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Active Event (NOTAM in force)


This section provides rules for the coding and NOTAM generation in the case of Events that are already active, The cases discussed here are based on the EUROCONTROL Guidelines Operating Procedures for AIS Dynamic Data (OPADD), Ed.4, section 2.4. With regard to the NOTAM associated with the Event, the following general OPADD rule applies:

2.4.1.5 "The date-time group in Item B) of a NOTAMR or NOTAMC shall be the actual date and time that this NOTAMR or NOTAMC is created.
i.e. NOTAMR and NOTAMC shall take effect immediately and no future start of coming into force is permitted. The replaced or cancelled NOTAM cease to be valid from the very moment their replacing NOTAMR or NOTAMC are issued. This is done to assure the correct processing in all systems regardless of their design."

The initial Event has a valid time starting at T-start and ending at some time T-end in the future. This could also be an estimated termination. The Event is coded with an initial BASELINE TimeSlice 1.0, which corresponds to the TEMPDELTA TimeSlice 1.0 coded for the feature affected by the Event. A NOTAMN is associated with the Event BASELINE 1.0.  

The current time is somewhere in between the start and the end of lifetime of the Event.

Modified termination (in future)


Note

This situation corresponds to the OPADD case described in item 2.4.1.8.

If the condition coded in the Event is to remain valid for a period before the new termination time (T2 on the diagram to the right) is reached, then:

  • for the feature, a correction TimeSlice TEMPDELTA 1.1 needs to be coded, the only change being its modified end of validity. This is coded according to the AIXM Temporality rule TS_017, which allows a correction TimeSlice to have a start of validity in the past, on condition that the only correction made concerns its end of validity;
  • for the Event, a correction TimeSlice BASELINE 1.1 and a new BASELINE 2.0 need to be coded, because a separate NOTAMR needs also to be issued and becomes immediately applicable. The new BASELINE 2.0 is associated only with the NOTAMR.

Immediate termination


If the condition coded in the Event is terminated immediately, then:

  • for the feature, a correction TimeSlice TEMPDELTA 1.1 needs to be coded, the only change being its modified end of validity, which is the current time. This is coded according to the AIXM Temporality rule TS_017, which allows a correction TimeSlice to have a start of validity in the past, on condition that the only correction made concerns its end of validity;
  • for the Event, a correction TimeSlice BASELINE 1.1 needs to be coded, the main change being its end of validity, which becomes the current time. However, a NOTAMC needs also to be issued, effective immediately. By exception to the AIXM Temporality rule TS_017, this NOTAMC is also associated with the correction TimeSlice for the Event (BASELINE 1.1).


Immediate modified feature condition


Note

This situation corresponds to the OPADD case described in item 2.4.1.9.

Sometimes, the condition coded in the Event is changed with immediate effect. For example, the schedule of a runway closure could be modified or the maximum altitude of an airspace reservation might be changed. In this case:

  • for the feature, a new TEMPDELTA 2.0 TimeSlice needs to be coded starting immediately its validity, providing the modified data. Obviously, a correction TimeSlice TEMPDELTA 1.1 needs to be coded as well, terminating immediately the previously valid TEMPDELTA TimeSlice;
  • for the Event, a correction TimeSlice BASELINE 1.1 and a new BASELINE 2.0 need to be coded. According to the OPADD rules for this case, a NOTAMC is usually issued, followed immediately by a NOTAMN. By similarity with the previous two cases, the NOTAMC is associated with the Event BASELINE 1.1, while the new NOTAMN(2) is associated with the new Event BASELINE 2.0. If a NOTAMR is issued instead of the NOTAMC/NOTAMN sequence, then the Event/NOTAM associations become similar to the OPADD case 2.4.1.8 discussed above.


Modified feature condition in future


Note

This situation corresponds to the OPADD case described in item 2.4.1.7.

