Most recent edit on 2007-11-13 19:04:45 by MikeBevington
Deletions:
orcatroceltc
Edited on 2007-11-09 22:05:25 by DaracMondo
Additions:
orcatroceltc
Edited on 2007-01-30 20:19:40 by MikeBevington
Additions:
RENAMED, see: 316 - AirWays - (Flight Levels, and Directions of Flight) by LluisdelCerro
Deletions:
by Llu?s del Cerro
On land, persons and vehicles normally use the roads to move between two points. Both roads and highways are built on the ground, physically visible and we move around following them.
Most aircraft move across the air following paths called airways in a similar way as cars move on the highways. These airways, however, are invisible and depicted in the enroute charts by means of navaids and intersections. These navaids are, basically, VORs and NDBs, while intersections are normally points defined by distances and radials to navaids or geographical co-ordinates.
Many official aeronautical administrations have public web sites where all real charts can be obtained for free. You may find most of them in the VATSIM Chart Center. Also, from the EUROCONTROL∞ web site you can access the EAD site and obtain ALL the charts for all the European Union states and other not belonging to the EU as well.
Some countries (like France) include all information in the enroute charts while others (like Spain or Germany) only display the directions of flight for the airways. Nevertheless, the flight levels can be found in other documents providing even more detailed information. For those charts where all data are depicted, we must look at the legend to find out the abbreviation used for the even and odd flight levels.
The enroute charts themselves are coded and grouped under ENR-6 section, normally for lower and upper airspace separatedly. The documents containing the information on the levels of flight are coded and grouped under ENR-3 - ATS ROUTES section and the airways are listed there in alphabetical order. Thus, in those cases where the flight level is not depicted in the charts, the first thing we should do is find out the basic designator (see next paragraph) and then search for it alphabetically in the ENR-3 documents.
Airways may cross a continent completely and have portions or segments of variable length which run between navaids or intersections. Each airway has a name or code (also known as BASIC DESIGNATOR) formed by a letter and a number between 1 and 999. The basic designator may have a prefix, U, for example, to indicate that it belongs to the upper airspace, and an additional letter, F, for example, to indicate that it is an airway where only flight information service is provided, for example UG600F.
Within a FIR/UIR, the border between upper and lower airspace is normally at FL245. Thus, lower airspace is below FL245 until land or sea level (AGL/MSL) whilst the upper airspace is above FL245 until UNL (unlimited). Within Flight Information Regions (FIR) we would find the so-called Control Areas including, among others, the terminal areas (TMA) and airways (AWY).
For the purpose of this article, an airway may exist in the lower airspace, upper airspace, or both. The lower limit of an airway (in lower airspace) is given in the Aeronautical Information Publications (AIP). For an airway in the upper airspace, the upper limit would be FL460, which is usually the limit of controlled airspace. There may be airways in both airspaces with the same route, but their respective basic designators will be different depending on the airspace where they run through.
An airway may be single or double direction of flight (along all its length or part of it), which means that an airway may be flown in one direction (only west to east, for example) or in both. In the enroute charts it is depicted whether an airway has single or double direction of flight, as in case of single direction we may see an arrowhead pointing the correct direction of flight, whilst the double direction airways do not display any arrowhead.
Lets deal now with the flight levels of the airways:
Normally, all airways have a MEA (Minimum Enroute Altitude), which is the minimum allowed level to fly that airway ensuring clearance over obstacles and radio reception which is determined by the MRA (Minimum Reception Altitude). The MRA warrants that the navaids will be received at least 500 below the MEA. The altitude of the MEA is normally depicted in charts in a different color (usually blue) and is placed beside some segments of the airway.
Also, and for Europe, we can see "E" and "O" or ?A? and ?B? to show the levels of flight, and the symbols ">" and "<" which are used to display the directions of flight. According to this, ?E? or ?B? stands for EVEN flight levels (for example: FL240, FL260, FL280, FL300, FL320, etc.), whilst "O" or ?A? stands for ODD flight levels (for example: FL250, FL270, FL290, FL310, FL330, etc.). The symbols ?<? and ?>? are usually depicted beside the ?E? or ?O? and are used to indicate whether that segment of the airway must be flown on even or odd flight levels in the direction pointed by the symbol.
