidden on the top of the engine hood gives access to this pretty yellow cap used to probe the engine oil's quantity.

In a car, the oil level remains a boring needle living on the dashboard.

When preparing for a flight, we like to be convinced that our engine is in its best mood. It would allow, amongst other, to reduce the probability of an unwanted country landing. Thus it is mandatory to check that enough oil is put at the engine's moving pieces disposal so that it can be correctly lubricated and cooled down. Where fuel would be to the engine what food is to our body, oil would be its water, allowing it to work normally. And we'd rather be correctly hydrated.

Then, when the remaining quantity becomes too close to the preflight checklist's limit, it's better spending 5 minutes and getting dirty than hurting the engine's feelings!

Cap locked, hatch locked. Preflight checklist can go on.

22/09/2008

Time considerations

Flying between cloud layers
This picture shows more than a sunset. It somehow figures the differences of limits between a private and a line pilot.

The private pilot can generally only fly by day and he considers that once the night has arrived, he can go to sleep.
A line pilot has a different point of view. In our case, he left Paris after sunset, but the shortest way on earth to join New-York City (heading slightly to the North and then head South-West) allows us to catch extra rays of light in the shape of what would be a rising sunset.
A few thousand feet lower, ships crossing the Atlantic Ocean have already litten their candles, but we can still enjoy some last sunrays before lighting ours.

Unfortunately, the race is already lost. The sun always wins and once arrived at JFK airport, it will be night again.

Paris - New-York, 8h10 and two sunsets.

Flight to Dieppe

Tracé de l'enregistrement GPS de ma navigation vers DieppeWhat 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.