Common coding patterns

A schedule/timetable is a description of a series of discrete time periods, which occur cyclically within the overall validity time of a feature TimeSlice. Some examples of schedules are:

"daily from 09:00 to 17:00"
"every Monday and Friday from 13:00 to sunset"
"every week from MON 07:00 till FRI 17:00, except HOL"
etc.

AIXM supports the encoding of schedules that contain both:

repetitive time periods, such as "daily...", "every MON...", "SAT 09:00 - SUN 19:00", etc.
occasional occurrences, such as "on 1, 2, 15 and 25 of October", "on 1/10 09:00-15:00 and on 3/10 10:00-12:00", etc.

This section describes the most frequently encountered types of schedules used in the aeronautical information domain. Application developers might consider offering HMI templates for such situations, in order to facilitate a correct and harmonised encoding of such common schedules.

Coded value schedules

The following codes are sometimes used in aeronautical information publications and messages in order to indicate the opening hours of a facility or the operating times of a service: H24, HJ, HN, HX, HO, NOTAM. The following table contains the coding recommendations for these coded values:

Coded value

(meaning)

AIXM coding

Remarks

H24

(continuous service, 24/7)

A single Timesheet:

timeReference=('UTC')
dailightSavingAdjust='NO' or nilReason='inapplicable'
day='ANY'
dayTil='ANY'
startTime='00:00'
endTime='00:00'
excluded = 'NO'

According to the AIXM rules for PropertiesWithSchedule, a property that has a constant value (such as an AirspaceLayerClass that does not change according to a schedule) does not need a schedule to be coded. However, some data providers might considers necessary to give an explicit indication that the service or facility is explicitly provided H24, by coding a "H24 schedule"

HJ

(sunrise to sunset)

A single Timesheet with:

timeReference=('UTC')
dailightSavingAdjust='NO' or nilReason='inapplicable'
day='ANY'
startEvent='SR'
endEvent='SS'
excluded = 'NO'

It is assumed that HJ means 'sunrise to sunset'. If HJ actually means 'sunrise minus xx minutes' to 'sunset plus xx minutes', then the additional minutes should be coded as startTimeRelativeEvent and endTimeRelativeEvent respectively.

For States that apply the "SERA Regulation" (European Union Commission Implementing Regulation (EU) No 923/2012), ‘night’ might actually mean "the hours between the end of evening civil twilight and the beginning of morning civil twilight. Civil twilight ends in the evening when the centre of the sun’s disc is 6 degrees below the horizon and begins in the morning when the centre of the sun’s disc is 6 degrees below the horizon." In this case, different values should be use for start/end event:

startEvent='OTHER:START_MORNING_CIVIL_TWILIGHT'
endEvent='OTHER:END_EVENING_CIVIL_TWILIGHT'

HN

(sunset to sunrise)

A single Timesheet with:

timeReference=('UTC')
dailightSavingAdjust='NO' or nilReason='inapplicable'
day='ANY'
dayTil='ANY'
startEvent='SS'
endEvent='SR'
excluded = 'NO'

It is assumed that HN means 'sunset to sunrise'. If HN actually means 'sunset plus xx minutes' to 'sunrise minus xx minutes', then the additional minutes should be coded as startTimeRelativeEvent and endTimeRelativeEvent respectively.

For States that apply the "SERA Regulation\'",different values should be used for start/end event:

startEvent='OTHER:END_EVENING_CIVIL_TWILIGHT'
endEvent='OTHER:START_MORNING_CIVIL_TWILIGHT'

HX

(no specific working hours)

No Timesheet.

Use an associated Note with propertyName = 'timeInterval', purpose = 'DESCRIPTION' and note='HX (no specific working hours)'

HO

(service available to meet operational requests)

No Timesheet.

Use an associated Note with propertyName = 'timeInterval', purpose = 'DESCRIPTION' and note='HO (service available to meet operational requests)'

NOTAM

(activity periods to be published by NOTAM)

No Timesheet.

Use an associated Note with propertyName = 'timeInterval', purpose = 'DESCRIPTION' and note='activity periods to be published by NOTAM'

"Daily" schedules

This applies to schedules that occur every day during the validity period of the data, without distinction between weekdays. However, it is possible to exclude specific dates from the applicable times of the schedule. For example:

"daily from 09:00 to 17:00"
"daily from SR+30 min until SS or 18:00, whichever is earliest"
"daily from 07:00 to 23:00 except for 25 Dec and 1st Jan"

The data elements that are specified for such schedules are indicated in the diagram below:

where Start_Event and End_Event are detailed in the following diagrams:

EBNF source code for the diagrams

Template_Daily = "[TSH]" ["start date" "end date"] ("start time" | "Start_Event") ("end time" | "End_Event") {note} "[/TSH]" { "[TSH]" ["start date" "end date"] ("start time" | "Start_Event") ("end time" | "End_Event") {note} "[/TSH]"} \n 
{"[TSH]" "excluded date" {note} "[/TSH]"} {"schedule note"}. 

Template_Start_Event = "start event" ["rel. start"] ["start time" "switch"].

Template_End_Event = "end event" ["rel. end"] ["end time" "switch"].