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction (which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
Levels below FL290:
- Course 360 to 179: F190, FL210, etc.
- Course 180 to 359: FL180, FL200, etc.
Levels above FL290:
- Course 360 to 179: FL290, FL330, etc.
- Course 180 to 359: FL310, FL350, etc.
Flight Level Conversion Chart∞ to be used ONLY when no enroute charts available
Directional Airways
Although we are talking about airway segments, only a few of them change their flight level along its path. Thus, for a certain airway, we will normally fly the same flight level during all its length (even or odd). Also, normally, when an airway ends and starts a new one, the latter uses the same levels of flight as the former one.
Let?s see an example:
We are now going to prepare a flight plan from LFPO (Paris Orly) to LEBL (Barcelona El Prat). The route is the following:
PIROG UN855 VASON UR106 LCA UN860 SUVAN GUERE UZ365 BELPA UQ131 GAI UN859 ROCAN PUMAL
PIROG is the SID (Standard Instrumental Departure) waypoint where we will join the first airway (UN855) of our route. PIROG is about 50 nm southeast of LFPO.
If we have a look at the chart, we will see that at this point the airway UN855 has an arrowhead pointing southward. The number ?33? should be found somewhere in the first segment between PIROG and ARNON meaning that this is the distance between these two intersections. We may also find an ?O? or an ?A? and the symbol ?>? pointing south meaning that this part of the airway must be flown in odd flight levels in the direction shown by the symbol ?>?, thus southwards.
Our next waypoint is VASON and depicted in the chart with a black triangle. This symbol means that this is a ?mandatory reporting point? where the pilot should report to the ATC when over flying it. When we reach this intersection we will change the airway, leaving the UN855 to join the UR106. As you will see, this is a short airway, single direction southwards and for odd flight levels.
At LCS VOR we leave UR106 to join the UN860 which has the same restrictions as the former: single direction southward and odd flight levels.
Our flight plan includes SUVAN intersection which is a mandatory reporting point. The same is applicable to GUERE.
At GUERE we join the UZ365 also depicted as for odd flight levels southward by means of the symbols ?O>? or ?A>?, depending on the chart editor. We will continue on the UZ365 until BELPA where we join the UQ131. This airway has an arrowhead pointing south and an ?O>? or ?A>?. According to this, the UQ131 does only accept traffic southward and flying odd flight levels.
The next waypoint in our route is GAI VOR where we leave UQ131 to join UN859. As before, the arrowhead and the symbols are telling us the way to fly that part of this airway: southward and odd flight levels.
We have almost reached the end of our journey at ROCAN, the last mandatory reporting point between Marseille (LFMM) and Barcelona (LECB) FIRs. Normally, shortly before reaching this point we will be transferred (handoff) between LFMM_CTR and LECB_CTR, being the latter facility, which will issue the appropriate STAR (Standard Terminal Arrival Route) via PUMAL to our destination, as this is the last fix we have in our flight plan route and a valid STAR.
At PUMAL we leave the airway to start the sandard instrumental arrival procedure which will end with a safe landing on the active runway at Barcelona (LEBL).
This has been an example on the right way to fly a flight plan route using airways and following correctly the directions and flight levels for each airway.
When should we apply the semi-circular rule when filling the ?flight level? box of our flight plan? This rule should only be used when neither the pilot or the ATC have enroute chars to find out which is the right flight level. This rule may also be used when flying between islands (like in the Canaries) where distances are too short as to join any airway. In any case, we should always keep in mind that the semi-circular rule is a secondary way of choosing the flight level. Thus, do not be surprised if once you have requested a cruise level according to this rule, the ATC on duty amends it according to the flight levels of our filed airways.
