[AIXM-501] Interpretation of speed limitations on Segment Leg

Description

The speedInterpretation data type is corrected by replacing the incorrect use of the CodeAltitudeUseType with a dedicated CodeSpeedInterpretationUseType.

Rationale for change

See https://aixmccb.atlassian.net/browse/AIXM-116

In the current model, the speedInterpretation attribute of the SegmentLeg class uses the CodeAltitudeUseType. This is incorrect both from a conceptual point of view and also from the actual list of values for this data type. A dedicated speed limit interpretation list of values is necessary.

As per ARINC 424-221 5.261 Speed Limit Description, there are 3 (three) values detailing the description of speed limit. These values are optional for all Path Terminators, irrespective of the fix association (Ref. ARINC 424-22 Att 5).

• “+” Minimum Speed, Cross Fix AT or ABOVE speed specified in Speed Limit
• “-” Maximum Speed, Cross Fix AT or BELOW speed specified in Speed Limit
• “@ or blank” Mandatory Speed, Cross Fix AT speed specified in Speed Limit

General interpretation:

• MAX=”Maximum speed” - Maximum speed limit associated with the leg;
• MIN = “Minimum speed” - Minimum speed limit associated with the leg;
• AT = “Mandatory speed” - Mandatory speed limit associated with the leg.

Translating these ARINC rules in full, to support a wider scope of implementation, based only on the current AIXM 5.1(.1)+ Segment Leg logic, is not possible at the level of the UML model and they would need to be addressed by additional interpretation provided in appropriate coding guidelines.

Impact assessment

[FWD_MAP_1:1] Data mapping is possible and no data loss occurs when data is exchanged from a system (A) that uses AIXM 5.1.1 for output towards a system (B) that uses AIXM 5.2 for input.

[BWD_MAP_1:1] Data mapping is possible and no data loss occurs when data is exchanged from a system (B) that uses AIXM 5.2 for output towards a system (A) that uses AIXM 5.1.1 for input.

Mapping AIXM 5.1.1 to AIXM 5.2 (forward)

[MAPC-01] For each SegmentLeg specialisation that has an assigned speedInterpretation value equal-to:

• “OTHER:MAX”, “BELOW_UPPER” replace it with “MAX”;
• “OTHER:MIN”, “ABOVE_LOWER” replace it with “MIN”;
• “OTHER:AT”, “AT_LOWER” replace it with “AT”;
• “BETWEEN” replace it with “OTHER:BETWEEN”
• “RECOMMENDED” replace it with “OTHER:RECOMMENDED”
• “EXPECT_LOWER” replace it with “OTHER:EXPECT_LOWER”
• “AS_ASSIGNED” replace it with “OTHER:AS_ASSIGNED”

Mapping AIXM 5.2 to AIXM 5.1.1 (backward)

[MAPC-01] For each SegmentLeg specialisation that has an assigned speedInterpretation value equal-to:

• “MAX” replace it with “OTHER:MAX”
• “MIN” replace it with “OTHER:MIN”
• “AT” replace it with “OTHER:AT”

Mapping example

(Note: for mapping test data see: https://github.com/aixm/mapping_52_511/tree/master/AIXM-xxx) 

AIXM 5.2	AIXM 5.1(.1)