Ground elevation on a sectional chart

[samd012]

I am studying for the 107 and have a question which I can not seem to grasp. On the attached chart
The terrain elevation of the light tan area between Minot (area 1) and Audubon Lake (area 2) varies from how many feet to how many feet.
I am not just looking for the answer but an explanation of how you came up with it.

 

[BorisTheSpider]

Looking at the obstacle heights, you can say 2345-226=2119ft elevation near (1) and 2524-303=2221ft near (2).

So about 102ft.

That said, I didn't look to check the other obstacles didn't indicate a bigger terrain elevation difference, and I'm not familiar with FAA charts, so you shouldn't take my advice over that of someone else who does know FAA land and actually has a 107

 

[samd012]

Looking at the obstacle heights, you can say 2345-226=2119ft elevation near (1) and 2524-303=2221ft near (2).

So about 102ft.

That said, I didn't look to check the other obstacles didn't indicate a bigger terrain elevation difference, and I'm not familiar with FAA charts, so you shouldn't take my advice over that of someone else who does know FAA land and actually has a 107

I appreciate the input but that is not even one of the 3 options. I thought I was pretty good with sectionals overall but this one has me stumped.

 

[ascension]

What are the options?
There are a few ways to determine terrain elevations on sectionals.
The most basic is the color of the area. In your example, the tan area indicates a max terrain between 2000 and 3000 feet, while the green area by the lake is 1000-2000.

In addition, there are sometimes spot elevations indicated by a a dot in front of the elevation, like .2160, which would indicate a spot elevation of 2160' MSL

And you can determine the ground elevation at an obstacle by subtracting the number in parenthesis from the top number which is obstacle height at top in feet MSL.

 

[samd012]

What are the options?
There are a few ways to determine terrain elevations on sectionals.
The most basic is the color of the area. In your example, the tan area indicates a max terrain between 2000 and 3000 feet, while the green area by the lake is 1000-2000.

In addition, there are sometimes spot elevations indicated by a a dot in front of the elevation, like .2160, which would indicate a spot elevation of 2160' MSL

And you can determine the ground elevation at an obstacle by subtracting the number in parenthesis from the top number which is obstacle height at top in feet MSL.

Choices are:

2,000 feet to 2,500 feet MSL
2,000 feet to 2,700 feet MSL
sea level to 2,000 feet MSL

 

[ascension]

Its a little tough to be certain because the scale of the attachment is smaller than the actual chart, and hard to read, but I would choose 2000-2700.
The tan area in area 1 indicates 2000-3000.
The green area by the lake indicates 1000-2000, but they don't specifically define what the geographic limits are in their description, and there is a 2800' max terrain symbol in the grid just near the lake, indicating 2700 rounded up.

 

[samd012]

Its a little tough to be certain because the scale of the attachment is smaller than the actual chart, and hard to read, but I would choose 2000-2700.
The tan area in area 1 indicates 2000-3000.
The green area by the lake indicates 1000-2000, but they don't specifically define what the geographic limits are in their description, and there is a 2800' max terrain symbol in the grid just near the lake, indicating 2700 rounded up.

I appreciate the feedback. Unfortunately I am still a bit lost on this one. The test is saying 2000-2500 but I do not know why. I see your explanation and would tend to agree. I think it is a ridiculous question and hopefully I do not get something like it on the test. I am planning on going in the next week.

 

[ElGuapo]

I appreciate the feedback. Unfortunately I am still a bit lost on this one. The test is saying 2000-2500 but I do not know why. I see your explanation and would tend to agree. I think it is a ridiculous question and hopefully I do not get something like it on the test. I am planning on going in the next week.

I will take a stab at it..

The terrain elevation of Adubon Lake is 2267 MSL, 350 AGL therefore 2267 - 350 = 2,450
The terrain elevation of the TAN area ( the highest point in the tan area ) is 2879 MSL, 700 AGL, therefore 2,879 - 700 = 2,179

The terrain elevation between Minot and Audubon Lake varies from 2,000 ft to 2,500 MSL.

