Aviation Topic of the Week
By Michael Oxner, April 11, 2004


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This week's topic:
Understanding NOTAMs, Part 2

Last week, we looked at the general information about NOTAMs. This week, we'll take a look at the way NOTAMs are formatted and some examples. The AIP, MAP 5.6 is our reference for this week's material. The example used is also taken directly from there.

New NOTAM
Replacing NOTAM
Cancelling NOTAM
RSC/CRFI NOTAM
Other

New NOTAM

GG  CYZZNYOW
141736  CYNDYFYX
980007  NOTAMN  CYOW  OTTAWA/MACDONALD-CARTIER INTL
CYOW  ILS 07  U/S TIL APRX 9801191200


Line by line, segment by segment, here is how the above NOTAM example is decoded.

Line 1: Line 2:
Line 3:
Line 4:
I think another note about date-time groups, also revolving around midnight (0000z), is worth mentioning. There has been some confusion in the past for many individuals regarding the application of the time 0000. Does, for example, 190000 refer to the midnight at the start of the 19th, or the end as we change over to the 20th? Personally, I don't see the problem with this. We go from 0000 to 2359 on one day, then the next 0000 is for the following day. That said, to avoid such confusion, NOTAMs changing over at 0000z, on a given day will often start at 0001 and end at 2359 to help NOTAM readers positively identify the correct date. A NOTAM regarding a particular condition might start at 200001 and end on 202359, meaning that the whole event/concern starts and ends only on the 20th day of the month.

Replacing NOTAM

In the example above, a specific date time group was not published for the return to service of the ILS 07. Since the term "TIL APRX" was used, an update must be published as well. This will take the form of a Replacing NOTAM.

980008  NOTAMR  980007  CYOW OTTAWA/MACDONALD-CARTIER INTL
CYOW  ILS 07 U/S  TIL  APRX  9801191800


Line 1:
Line 2:
Again, this NOTAM requires an update.

Cancelling NOTAM

Finally, they have the darned thing back in operation. Now they have to cancel the previous NOTAMR, since the "TIL APRX" is not specific enough for an automatic "timeout" of the condition.

980009  NOTAMC  980008  CYOW OTTAWA/MACDONALD-CARTIER INTL
CYOW  ILS 07  SVCBL

Line 1:
Line 2:
RSC/CRFI NOTAM

Now a new type, which we have seen examples of in the past in these topics.

980010  NOTAMJ  CYND  OTTAWA/GATINEAU
CYND  RSC  09/27  SNOW DRIFTS  3-4 INS  9801191150
CYND  CRFI  09/27  -10  .30 9801191150


Line 1:
Line 2:
Line 3:
Other

There is at least one other type of NOTAM mentioned in the AIP, and I'll only casually mention it here. The NOTAMQ is a Query/Response NOTAM. I won't go into detail on it for a couple of reasons. I haven't had the need to read anything on this, and the AIP doesn't have much on it, either. If you're not the one using the teletype, I doubt you'll have much of a need to understand this type.




Apart from decoding some of the terms, that should be all there really is to understanding NOTAMs. If you have any questions, please e-mail me at moxner@nbnet.nb.ca. Thanks, as usual, for taking the time to read!