For those willing to see a different example we will now have a quick look to the route between LEBL (Barcelona El Prat) and LGAV (Athens Venizelos):
The charts for this flight show that most of it will be on the airway UM601. This airway comes from the north Atlantic ocean, runs to the southeast crossing the Iberic peninsula and has double direction of flight. If we have a look at the chart, we will see that it must be flown on even flight levels from BLV vor to the northwest and also even flight levels from BLV to Barcelona (south-eastwards). Thus, this airway changes its levels of flight at BLV VOR.
From Barcelona towards the east it must be flown on even flight levels until ALG VOR (in Sardinia island) where we should change to an odd flight level as long as we continue flying UM601 eastward according to the indications depicted in the charts.
As we can see, the UM601 is a good example of an airway using double direction and changing levels of flight depending on the segment.
Final note:
When I control, sometimes I find pilots asking me why I change their flight levels and whether this is a particular case for Spain. Normally what happens is that those pilots still do not know what is an airway and that the European airspace is a single one for all European countries since 2004.
VATSIM is putting a great effort in the Pilot Resource Centre (http://www.vatsim.net/prc∞) and it is a wise decision, even for experienced simmers, to regularly have a look in it and learn or refresh our knowledge.
Acknowledgements:
Thanks to all VATSIM members which actively participate in discussions of subjects like this in the mail list of the Spanish vACC. I am specially indebted to Francisco Urqu?a and Pepe Morales, real ATCs, for their comments, contributions and suggestions, and also to Joaquin Blanco for providing me with the information regarding the enroute charts for U.S.A. and Canada.
I hope that this article will be useful to make more realistic our simulation experience and keep always in mind that the best we perform our role in VATSIM skies, the more the others will enjoy our company.
Edited on 2007-01-30 00:35:40 by LluisdelCerro
Additions:
Many official aeronautical administrations have public web sites where all real charts can be obtained for free. You may find most of them in the VATSIM Chart Center. Also, from the EUROCONTROL∞ web site you can access the EAD site and obtain ALL the charts for all the European Union states and other not belonging to the EU as well.
Some countries (like France) include all information in the enroute charts while others (like Spain or Germany) only display the directions of flight for the airways. Nevertheless, the flight levels can be found in other documents providing even more detailed information. For those charts where all data are depicted, we must look at the legend to find out the abbreviation used for the even and odd flight levels.
The enroute charts themselves are coded and grouped under ENR-6 section, normally for lower and upper airspace separatedly. The documents containing the information on the levels of flight are coded and grouped under ENR-3 - ATS ROUTES section and the airways are listed there in alphabetical order. Thus, in those cases where the flight level is not depicted in the charts, the first thing we should do is find out the basic designator (see next paragraph) and then search for it alphabetically in the ENR-3 documents.
Deletions:
Many official aeronautical administrations have public web sites where all real charts can be obtained for free. You may find most of them in the VATSIM Chart Center. Also, EUROCONTROL
EUROCONTROL∞
Edited on 2007-01-30 00:22:16 by LluisdelCerro
Additions:
Many official aeronautical administrations have public web sites where all real charts can be obtained for free. You may find most of them in the VATSIM Chart Center. Also, EUROCONTROL
EUROCONTROL∞
Edited on 2007-01-30 00:07:34 by LluisdelCerro
Additions:
Flight Level Conversion Chart∞ to be used ONLY when no enroute charts available
Deletions:
Flight Level Conversion Chart∞
Edited on 2007-01-30 00:06:16 by LluisdelCerro
Additions:
On land, persons and vehicles normally use the roads to move between two points. Both roads and highways are built on the ground, physically visible and we move around following them.
For the purpose of this article, an airway may exist in the lower airspace, upper airspace, or both. The lower limit of an airway (in lower airspace) is given in the Aeronautical Information Publications (AIP). For an airway in the upper airspace, the upper limit would be FL460, which is usually the limit of controlled airspace. There may be airways in both airspaces with the same route, but their respective basic designators will be different depending on the airspace where they run through.
Normally, all airways have a MEA (Minimum Enroute Altitude), which is the minimum allowed level to fly that airway ensuring clearance over obstacles and radio reception which is determined by the MRA (Minimum Reception Altitude). The MRA warrants that the navaids will be received at least 500 below the MEA. The altitude of the MEA is normally depicted in charts in a different color (usually blue) and is placed beside some segments of the airway.
