Software test question wrong or is it me?

[Kodiak]

I am being vexed on this question. I think that I have answered it correctly and the
test software is wrong. The Chart Supplement says that fuel is available from 1300-0500Z.
Since it is in September in Ohio, it is DST. Therefore, you would subtract 4 from the
1300 and the 0500 = 0900-0100 local time. Am I not correct?


Chart Supplement:
TOLEDO EXPRESS (TOL) 10W UTC—5(—4DT)
AIRPORT REMARKS: Attended continuously. Fuel and svc avbl 1300-05000Z.

Question:
According to the Chart Supplement, what times can a pilot obtain fuel and services in
September at Toledo Express (TOL) Airport?

A. 0900 - 0100 hr. local time.
B. 1300 - 0500 hr. local time.
C. 0800 - 0000 hr. local time

My answer: A. 0900 - 0100 hr. local time.

The software explanation:
(A) is incorrect.
This answer subtracts 4 hr. from 1300-0500Z++, neglecting to consider the 1 additional earlier hr.

Thanks.

 

[Kodiak]

Found the answer. The software doesn't include an explanation as to what the ++ after the 1300-0500Z‡ means until after you get the answer wrong.
Here is the explanation:
The ‡ symbol specifies that during daylight saving time, the services are available 1 hr. earlier than shown. During standard time, 5 hr. are subtracted
from Zulu time. During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol).

 

[flyingron]

Yep, that is a correct interpretation. This is pretty common in the Chart Supplement (former AFD) reflecting that the hours really don't change with local DST application. Since they convert them to Zulu, the Zulu hours have to change (even thought he local doesn't) with the DST application. That's what the double-dagger means (you may wish to spend some time reading through the front of the Chart Supplement book... This is one of those things that tends to get lost for people who only access the airport page on efbs.

 

[dtuuri]

I think YOU are right. Here, let's parse it together (from the CS legend):

"Hours of operation of all facilities are expressed in Coordinated Universal Time (UTC) and shown as “Z” time.

The directory indicates the number of hours to be subtracted from UTC to obtain local standard time and local daylight saving time UTC–5(–4DT).

The symbol ‡ indicates that during periods of Daylight Saving Time (DST) effective hours will be one hour earlier than shown.

In those areas where daylight saving time is not observed the (–4DT) and ‡ will not be shown.

...

If the state observes daylight saving time and the operating times are other than daylight saving times, the operating hours will include the dates, times and no ‡ symbol will be shown, i.e., April 15–Aug 31 0630–1700Z, Sep 1–Apr 14 0600–1700Z"​

The ++ thingy is separate from the -4 thingy, so you don't apply them both at the same time, IMO.

 

[RyanB]

During standard time, 5 hr. are subtracted
from Zulu time. During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol).

For the Eastern Time Zone that would be correct.

 

[dtuuri]

For the Eastern Time Zone that would be correct.

Uh, no. It's 13Z to 05Z++. That ++ means 1 hour earlier than "Standard 'Z' time" (see first sentence in legend above).

 

[RyanB]

Uh, no

Uh, yes actually.

During standard time, 5 hr. are subtracted
from Zulu time. During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol).

Toledo Express is in the Eastern Time Zone, so these corrections would be correct, as I pointed out. If this was referring to somewhere in the Central, Mountain or Pacific time zones, than you’d have to adjust for daylight savings and standard time accordingly as it would not be the same (-5 Standard or -4 Daylight Savings) as Eastern.

 

[dtuuri]

Uh, yes actually.


Toledo Express is in the Eastern Time Zone, so these corrections would be correct, as I pointed out. If this was referring to somewhere in the Central, Mountain or Pacific time zones, than you’d have to adjust for daylight savings and standard time accordingly as it would not be the same (-5 Standard or -4 Daylight Savings) as Eastern.

I'm not disagreeing with the DST corrections. I'm saying you don't apply them TWICE.

 

[RyanB]

I'm not disagreeing with the DST corrections. I'm saying you don't apply them TWICE.

I’m not saying you apply them twice either, not sure how you got that out of the post I made.

 

[dtuuri]

I’m not saying you apply them twice either, not sure how you got that out of the post I made.

You are agreeing with the test software explanation cited by Kodiak?

"During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol)."​

That's twice.

 

[RyanB]

You are agreeing with the test software explanation cited by Kodiak?

Yes, it is correct.

The one hour is already subtracted hence the symbol. You’re trying to do it twice.