Correct answer is 2,000 ft to 2,500 ft

Also when you take your part 107 pay special attention to the wording on the test. In this particular particular case the operative word is "the terrain elevation of the light tan area ", having said that, the highest point in the "light tan area" is 2879 (700).

When I took mine I got couple of questions wrong because I did not take the time read the question carefully. The questions were something "What is not a concern during something (can't remember what it was), I knew the answer, however the key word of the question was the word "not" so I answered the question as if it read "What is a concern".

 

[samd012]

I will take a stab at it..

The terrain elevation of Adubon Lake is 2267 MSL, 350 AGL therefore 2267 - 350 = 2,450
The terrain elevation of the TAN area ( the highest point in the tan area ) is 2879 MSL, 700 AGL, therefore 2,879 - 700 = 2,179

The correct answer is 2,000 ft to 2,500 MSL

Also when you take your part 107 pay special attention to the wording on the test. In this particular particular case the operative word is "the terrain elevation of the light tan area ", having said that, the highest point in the "tan area" is 2879 (700).

When I took mine I got couple of questions wrong because I did not take the time read the question carefully. The questions were something "What is not a concern during something (can't remember what it was), I knew the answer, however the key word of the question was the word "not" so I answered the question as if it read "What is a concern".

You lost me, lol. For Audobon lake the tower is 2267-350 which is not 2450. That would put AGL at 1917. Or did I miss something?

I just scheduled the test for Sunday. I am not going to let one question I can't figure out discourage me I believe I have a pretty good grasp on the content. I have taken Microsoft certification tests before and know you have to read every word. I have seen where they have taken publicly known test questions and changed one or two words and it changes the answer but if you have read the question so many times while studying you jump to the answer you studied not what was being asked.
How much detail do they give you on what you got wrong???

Also the full sectional is here, I did miss the legend down the bottom right when I first tried to figure it all out.

 

[ElGuapo]

Well, they change the wording in their tests.

At the end of the test they tell you on the spot if you passed, and your passing score. They confiscate the scratch paper you used during the test. They also ask you if you want to see the questions you missed but they also tell you that you are not allowed to write anything down.
They took me to the station I was using and showed the questions I missed and the correct answers.

I tested myself with the practice test on 3dr's website and that was a good feel of what is coming on the test.
My test had a lot of questions on navigational charts specially identify air space by the color of the rings and altitude. I also had a few questions on TAF and KMEM. Couple of weather questions.

As for the above I will take a look at the sectional when I get home, Lol.

 

[Seansy]

So I know this is an old thread but thought I'd provide some insight in case any one else has the same question. I drew a straight (imaginary) line between Minot and Audubon. There is a tower on the edge of the tan section near Minot with 3147 (1081) elevation, so to calculate the terrain elevation at that point you take 3147-1081= 2,066, or approximately 2,000 MSL. Around the Midway point you see the text "max" with the value 2508 UC. I take the 2508 as the terrain elevation since the tower is still under Construction, hence no value in parenthesis. Therefore the terrain elevation varies from 2000-2500.

 

[HRS]

So I know this is an old thread but thought I'd provide some insight in case any one else has the same question. I drew a straight (imaginary) line between Minot and Audubon. There is a tower on the edge of the tan section near Minot with 3147 (1081) elevation, so to calculate the terrain elevation at that point you take 3147-1081= 2,066, or approximately 2,000 MSL. Around the Midway point you see the text "max" with the value 2508 UC. I take the 2508 as the terrain elevation since the tower is still under Construction, hence no value in parenthesis. Therefore the terrain elevation varies from 2000-2500.

I'm also very puzzled by this question, and your explanation is the only one that comes close to hitting the "2500" number. But, the symbol for that under-contruction tower has it as "Below 1000 ft AGL" (and the nearby completed tower is at 2524-303 = 2221 feet terrain elevation) so I don't think the 2508 number would (logically) denote the terrain elevation there (unless it was an eight-foot tower!).

