For the sake of simplicity, let's assume the following examples are valid from 2022-01-01 thru 2022-01-31.
D items (which specify the exact validity periods of the NOTAM) may span across midnight as follows:
D) 01-10 2100-0600
This is to be interpreted as follows:
Valid for ten nights beginning with 2022-01-01 21:00 thru 2022-01-02 06:00 and ending with 2022-01-10 21:00 thru 2022-01-11.
So even though the dates mention only
01-10, January 11 is also included as the times span across midnight. So far, so easy.
Things get hairy once exceptions are added to the mix:
D) 01-10 2100-0600 EXC WED
The only Wednesday in that period is on 2022-01-05. The above can be interpreted in two ways:
- On exactly 2022-01-05, the times do not apply. So the NOTAM is not valid that Wednesday from midnight to 06:00 and from 21:00 to midnight.
- The entire period starting 2022-01-05 is excluded. So the NOTAM is not valid that Wednesday from 21:00 thru the following Thursday 06:00.
I tend towards interpretation 2 since the other interpretation produces somewhat fragmented validities and I'm having a hard time imagining a situation where this actually makes sense.
But I can't find any hint about this case in the documentations. Has anybody seen such a case in the wild? Or maybe some more detailed official guide as of how to interpret such cases?
Thanks a lot!