 

[dtuuri]

Yes, it is correct.

You wrote it, dintcha.

The one hour is already subtracted hence the symbol. You’re trying to do it twice.

Only once: 13z to 05z++ = 08 EDT to 00 EDT

 

[RyanB]

You wrote it, dintcha.


Only once: 13z to 05z++ = 08 EDT to 00 EDT

So the test software is wrong and you’re correct?

You’re misinterpreting it, sir. The explanation is quite clear.

 

[dtuuri]

So the test software is wrong and you’re correct?

You’re misinterpreting it, sir. The explanation is quite clear.

Whaaaa???? Hmm, something looked sooo wrong until now. Ok, move along, nothin' to see here.

 

[RyanB]

 

[midlifeflyer]

Just stumbled on this and I'm confused. Not by the question but by the discussion

The double-dagger (‡) is just a form of asterisk. You will see it, along with the other flavors, all over the place in charts and related materials. In this case the asterisk says that "during daylight saving time, the services are available 1 hr. earlier than shown."

So, instead of opening 1300Z and closing a 0500Z, the FBO operates 1200Z to 0400Z.

Apply the proper Zulu to local time conversion for daylight savings (-4) and you get 0800-0000 local.

 

[RyanB]

Just stumbled on this and I'm confused. Not by the question but by the discussion

The double-dagger (‡) is just a form of asterisk. You will see it, along with the other flavors, all over the place in charts and related materials. In this case the asterisk says that "during daylight saving time, the services are available 1 hr. earlier than shown."

So, instead of opening 1300Z and closing a 0500Z, the FBO operates 1200Z to 0400Z.

Apply the proper Zulu to local time conversion for daylight savings (-4) and you get 0800-0000 local.

Yup! The explanation was quite clear to me as well.

 

[dtuuri]

It was this line that threw me:

"During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol)."​

Seemed like "double jeopardy" (for the lawyers in the house) to me. But I've recanted my testimony, so to speak.

 

[midlifeflyer]

It was this line that threw me:

"During daylight saving time, 4 hr. are subtracted from 1200-0400 (1 hr. is already subtracted due to the ‡ symbol)."​

Seemed like "double jeopardy" (for the lawyers in the house) to me. But I've recanted my testimony, so to speak.

It's a confusing explanation. Essentially, it takes two steps - apply the ‡ to the Zulu time frame, and convert the result to local time - and tries to combine them into one.

 

[flyingron]

The FBO is open 8AM to Midnight local time year round. The problem is that this means it's 1300-0500 Z in the winter, and 1200-0400 Z in the summer. The double dagger notation in the CS is an attempt to relate something that's defined in LOCAL TIME (in a place that has daylight savings time) in Zulu. Now if you see the double-dagger you have two choices:

1. Forget about DST in the calculation at all, the ours are applied by the standard time offset (-5) year round.
2. Apply the DST correction (-4) and then note that the hours are really an hour earlier.

Either way gets you the same answer.

 

[Hang 4]

There is no savings time in Zulu. The explanation is confusing. EST is -5, EDT is -4. The FBO opens at the same time locally all year round.

 

[Kodiak]

It does seem to be a strange way of handling the zulu time. As someone said, just using the standard time with any zulu time that has the ‡ following it is the way to do it. My problem was that the study material I am using didn't have any explanation in it as to what the ‡ meant.

 

[midlifeflyer]

It does seem to be a strange way of handling the zulu time. As someone said, just using the standard time with any zulu time that has the ‡ following it is the way to do it. My problem was that the study material I am using didn't have any explanation in it as to what the ‡ meant.

They may have assumed you understood from elsewhere that it is a typographic symbol which says to look elsewhere for the explanation. In this case it's the A/FD legend


We're all familiar with an asterisk. Less well-known is that there are a series of symbols which do the same thing. The ‡ is one of them. Think of them as a form of footnote or endnotes.

Supposedly, there is a proper typographic sequence, but once past the basic * I've seen a lot of variety in actual use. True for FAA materials. There are instrument approach charts where I've seen 3-4 different ones. In the A/FD the ‡ has a uniform meaning.

 

[dtuuri]

A/FD should be revised thus, imo:

"The symbol ‡ indicates that during periods of Daylight Saving Time (DST) effective <Z> hours will be one hour earlier than shown."​

 

[flyingron]

Common non-numeric footnoting is saterisk (*), dagger (†), double dagger (‡), paragraph symbol (¶), section mark (§), parallel rules (||), number sign (#). If more are required, they can be doubled up (**, †, ..).