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction (which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
From Barcelona towards the east it must be flown on even flight levels until ALG VOR (in Sardinia island) where we should change to an odd flight level as long as we continue flying UM601 eastward according to the indications depicted in the charts.
Deletions:
On land, persons and vehicles normally use the roads to move between two points. Both roads and highways are built on the ground, physically visible and we move around fol-lowing them.
For the purpose of this article, an airway may exist in the lower airspace, upper airspace, or both. The lower limit of an airway (in lower airspace) is given in the Aeronautical In-formation Publications (AIP). For an airway in the upper airspace, the upper limit would be FL460, which is usually the limit of controlled airspace. There may be airways in both airspaces with the same route, but their respective basic designators will be different depending on the airspace where they run through.
Normally, all airways have a MEA (Minimum Enroute Altitude), which is the minimum allowed level to fly that airway ensuring clearance over obstacles and radio reception which is determined by the MRA (Minimum Reception Altitude). The MRA warrants that the navaids will be received at least 500 below the MEA. The altitude of the MEA is nor-mally depicted in charts in a different color (usually blue) and is placed beside some segments of the airway.
Use the DAFIF enroute charts available at http://www.vatsim.net/prc∞ under VATSIM Chart Centre and answer YES to any requirement. In these charts, the odd flight levels are expressed by an ?A? and the even by a ?B?.
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction(which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
From Barcelona towards the east it must be flown on even flight levels until ALG VOR (in Sardinia island) where we should change to an odd flight level as long as we continue flying UM601 eastward.
I wait for you somewhere at Barcelona (LECB) FIR in VATSIM, of course.
Edited on 2006-12-23 15:06:22 by MikeBevington
Additions:
Flight Level Conversion Chart∞
Edited on 2006-12-03 10:36:51 by MikeBevington
Additions:
Final note:
Acknowledgements:
Deletions:
Final note:
Acknowledgements:
Edited on 2006-12-03 10:35:58 by MikeBevington
Additions:
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction(which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
Directional Airways
Deletions:
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction(which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
Edited on 2006-12-03 10:32:21 by MikeBevington
Additions:
~-Course 360 to 179: F190, FL210, etc.
- Course 180 to 359: FL180, FL200, etc.
- Course 360 to 179: FL290, FL330, etc.
- Course 180 to 359: FL310, FL350, etc.
Deletions:
~-Course 360 to 179: F190, FL210, etc.
~-Course 180 to 359: FL180, FL200, etc.
~-Course 360 to 179: FL290, FL330, etc.
~-Course 180 to 359: FL310, FL350, etc.
Edited on 2006-12-03 10:31:48 by MikeBevington
Additions:
Levels below FL290:
~-Course 360 to 179: F190, FL210, etc.
~-Course 180 to 359: FL180, FL200, etc.
Levels above FL290:
~-Course 360 to 179: FL290, FL330, etc.
~-Course 180 to 359: FL310, FL350, etc.
Deletions:
Levels below FL290:
Course 360 to 179: F190, FL210, etc.
Course 180 to 359: FL180, FL200, etc.
Levels above FL290:
Course 360 to 179: FL290, FL330, etc.
Course 180 to 359: FL310, FL350, etc.
Oldest known version of this page was edited on 2006-12-03 10:25:41 by MikeBevington []
Page view:
How High to Fly - AIRWAYS
Flight Levels and Directions of Flight
by Llu?s del Cerro
On land, persons and vehicles normally use the roads to move between two points. Both roads and highways are built on the ground, physically visible and we move around fol-lowing them.
Most aircraft move across the air following paths called airways in a similar way as cars move on the highways. These airways, however, are invisible and depicted in the enroute charts by means of navaids and intersections. These navaids are, basically, VORs and NDBs, while intersections are normally points defined by distances and radials to navaids or geographical co-ordinates.