The graphical elements included in this diagram have the meaning explained in the following table:

*Item*	*Coding*	*Comments*
[TS] and [/TS]	All the elements that appear between [TS] and [/TS] are encoded as a single timesheet
start date	Timesheet.startDate
end date	Timesheet.endDate
start time	Encoded as Timesheet.startTime
start event	Encoded as Timesheet.startEvent
rel. start	Encoded as Timesheet.startTimeRelativeEvent	Positive values indicate that the actual start time is after the event.
switch	Encoded as startTimeRelativeEvent	Indicates which one takes precedence between the start/end time and the start/end event (including the eventual time relative to the event)
end time	Encoded as Timesheet.endTime
end event	Encoded as Timesheet.endEvent
rel. end	Encoded as Timesheet.sendTimeRelativeEvent	Positive values indicate that the actual end time is after the event.
note	Encoded as Timesheet.annotation	Examples of such notes: "Departures till 2000 LT. However, latest ready time (with explanation of what that implies) is then often 15 minutes earlier or the departure"
excluded date	Each excluded date is coded as a separate Timesheet with excluded='YES', startDate equal the "excluded date", endDate equal to "excluded date +1 day", day='ANY', dayTill='ANY', startTime='00:00', endTime='00:00', timeReference='UTC+/-X' (local time as UTC zone).
schedule note	Encoded as Note associated with the class that owns the schedule, with propertyName='timeInterval' and purpose='REMARK'.

"Days of the week" schedules

This applies to schedules that occur with a weekly pattern, during the validity period of the data. It is possible to specify both individual weekdays (MON, TUE, etc.) and weekday ranges (from FRI 17:00 to MON 07:00). It is possible to exclude specific dates or special days (such as holidays) from the applicable times of the schedule. For example:

"MON, TUE, WED, THU, FRI from 13:00 to sunset; SAT, SUN. from 13:00 to 15:00"
"SUN, 2300 (2200) to MON, 0500 (0400)"
"MON to FRI, 09:00 to 17:00, excluding HOL"

The data elements that are specified for such schedules are indicated in the following diagram:

where Start_Event and End_Event are detailed in the following diagrams:

EBNF source code for the diagrams

Template_Weekdays = "[TSH]" ["start date" "end date"] ("on weekday" {"on weekday"} ("start time" | "Start_Event") ("end time" | "End_Event") | "from weekday" ("start time" | "Start_Event") "to weekday" ("end time" | "End_Event")) {note} "[/TSH]" {"[TSH]" ["start date" "end date"] ("on weekday" {"on weekday"} ("start time" | "Start_Event") ("end time" | "End_Event") | "from weekday" ("start time" | "Start_Event") "to weekday" ("end time" | "End_Event")) {note} "[/TSH]"} \n
{"[TSH]" ("excluded date" | ["start date" "end date"] "excluded day") {note} "[/TSH]"} {"schedule note"}.
Template_Start_Event = "start event" ["rel. start"] ["start time" "switch"].

Template_End_Event = "end event" ["rel. end"] ["end time" "switch"].

The graphical elements included in this diagram have the meaning explained in the following table:

*Item*	*Coding*	*Comments*
[TS] and [/TS]	All the elements that appear between [TS] and [/TS] are encoded as a single timesheet
start date	Timesheet.startDate
end date	Timesheet.endDate
on weekday	Encoded as Timesheet.day	Any weekday values is allowed, including HOL
from weekday	Encoded as Timesheet.day	Any weekday values is allowed, including HOL
to weekday	Encoded as Timesheet.dayTil	Any weekday values is allowed, including HOL
start time	Encoded as Timesheet.startTime
start event	Encoded as Timesheet.startEvent
rel. start	Encoded as Timesheet.startTimeRelativeEvent	Positive values indicate that the actual start time is after the event.
switch	Encoded as startTimeRelativeEvent	Indicates which one takes precedence between the start/end time and the start/end event (including the eventual time relative to the event)
end time	Encoded as Timesheet.endTime
end event	Encoded as Timesheet.endEvent
rel. end	Encoded as Timesheet.endTimeRelativeEvent	Positive values indicate that the actual end time is after the event.
note	Encoded as Timesheet.annotation	Examples of such notes: "Departures till 2000 LT. However, latest ready time (with explanation of what that implies) is then often 15 minutes earlier or the departure"
excluded date	Each excluded date is coded as a separate Timesheet with excluded='YES', startDate equal the "excluded date", endDate equal to "excluded date +1 day", day='ANY', dayTil='ANY', startTime='00:00', endTime='00:00', timeReference='UTC+/-X' (local time as UTC zone).
excluded day	Encoded as a separate Timesheet with excluded='YES', day equal to the "excluded day" value, startTime='00:00', dayTil equal to the "next day after the excluded day" value, endTime='00:00', timeReference='UTC+/-XX' (local time expressed as an as UTC zone).	It does not make sense to use the normal days of the week in this case, only 'HOL', 'BEF_HOL', 'AFT_HOL', 'WORK_DAY', 'BEF_WORK_DAY', 'AFT_WORK_DAY', 'BUSY_FRI' make sense here
schedule note	Encoded as Note associated with the class that owns the schedule, with propertyName='timeInterval' and purpose='REMARK'.