If the condition coded in the Event is changed sometime in the future, then :

  • for the feature, a new TEMPDELTA 2.0 TimeSlice needs to be coded, providing the modified data. Its start of validity is at the future change date. Obviously, a correction TimeSlice TEMPDELTA 1.1 needs to be coded as well, terminating the previously valid TEMPDELTA TimeSlice at the same time;
  • for the Event, a correction TimeSlice BASELINE 1.1 and two new BASELINE need to be coded. The Event BASELINE 2.0 is associated with a NOTAMR, that modifies the termination date of the current condition. This is similar to the OPADD case 2.4.1.8 discussed above. In addition, the Event BASELINE 3.0 is associated with the new NOTAMN, that provides the changed condition and which becomes valid at the future date/time.


NOTAM R/C production rules


This section provides general rules for the content of the various fields of the NOTAMC and/or NOTAMR indicated in the cases discussed above. In addition, each scenario might have more specific rules for NOTAMR and NOTAMC produced in that scenario.

Item A

NOTAMR and NOTAMC have the same Item A) contents as the NOTAM to be replaced or cancelled. Therefore, this shall be copied from the NOTAM associated with the previous Event BASELINE TimeSlice.

Q code

NOTAM R and NOTAM C deal with precisely the same subject as the NOTAM to be replaced or cancelled. Therefore the 2nd and 3rd letters of the NOTAM code in Item Q) shall be copied from the NOTAM associated with the previous Event BASELINE TimeSlice.

If a NOTAM R is created, then the 4th and 5th letters of the NOTAM code in ITEM Q shall also be copied from the NOTAM associated with the previous Event BASELINE TimeSlice.

If a NOTAM C is created, then the 4th and 5th letters of the NOTAM code in ITEM Q shall be as specified in each individual scenario. Note that according to OPADD version 4.1, item 2.4.3.6, "CN shall be used when cancelling a planned event published by NOTAM, such as navigation warning, planned exercises or work. The code Q - - CN is not intended to be used as a general code for all NOTAMC. To cancel NOTAM events such as closed RWY the use of Q - - AK or Q - - AL is preferred". Therefore, each scenario provides further rules for the Q code of a NOTAMC

Items B, C and D

The value in the item B shall be equal to the validTime.TimePeriod.endPosition of the Event BASELINE 1.1 correction TimeSlice associated with the NOTAM. This is the current date & time of the system, formatted according to the NOTAM syntax for this field: yymmddhhmm.

If a NOTAM C is created, then item C and D shall be left empty.

If a NOTAM R is created, then:

  • item C is derived from the new Event BASELINE 2.0 TimeSlice associated with the NOTAM, applying the following rules:
    • if not NIL, use the value of the validTime.TimePeriod.endPosition property. If this element is empty and it has an attribute indeterminatePosition='unknown', then use the value of the Event.estimatedValidity followed by the keyword 'EST'.

    • the date/time value in item C shall be formatted as follows
      • if the time value of endPosition time group is 00:00 or 00:00:00, then the previous day shall be used in the date group and the value “2359” shall be used as hhmm group. That's because, according to the AIXM Temporality Concept 1.1, the value 24:00 cannot be used for the validTime.TimePeriod.endPosition, being replaced with "00:00" on the next day.
      • otherwise, the value is used as such.
  • in item D, copy the value from the NOTAM associated with the previous Event BASELINE TimeSlice, adjusted so that its first time period is equal to the value in item B of the NOTAM (as requested by OPADD):
    • delete all date&times which are earlier than the value in item B;

    • for the first date, adjust the beginning of the time to the value in item B;

    • if the new end of validity is after the end of the original validity, add any additional date×

    • if the new end of validity is before the end of the original validity, delete any date&times after the end of validity.

Item E

If a NOTAM R is created, then copy the value of the item E from the NOTAM associated with the previous Event BASELINE TimeSlice.

If a NOTAM C is created, follow the rules provided for each particular Event scenario, under title "Event update". For example:

  • for cancelling the temporary activation of a special activity area, see Published special activity area - activation / Event Update;
  • for cancelling the temporary operational status change of a navaid, see Navaid unserviceable / Event Update;
  • Etc.

Items F & G

If a NOTAM R is created, then copy the values of the F and G items respectively, from the NOTAM associated with the previous Event BASELINE TimeSlice.

If a NOTAM C is created, then item F and G shall be left empty.

Inactive Event (NOTAM not in force)


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