Airways may cross a continent completely and have portions or segments of variable length which run between navaids or intersections. Each airway has a name or code (also known as BASIC DESIGNATOR) formed by a letter and a number between 1 and 999. The basic designator may have a prefix, U, for example, to indicate that it belongs to the upper airspace, and an additional letter, F, for example, to indicate that it is an airway where only flight information service is provided, for example UG600F.
Within a FIR/UIR, the border between upper and lower airspace is normally at FL245. Thus, lower airspace is below FL245 until land or sea level (AGL/MSL) whilst the upper airspace is above FL245 until UNL (unlimited). Within Flight Information Regions (FIR) we would find the so-called Control Areas including, among others, the terminal areas (TMA) and airways (AWY).
For the purpose of this article, an airway may exist in the lower airspace, upper airspace, or both. The lower limit of an airway (in lower airspace) is given in the Aeronautical In-formation Publications (AIP). For an airway in the upper airspace, the upper limit would be FL460, which is usually the limit of controlled airspace. There may be airways in both airspaces with the same route, but their respective basic designators will be different depending on the airspace where they run through.
An airway may be single or double direction of flight (along all its length or part of it), which means that an airway may be flown in one direction (only west to east, for example) or in both. In the enroute charts it is depicted whether an airway has single or double direction of flight, as in case of single direction we may see an arrowhead pointing the correct direction of flight, whilst the double direction airways do not display any arrowhead.
Lets deal now with the flight levels of the airways:
Normally, all airways have a MEA (Minimum Enroute Altitude), which is the minimum allowed level to fly that airway ensuring clearance over obstacles and radio reception which is determined by the MRA (Minimum Reception Altitude). The MRA warrants that the navaids will be received at least 500 below the MEA. The altitude of the MEA is nor-mally depicted in charts in a different color (usually blue) and is placed beside some segments of the airway.
Also, and for Europe, we can see "E" and "O" or ?A? and ?B? to show the levels of flight, and the symbols ">" and "<" which are used to display the directions of flight. According to this, ?E? or ?B? stands for EVEN flight levels (for example: FL240, FL260, FL280, FL300, FL320, etc.), whilst "O" or ?A? stands for ODD flight levels (for example: FL250, FL270, FL290, FL310, FL330, etc.). The symbols ?<? and ?>? are usually depicted beside the ?E? or ?O? and are used to indicate whether that segment of the airway must be flown on even or odd flight levels in the direction pointed by the symbol.
Use the DAFIF enroute charts available at
http://www.vatsim.net/prc∞ under VATSIM Chart Centre and answer YES to any requirement. In these charts, the odd flight levels are expressed by an ?A? and the even by a ?B?.
The situation is different in the U.S.A. and Canada where the charts depict an arrowhead when an airway is for a single direction or without the arrowhead if it has a double direction(which is normally the case). Similarly, the flight levels in the USA and Canada are assigned in the upper airspace (above FL180) in the following way:
Levels below FL290:
Course 360 to 179: F190, FL210, etc.
Course 180 to 359: FL180, FL200, etc.
Levels above FL290:
Course 360 to 179: FL290, FL330, etc.
Course 180 to 359: FL310, FL350, etc.
Although we are talking about airway segments, only a few of them change their flight level along its path. Thus, for a certain airway, we will normally fly the same flight level during all its length (even or odd). Also, normally, when an airway ends and starts a new one, the latter uses the same levels of flight as the former one.
Let?s see an example:
We are now going to prepare a flight plan from LFPO (Paris Orly) to LEBL (Barcelona El Prat). The route is the following:
PIROG UN855 VASON UR106 LCA UN860 SUVAN GUERE UZ365 BELPA UQ131 GAI UN859 ROCAN PUMAL
PIROG is the SID (Standard Instrumental Departure) waypoint where we will join the first airway (UN855) of our route. PIROG is about 50 nm southeast of LFPO.
If we have a look at the chart, we will see that at this point the airway UN855 has an arrowhead pointing southward. The number ?33? should be found somewhere in the first segment between PIROG and ARNON meaning that this is the distance between these two intersections. We may also find an ?O? or an ?A? and the symbol ?>? pointing south meaning that this part of the airway must be flown in odd flight levels in the direction shown by the symbol ?>?, thus southwards.
