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For "ENR 3.3 Area navigation routes", PANS-AIM explicitly requires that the magnetic bearing of the route segment is provided. For all other routes defined in ENR 3 PANS-AIM requires a track or VOR radial without defining if it is true or magneticapplying the following note
Bearings, tracks and radials are normally magnetic. In areas of high latitude, where it is determined by the appropriate authority that reference to Magnetic North is impractical, another suitable reference, i.e. True North or Grid North, may be used.
Tracks and reverse tracks if any, have to be encoded taking into account the implicit direction of the route segment, i.e. the defined start and end point, (see also above). In this regard the tracks are considered to be from the start point of the segment whereas the reverse tracks are considred to be to from the end point of the route segment.
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For "ENR 3.1 Lower ATS routes" and "ENR 3.2 Upper ATS routes", PANS-AIM requires the provison of lateral limits.
The RouteSegment class provides the attributes widthLeft and widthRight to define the lateral limits. These are the distances from the centreline of the route segment to the left and right edge respectivley. For example, if the route segment has a defined width of 10 NM for each of the attributes will carry the value '5' uom equal-to 'NM'.
Vertical Limits
PANSAIM PANS-AIM requires different vertical limits to be specified depending on the type of route.the purpose and classification of the route.
The following table gives an overview which vertical limits are required by PANS-AIM taking into account the defined properties and route sections and the corresponding AIXM attributes of the RouteSegment class (NOTE 1) :
| AIXM 5.1.1 RouteSegment attributes | PANS-AIM | |||||||
|---|---|---|---|---|---|---|---|---|
| Attribute | Description | Property | ENR 3.1 Lower ATS routes | ENR 3.2 Upper ATS routes | ENR 3.3 Area navigation routes | ENR 3.4 Helicopter routes | ENR 3.5 Other routes | Remarks |
| upperLimit | The vertical position of the route segment ceiling. | Upper limit | x | X | X | X | ||
| lowerLimit | The vertical position of the route segment floor. | Lower limit | x (Note 2) | X | X | X | ||
| minimumObstacleClearingAltitude | Minimum obstacle clearance altitude (MOCA). The minimum altitude for a defined segment of flight that provides the required obstacle clearance. | MOCA | x | |||||
| minimumEnrouteAltitude | Minimum en-route altitude (MEA). The altitude for an en-route segment that provides adequate reception of relevant navigation facilities and ATS communications, complies with the airspace structure and provides the required obstacle clearance. | MEA | x (Note 2) | |||||
| minimumCrossingAtEnd | The lowermost vertical position at the end point, when flying on the route portion in the direction indicated in the RoutePortionUsage. | NA | ||||||
| maximumCrossingAtEnd | The uppermost vertical position at the end point, when flying on the route portion in the direction indicated in the RoutePortionUsage. | NA | ||||||
| NA | Minimum flight altitude | X | ||||||
| Note | ||
|---|---|---|
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| PANS-AIM defines more vertical limits, i.e Area Minimum Altitude (AMA) and Minimum Vectoring Altitude (MVA) which are not considered as part of the AIP Data set and hence are not conatined in the table. |
| Note | ||
|---|---|---|
| ||
| Either lower limits or minimum en-route altitudes shall be defined. |
| Info | ||
|---|---|---|
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Isn't the MOCA and the Minimum flight altitude the same "thing? the First is used for ENR 3.1 Lower TAS routes and the latter is used only for ENR 3.4 Helicopter routes ? |
Regarding vertical limits of en-route routes different terminologies and concepts are used in the aviation world.
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