Archive for the 'Regulations' Category
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).
The freedoms of the air
The freedoms of the air are a set of rights signed between countries, which grants the right to overfly an airspace and/or to land in those countries (bilateral treaties). There are 9 different freedoms, depending on the kind of flight. All these rules were defined in 1944 during the International Civil Aviation Convention in Chicago.
The right or privilege, in respect of scheduled international air services,…
1st.- …granted by one State to another State or States to fly across its territory without landing.
2nd.- …granted by one State to another State or States to land in its territory for non-traffic purposes
3rd.- …granted by one State to another State to put down, in the territory of the first State, traffic coming from the home State of the carrier
4th.- …granted by one State to another State to take on, in the territory of the first State, traffic destined for the home State of the carrier
5th.- …granted by one State to another State to put down and to take on, in the territory of the first State, traffic coming from or destined to a third State
6th.- …via the home State of the carrier, traffic moving between two other States
7th.- …granted by one State to another State, of transporting traffic between the territory of the granting State and any third State with no requirement to include on such operation any point in the territory of the recipient State
8th.- …of transporting cabotage traffic between two points in the territory of the granting State on a service which originates or terminates in the home country of the foreign carrier or (in connection with the so-called Seventh Freedom of the Air) outside the territory of the granting State (consecutive cabotage)
9th.- …of transporting cabotage traffic of the granting State on a service performed entirely within the territory of the granting State (stand alone cabotage)
Freedoms of the air
North Atlantic Routes: I eat beef, you eat fish
Every single day, hundreds of commercial airplanes cross the north atlantic, flying transcontinental routes linking North America and Europe basically, the NAT (North Atlantic Tracks). The performances of these flights are much different and complex due to its distant routes from any kind of airport.
The twin-engine aircrafts operating these flights (usually big ones) must have the ETOPS rating, explained in other post. That is because the nearest alternative airport when flying above the atlantic is 180 minutes far. If an engine failure happens (or any other system), this aircraft should divert to the closest airport immediately.
Another huge problem is the radar coverage. As a matter of fact, this radar coverage does not exist. Radars must be set up on ground or close (not floating over the sea). The main Air Traffic Control facilities (Shanwick Oceanic for European side and Gander Oceanic for US side) are equipped with air traffic management systems that by means of pilot manual position reports, they have some sort of “radar-like” screen with all the airplanes’ positions.
The third and big problem as well (but solved anyway) is about communications. The communicacions between pilots and controllers use VHF (Very High Frequency from 30 MHz to 300MHz) frequency range. VHF waves only reach “line-of-sight” spaces. So, in that case they must use HF (High Frequency from 3 MHz to 30MHz) that bounces off the ionosphere and give coverage to greater distances. Nevertheless, even this advantage, sound quality is much poor.
The NAT routes are designed and published daily. They are defined with an entry waypoint, an exit waypoint and between, waypoints are defined with coordinates (there are no navaids to define them). Early in the morning, westbound routes are published. Then late at night, eastbound routes are published. Europe incoming routes are usually defined at higher latitude, to take advantage of the Jet Stream (high speed wind, will post about this).
By the way, pilots flying these routes cannot eat the same meal. 
Here we can appreciate North Atlantic Routes all the day long
ETOPS: Unlimited Trustworthiness
The ETOPS (Extended-range Twin-engine Operational Performance Standards) defines the twin-engine aircrafts requirements to operate flights where the nearest enroute alternative airfield is further than 60 minutes.
At the beginning of commercial aviation, because of the lack of regulations concerning alternative airfields further than 60 minutes, the air carriers started putting pressure on Aviation Administrations to be modified, in order to be able to operate transatlantic routes with twin-engine. Because of that, ICAO and the FAA drawn up a new reguation that allowed to operate those routes.
Nowadays, there are several ETOPS ratings depending on some parameters. These parameters are including the engines and systems’ reliability, crew training and ratings, manteinance and so on.
Author Andrés Meneses
These are the different ETOPS ratings issued these days by Aeronautical Authorities:
- ETOPS-75
- ETOPS-90
- ETOPS-120/138 (138 minuts is a 15% plus 120 minuts, in order to cover a little part of the Atlantic Ocean, not covered with ETOPS-120)
- ETOPS-180/207
An ETOPS rating is gradual. That means if you want to reach ETOPS-120 rating, first of all the aircraft must have reached the ETOPS-75 rating (with 200 sectors with 98% relieability), then the ETOPS-90 rating (with 300 sectors with 98% reliability), and finally the ETOPS-120. For example, in order to achieve ETOPS-120 rating, the airplane must prove less than 0.05 per mil in-flight shut-down. That means, flying 20.000 flights there’s only one in-flight shut-down (obviously, an airplane does not achieve 20.000 routes in its life).
There’s a tremendous application called Great Circle Mapper where you can compute each ETOPS rating maximum range around the earth.