Our next waypoint is VASON and depicted in the chart with a black triangle. This symbol means that this is a ?mandatory reporting point? where the pilot should report to the ATC when over flying it. When we reach this intersection we will change the airway, leaving the UN855 to join the UR106. As you will see, this is a short airway, single direction southwards and for odd flight levels.
At LCS VOR we leave UR106 to join the UN860 which has the same restrictions as the former: single direction southward and odd flight levels.
Our flight plan includes SUVAN intersection which is a mandatory reporting point. The same is applicable to GUERE.
At GUERE we join the UZ365 also depicted as for odd flight levels southward by means of the symbols ?O>? or ?A>?, depending on the chart editor. We will continue on the UZ365 until BELPA where we join the UQ131. This airway has an arrowhead pointing south and an ?O>? or ?A>?. According to this, the UQ131 does only accept traffic southward and flying odd flight levels.
The next waypoint in our route is GAI VOR where we leave UQ131 to join UN859. As before, the arrowhead and the symbols are telling us the way to fly that part of this airway: southward and odd flight levels.
We have almost reached the end of our journey at ROCAN, the last mandatory reporting point between Marseille (LFMM) and Barcelona (LECB) FIRs. Normally, shortly before reaching this point we will be transferred (handoff) between LFMM_CTR and LECB_CTR, being the latter facility, which will issue the appropriate STAR (Standard Terminal Arrival Route) via PUMAL to our destination, as this is the last fix we have in our flight plan route and a valid STAR.
At PUMAL we leave the airway to start the sandard instrumental arrival procedure which will end with a safe landing on the active runway at Barcelona (LEBL).
This has been an example on the right way to fly a flight plan route using airways and following correctly the directions and flight levels for each airway.
When should we apply the semi-circular rule when filling the ?flight level? box of our flight plan? This rule should only be used when neither the pilot or the ATC have enroute chars to find out which is the right flight level. This rule may also be used when flying between islands (like in the Canaries) where distances are too short as to join any airway. In any case, we should always keep in mind that the semi-circular rule is a secondary way of choosing the flight level. Thus, do not be surprised if once you have requested a cruise level according to this rule, the ATC on duty amends it according to the flight levels of our filed airways.
For those willing to see a different example we will now have a quick look to the route between LEBL (Barcelona El Prat) and LGAV (Athens Venizelos):
The charts for this flight show that most of it will be on the airway UM601. This airway comes from the north Atlantic ocean, runs to the southeast crossing the Iberic peninsula and has double direction of flight. If we have a look at the chart, we will see that it must be flown on even flight levels from BLV vor to the northwest and also even flight levels from BLV to Barcelona (south-eastwards). Thus, this airway changes its levels of flight at BLV VOR.
From Barcelona towards the east it must be flown on even flight levels until ALG VOR (in Sardinia island)
where we should change to an odd flight level as long as we continue flying UM601 eastward.
As we can see, the UM601 is a good example of an airway using double direction and changing levels of flight depending on the segment.
Final note:
When I control, sometimes I find pilots asking me why I change their flight levels and whether this is a particular case for Spain. Normally what happens is that those pilots still do not know what is an airway and that the European airspace is a single one for all European countries since 2004.
VATSIM is putting a great effort in the Pilot Resource Centre (
http://www.vatsim.net/prc∞) and it is a wise decision, even for experienced simmers, to regularly have a look in it and learn or refresh our knowledge.
Acknowledgements:
Thanks to all VATSIM members which actively participate in discussions of subjects like this in the mail list of the Spanish vACC. I am specially indebted to Francisco Urqu?a and Pepe Morales, real ATCs, for their comments, contributions and suggestions, and also to Joaquin Blanco for providing me with the information regarding the enroute charts for U.S.A. and Canada.
I hope that this article will be useful to make more realistic our simulation experience and keep always in mind that the best we perform our role in VATSIM skies, the more the others will enjoy our company.
I wait for you somewhere at Barcelona (LECB) FIR in VATSIM, of course.
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