# Are the airspace times of operation days of the week in local or Zulu time?

The margin of the Enroute High sectional H-4 claims that the times of operation of the airspace R-5107K near El Paso are "1400-0300Z, MON-FRI" (and other times by NOTAM).

If the days of the week are Zulu time then by converting this to local time would yield "0800-2100, MON-THU".

You could argue against this interpretation because usually, we use the days of the week to reference the starting time, which would mean that the airspace is available starting at "1400Z MON-FRI" which is still "0800 MON-FRI" when converted to local.

But that doesn't explain that on the Enroute Low sectional L-5 the OUTLAW MOA is available "0100-0500Z, MON-FRI by NOTAM".

If the days of the week are ZUlu time, converting that starting time to local time would yield "1800-2200, SUN-THU".

Assuming the NOTAM for this airspace is active, do they really mean that the airspace is active "1800-2200, SUN-THU"? or do they mean that it is active "1800-2200, MON-FRI"?

• Related to: this and this – guest Jan 21 '20 at 0:03
• I don't have a reference to prove my point so I won't make this an answer, but I think that you are overthinking this... It should quite obvious to most that the intent is that the days of the week are the standard local workdays, but that the operating times are Z. Sure, plenty of businesses are open on weekends, and perhaps close on a Monday, but not so much the government. To force people to interpret it in the way you are would be much too confusing. – Michael Hall Jan 21 '20 at 1:09

On the VFR chart for OUTLAW MOA it lists the time of operation as "1800-2200, MON-FRI" which would imply that the days of the week being used for the IFR chart are the local days of the week. See this margin on the Phoenix VFR chart:

A different question answered that the FAA publishes these details of SUA in the JO 7400.10A "Special Use Airspace" and that all of the times in that document are local time.

If we look at OUTLAW MOA in this document, it also shows "1800-2200, MON-FRI".

I think that this is enough evidence for me to accept that the days of the week on the IFR charts are actually in local time even though the times of day are in Zulu time.

The VFR chart covering this area shows local times instead.

For this restricted area, it is 7 AM to 8 PM Mountain time MON-FRI.

• That's different - those times are local, not Zulu. The question asks about times that are explicitly marked Z, so this is irrelevant. – Toby Speight Jan 22 '20 at 13:25
• @TobySpeight The original poster was confused about the times. This is the same restricted area on a different chart. Restricted area R-5107 K is clearly open 7 AM to 8 PM Mountain time. Mountain time is -7 hours different from Zulu, so that is the offset that they need to use on the IFR chart. – JScarry Jan 22 '20 at 16:03
• Ah, I understand the relevance now. I've proposed an edit which I think makes that clearer, and emphasises the days, since that's the focus of the question. That said, guest was more interested in OUTLAW MOA, which changes day when converted between timezones. – Toby Speight Jan 22 '20 at 17:04
• @TobySpeight is correct, I'm much more interested in OUTLAW MOA specifically because of the day issue when changing time zones – guest Jan 22 '20 at 17:26