Dagger some times goes by the name obelisk (or obleus). These are largely out of favor these days in lieu of numeric footnote. Even numeric footnotes are less in favor by several scientific style guides in favor of inline citenation notes with the author's name and the abbreviated year (like [NATALIE, 2019]

 

[midlifeflyer]

A/FD should be revised thus, imo:

"The symbol ‡ indicates that during periods of Daylight Saving Time (DST) effective <Z> hours will be one hour earlier than shown."​

I agree that would be much clearer.

 

[Hang 4]

I wonder why that even needs to be footnoted. Zulu time has no change for DST, so if a time is in Zulu, it's the same time all the time. The LOCAL time changes with DST. Having said that, the language "an hour earlier that shown" sounds like the the facility is open an hour earlier local time, even though it's not. The "UTC-5 (-4DT)" seems all that's needed.

 

[midlifeflyer]

I wonder why that even needs to be footnoted. Zulu time has no change for DST, so if a time is in Zulu, it's the same time all the time. The LOCAL time changes with DST. Having said that, the language "an hour earlier that shown" sounds like the the facility is open an hour earlier local time, even though it's not. The "UTC-5 (-4DT)" seems all that's needed.

Because it is changing the Zulu time. It is not "an hour earlier than shown." It is "subtract one hour from the Zulu times for these services."

Forget the UTC conversion. Think only in terms of Zulu. Pretend the conversion isn't even there*. Here is what it says.

Fuel and svc avbl 1300-0500Z‡​

Here is what it means.

Fuel and other services are available between 1300 and 0500Z. During daylight savings time, fuel and other services are available between 1200Z and 0400Z​

The pilot flying from London to Chicago may not care what time it is locally in Chicago. He does care whether he can refuel for the leg to San Francisco. He looks at his Zulu timepiece and doesn't spend a second of time converting anything from local to Zulu and back again.

I think of the ‡ as part of the essential information in an international format;

*Actually, it's not "there." Here is what a typical entry looks like. And that's without part time tower operations. Notice where the Zulu-local conversion is located and where the ‡ is used. Listing the local conversion is at the top with how close the airport is to the city; nice so you don't have to look elsewhere to figure out whether you will be there for lunch and how far to take the Uber, but is otherwise largely irrelevant. The ‡ is along side the Zulu times for various services. They could have left it out completely since aviation operates on Zulu time.

 

[Matthew]

I always get confused by that conversion factor and have to get a refresher every now and then. Even though I know what the answer is (most of the time), the method to get there is where I get lost.

If there's that (++) sign, you subtract the smaller number (the DST offset) from a smaller number (the Z time adjustment) during DST. Otherwise you subtract the larger number (the STD offset) from a larger number (the Z time without the adjustment). Either way, you get the same answer.

 

[dtuuri]

I wonder why that even needs to be footnoted.

Airports jump one time zone to the east during DST, but their operating times stay the same w/respect to local time. So, an hour closer to Greenwich means "Z" time is an hour less at the same local time. If you jumped time zones all the way to Greenwich instead of just one zone, it would be 08Z to 00Z, same as local time in all the zones.

 

[Hang 4]

@midlifeflyer Your post makes sense. I guess if they said "1 hour earlier UTC", that might have been clearer.

 

[flyingron]

I had a discussion with an FSS guy (back when they still existed). We posited that screw-ups of local to Z time conversions were probably the number one reason filed flight plans don't see to "appear" when they should.

 

[smv]

They could have left it out completely since aviation operates on Zulu time.

...but most of the people with which they deal on the ground do not. The FAA puts that in there to allow the pilot to be able to calculate local time so they can convey their arrival/departure information to mere mortal groundpounders. Passengers, hotel clerks, car rental agents, gumars, etc...

That is my story, anyway....

 

[midlifeflyer]

...but most of the people with which they deal on the ground do not. The FAA puts that in there to allow the pilot to be able to calculate local time so they can convey their arrival/departure information to mere mortal groundpounders. Passengers, hotel clerks, car rental agents, gumars, etc...

That is my story, anyway....

Agreed. That's why it's there. For convenience.

 

[LB 408A]

B and C answers are wrong because they are not within the correct Z time listed (which is required for the supplement). A is correct because at the local times fuel is available is 0900Z to 1100Z. The FAA wants us to know that 0900Z&1000Z is between 0900Z & 1100Z with out being too obvious about it, after all it is a test.