Designing an airport runway
One of the key elements of an airport is the runway. In fact, if there is no runway, there is no airport anyway. The runway is the place where airplanes take off or touch down. Then, the runway features will be an important issue to bear in mind.
First of all we have the runway orientation. The runway direction will be a major fact in terms of airport operations. A wind intensity and direction research must be done in order to obtain and gather wind data, and then determine the most likely wind direction in that area. Now let’s talk about physical characteristics.
The two more important sizes are the runway length and the width. Depending on the aircraft expected to operate on that airport, you might use larger or shorter distances. There is no specific runway length established by FAA or ICAO, but could change from 200 meters to infinite (if we could have that region). About the runway width it is mandatory to be greater than 18 meters up to 60 meters (able to land an A380). There are other physical matters, like strips up to 150 meters (around the runway) and shoulders up to 15 meters (paved margins at both sides of the runway).
In addition, to promote the most rapid drainage of the water, there should be a transverse slope not greater than 2%. Longitudinal slopes cannot be greater than 2% (just imagine a 3000 meters runway, 2% would mean 60 meters of vertical variation).
ACAP: Airplane Characteristics for Airport Planning
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.