Coding

Definition

The surface condition report event scenario describes informations about contaminations on one or multiple runways, taxiways and/or aprons at one airport.

Notes:

• The objective of this scenario is to support the encoding of contamination information about individual runways, taxiways or aprons, as contained in SNOWTAM messages;
• Several runways, 
• The content of the SNOWTAM is considered as described in ICAO Doc 10066 - Aeronautical Information Management, First Edition, 2018, Appendix 4. 
• This scenario does not support the encoding of the information about airport, runway closure due to contamination. That information should be encoded using the dedicated AD.CLS or RWY.CLS scenarios.

Event data

The following diagram identifies the information items that are usually provided by a data originator for this kind of event.

input = "airport designator" ["name"] \n 
"runway_condition" {"runway_condition"} \n
["taxiway designator" ["taxiway snow bank presence"]["taxiway surface condition"]] \n
["apron designator" "apron surface condition"] \n
["measured friction coefficient" "friction measuring device"] \n
{"note"}.


runway_condition = "assessment date and time" "runway designator" "rwy_section_input" {"rwy_section_input"} ["reduced runway width"] ["reduced runway length"] ["special conditions"] \n
["snow bank side" "snow bank distance" {"snow bank side" "snow bank distance"}] \n ["adjacent snow bank presence"] .


rwy_section_input = "runway section" "RWYCC on runway section" ["contaminant coverage"] ["loose contaminant depth"] ["contaminant layer order"] "condition description" {["contaminant layer order"] "condition description"}.

Assumptions for baseline data

It is assumed that information about the aerodrome already exists in the form of :

AirportHeliport BASELINE TimeSlice(s) covering the complete period of validity of the event, for which the baseline availability is coded as specified in the Coding Guidelines for the (ICAO) AIP Data Set.

Data encoding rules

The data encoding rules provided in this section shall be followed in order to ensure the harmonisation of the digital encodings provided by different sources. To the maximum possible extent, the compliance with these encoding rules shall be verified with automatic data validation rules.

Decoding

Text NOTAM production rules

This section provides rules for the automated production of the text NOTAM message items, based on the AIXM 5.1 data encoding of the Event. Therefore, AIXM specific terms are used, such as names of features and properties, types of TimeSlices, etc:

• the abbreviation RWY.BL. indicates that the corresponding data item must be taken from the Runway BASELINE associated with the Event;
• the abbreviation TWY.BL. indicates that the corresponding data item must be taken from the Taxiway BASELINE associated with the Event;
• the abbreviation APN.BL. indicates that the corresponding data item must be taken from the Apron BASELINE associated with the Event;
• the abbreviation AHP.BL. indicates that the corresponding data item must be taken from the AirportHeliport BASELINE associated with the Runway concerned;
• the abbreviation RWY.TD. indicates that the corresponding data item must be taken from the Runway TEMPDELTA that was created for the Event;
• the abbreviation TWY.TD. indicates that the corresponding data item must be taken from the Taxiway TEMPDELTA that was created for the Event;
• the abbreviation APN.TD. indicates that the corresponding data item must be taken from the Apron TEMPDELTA that was created for the Event;

In general, the ICAO DOC 8126, OPADD rules and ICAO DOC 10066  shall be followed. These have not been copied in this document in order to avoid duplication with those documents. Only instructions that are specific to the AIXM encoding of this event are stated here.

Abbreviated heading

Kept here as it might be needed for transition phases and communication with legacy systems. Unclear if it is still to be kept. 

The following AIXM elements should be used for automatically generating the SNOWTAM Abbreviated heading text from the AIXM data:

Item A

The item A shall contain the AHP.BL.designator if AHP.BL.locationIndicatorICAO='YES'. Otherwise, the nationality letter(s) as defined in ICAO Doc 7910 followed by “XX” or “XXX”. 

Item B

Item B shall contain the RWY.TD.overallContaminant.observationTime formatted according to the following syntax: mmddhhmm (month-day-hour-minutes).

Item C

Item C shall contain the lower runway designator number of the Runway.designator for which the assessment is concerned. For example, if the runway designator is "09L/27R", only "09L" shall be inserted.

Item D

RWYCC_AIXM_Placeholder

Item E

If provided, insert here the Runway.RunwaySectionContamination.proportion values for each runway third formatted as follows: [n]nn/[n]nn/[n]nn.

If the conditions are not reported, insert here "NR" for the appropriate runway third(s). 

Item F

If provided, insert here the Runway.RunwaySectionContamination.depth for each runway third formatted as follows: nn/nn/nn or nnn/nnn/nnn.

Item G

Insert here the condition description decoded as follows:

If Runway.RunwaySectionContamination.SurfaceContaminationLayer.layerOrder is provided, insert here the condition description decoded as follows,: 

Decoding of SurfaceContaminationLayer.type with layerOrder=1 followed by "on top of" SurfaceContaminationLayer.type with layerOrder=2. Only following are allowed:

• "Dry snow on top of compacted snow"
• "Dry snow on top of ice"
• "Water on top of compacted snow"
  
• "Wet snow on top of compacted snow"
• "Wet snow on top of ice"

If the conditions are not reported, insert here "NR" for the appropriate runway third(s). 

Item H

Insert here the Runway.overallContaminant.RunwayContamination.clearedWidth decoded according to the {{text NOTAM production rules for distances}}.

Item I

Insert here the applicable lower runway designator number of the Runway.designator for which the assessment is concerned followed by the Runway.overallContaminant.RunwayContamination.clearedLength decoded according to the {{text NOTAM production rules for distances}}. 

 This information is conditional when a NOTAM has been published with a new set of declared distances!

Item J, Item K and Item L

Insert here the condition description decoded as follows:

Item M

If provided, insert here the lower runway designator number of the Runway.designator for which the assessment is concerned followed by "Snow bank" and Runway.overallContaminant.criticalRidge.side decoded as follows: 

followed by SnowBank_CLdistance_AIXM_Placeholder decoded according to the {{text NOTAM production rules for distances}} followed by "from centreline". 

Item N

If there exists any TWY.TD.TaxiwayContamination.Ridge.annotation with purpose=REMARK and note="Snow banks present on the taxiway" insert here the TWY.BL.designator followed by "Snow bank"

Item O

If there exists any RWY.TD.RunwayContamination.Ridge.annotation with purpose=REMARK and note="Snow banks present on the taxiway" insert here the TWY.BL.designator followed by "Snow banks present adjacent to the runway" insert here the lower runway designator number of the Runway.designator for which the assessment is concerned followed by "Adjacent snow banks"

Item P

If there exists any TWY.TD.SurfaceCharacteristics.surfaceCondition=POOR insert here the TWY.BL.designator followed by "Poor".

If all TWY.BL associated with AHP.BL have a TWY.TD.SurfaceCharacteristics.surfaceCondition=POOR insert here "All TWYs poor".

Item R

If there exists any APN.TD.SurfaceCharacteristics.surfaceCondition=POOR insert here the APN.BL.designator followed by "Poor".

If all APN.BL associated with AHP.BL have a APN.TD.SurfaceCharacteristics.surfaceCondition=POOR insert here "All aprons poor".

Item S

Insert here the Runway.RunwayContamination.frictionCoefficient as string value.  and the Runway.RunwayContamination.frictionDevice decoded as follows:

Item T

Annotations shall be translated into free text according to the rule for {{decoding annotations}}.

B to H are repeatable

Unit of measurement are not reported

Maximum validity 8h 

A SNOWTAM cancels the precious SNOWTAM.