So, I'm beginning to think this is just a botched question/answer combination.

 

[MajorNadds]

I'm new to the forum and studying for my 107 to be able to do powerplant work inside and out for my utility job. I'm glad I ran across others with this question. I spent many years writing nuclear plant operator questions, and sometimes the key is to simplify. I didn't look for measurements outside the tan area like the question asked. I got this one right partly by looking at the legend. The lowest elevation of the tan is 2000, so there is a good basis for that being in the right answer. There is also a measurement just above garrison in the tan 2216 (265) =1951 or ~2000.
If they had offered 2000-3000 I would have bit based on the legend. They are saying tan is 2000-3000 and the question is about terrain, not obstacles, but it didn't offer that.
I found the under construction or unverified (UC) obstacle about mid-way between the two points at 2507 MSL and went with it since I had nothing else to go on that was close to an answer, and the UC windmills North of that would have been a bigger rounding error to go with 2000-2700. That's how I got there right or wrong. When I was training operators for national exams I would include head scratcher questions to force time management on the test.

 

[golfpilot]

Everything on this map is well above sea-level so you can rule that out. And if you look at all marked obstacles above 2500, they are all very tall obstacles, ruling 2700 out. making 2000-2500 the answer

 

[MajorNadds]

look here at the border of the tan and green right on the flight path. Also, if the tower is UC, then its MSL, correct?

 

[orpilot42]

This is from the FAA's Aeronautical Chart User's Guide https://www.faa.gov/air_traffic/fli...ts/aero_guide/media/editions/cug-complete.pdf
It covers all of the FAA charts (VFR as well as IFR). Lots of information.

 

[TT777]

I'm new, as of today and I'm taking my test tomorrow morning. I came across this question on the 3DR site and was puzzled.

I think the answer is two-fold. Yes, the tan areas are between 2000 and 3000 feet, but there are Maximum Elevation Figures (Big Number next to little number - in hundreds) in each map quadrant that detail how low one can safely fly without hitting anything that's on the ground.

So the Tan Area has an elevation of anywhere between 2000 and 3000 MSL, and the MEF in those two quadrants is 28(00) feet MSL.

The way they determine the MEF is by measuring the height of the highest obstacle, rounding it up to the next hundred feet, and then adding another hundred feet.

So tan = 2000 to 3000 feet

But map explains that the highest thing in that quad is at -2800 feet.

 

[flockshot]

I'm new, as of today and I'm taking my test tomorrow morning. I came across this question on the 3DR site and was puzzled.

I think the answer is two-fold. Yes, the tan areas are between 2000 and 3000 feet, but there are Maximum Elevation Figures (Big Number next to little number - in hundreds) in each map quadrant that detail how low one can safely fly without hitting anything that's on the ground.

So the Tan Area has an elevation of anywhere between 2000 and 3000 MSL, and the MEF in those two quadrants is 28(00) feet MSL.

The way they determine the MEF is by measuring the height of the highest obstacle, rounding it up to the next hundred feet, and then adding another hundred feet.

So tan = 2000 to 3000 feet

But map explains that the highest thing in that quad is at -2800 feet.

I think this question is intentionally vague. If you have just a couple test questions that trick you up, I say memorize the answer and move on.

 

[TT777]

I think this question is intentionally vague. If you have just a couple test questions that trick you up, I say memorize the answer and move on.

Yeah, I'm passing the prep exams with 98% scores consistently. I'm not too worried... But I do wish someone could explain how one would quickly get to the correct answer.

I've committed this one to memory...

 

[flockshot]

Yeah, I'm passing the prep exams with 98% scores consistently. I'm not too worried... But I do wish someone could explain how one would quickly get to the correct answer.

I've committed this one to memory...

Per the dictionary:
Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface.
So we are talking about the ground only.