Virgin America will release an in-flight wireless Internet on all his flights by the second quarter of 2009. In fact, they flew a test flight from San Francisco to test the whole system and it kinda works.

This gadget, called GoGo, will not forbid any special content, but there will be some constraints though ( no Skype, no IP voice systems,…). The company’s philosophy is not to edit the content that passengers want to watch, but to offer WiFi in order to let the people choose what to watch. This system will be available above 1000 feet and it works with 3G technology.

Thence, get connected in the airplane will be $10 on short flights, and $13 on longer legs. You just need a laptop to get access. Virgin says that later in 2009 they will include an integrated in-flight entertainment system, that will give connectivity to people who don’t have laptops or PDA’s.

Of course, nowadays, a lot of airlines are willing to incorporate this devices to their birds.

Source: Original Link

Each conventional aircraft, just because they have wings, they create wake turbulences at wing tips. Since we have high pressure underneath the wing and low pressure above it, this pressure difference converge at the wing tips. Air from high pressure goes up to low pressure zones, plus the forward movement of the airplane create an espiral-like movement of rough air behind the airplane. These wake turbulences are increased (abruptness and size) when dealing with heavy airplanes and low speeds, like the approach stage.

Wake turbulence created by the airplane (NASA)

This rough air does not concern this aircraft, but the aircraft behind it does. Actually, the aircraft behind might fly through this turbulence. As the air is in rotation, it does not keep sticked to the wing foil, so it may cause a lift loss. That’s why ICAO establishes a minimum separation between aircrafts, enroute as well as in approach, in order to avoid rough air. These turbulences drive away because of air viscosity and because of the wind. Even that, they could be 5 miles long and go down up to 900 ft.

In order to decrease these effects, there is a very used and useful tool called winglet, set up at the wing tip, and it slows down the air flow reducing then, the wake turbulence (and the fuel consumption).

Winglet                        Source: Air Guide Online

The ACAP document is published by each aircraft manufacturer and it is used in airport design, not only for maneuvering area but also for terminal buildings. In addition, this document enables an optimization of all the airplane services around the gate.

In order to make a more pleasant explanation, we will use the Boeing 747-400 ACAP as an example. We will see the main parts of the the file, 6 important parts:

1.- AIRPLANE DESCRIPTION: Describes the dimensions of the aircraft, the exterior ones (size, gap between gear, the clearance between wing tips and ground, etc…) and the interior ones (load zone, cabin, cockpit, seat configuration, etc…). It also describes the operational weights like MTOW, MZFW or MLW for each model and engines set.

B747-400 door layout with all distances from the airplane’s head, in order to build proper jetways.

2.- PERFORMANCE: It’s made up with several sorts of charts, explaining the aircraft performances (that concerns airport designing). The two main charts are the payload vs. range chart and the take-off distance vs. weight. The first one, connects the maximum range as a function of the payload. The second chart, connects the aircraft wheight with the take off distance in different conditions. 

Take off distance vs. take off weight chart.

3.- GROUND MANEUVERING: It points out the parameters that are really necesary to move the airplane on ground. There, you can find ground-turns radius, cockpit visibility and different paths when steering.

Front gear path (red line) and main gear path (blue line) when 135º turn.

4.- TERMINAL SERVICING: It classifies the aircraft assistance on terminal (handling service). The ACAP gives you information about turn-around times for each service (fueling, cleaning, catering), ground services procedures and energy sources that is needed.

Sockets and control panels for ground servicing.

5.- JET ENGINE WAKE AND NOISE DATA: Explains the noise and jet wake factors with charts. The main usefulness is to avoid certain major accidents that may occur with these two sources. 

Jet engine speed diagram for take off thrust.

6.- PAVEMENT DATA: It details the forces exerted to the pavement. That determines what kind of pavement in use where an airplane can taxi all over (concrete, tarmac, etc…). Usually all these data is refered to gear pressure or gear tracks.

At the end of each ACAP, the aircraft manufaturer announces upcoming models, and aircraft draws as well.

The ACAP documents are typically public. Nevertheless, Airbus ACAPs are not public. But Boeing’s are. You can download them and take a look at Boeing Website.

Please, if you do not understand something or you just have questions, feel free to contact via comments. Don’t be afraid, it’s not that easy sometimes.