Help with New "Stabilized Approach" Question on Written

eetrojan

eetrojan

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I'm preparing for the IR written (taking it in a week).

In some other thread, Bob Gardner referenced ASA's updates to its Test Prep Books. So, I went to his link and took a look with special interest in the new questions:

http://www.asa2fly.com/FAA-Knowledge-Exams-W22.aspx

According to ASA's update, the knowledge test has a new question, reproduced below, that is based on Figure 250 in the FAA's test book Addendum from 2/14, also reproduced below.

How does one reasonably get answer [c] out of the quoted language in ASA's explanation? In case it helps, it's from pages 4-36 to 4-37 of the Instrument Procedures Handbook.

I don't see anything on the plate, interpreted in light of ASA's explanation, that would get me 1,080 feet MSL.

I know that 1,080 is the MDA, but the bullet items in the explanation say that the approach must be "stabilized " before: (1) descending below 1,000 feet above the airport or TDZE (i.e. before descending below 1,270 [1000+Elev] or 1,268 [1000+TDZE]); or (2) descending below 500 feet above airport elevation (770); or lastly, (3) descending below 500 feet above airport elevation (770) or MDA (1080), whichever is less, meaning 770.

Why the heck are there so many different scenarios?

There's nothing in the explanation about bank angle and 500 AGL.

Is C correct only because A and B are wrong in the sense that 480 fpm is totally random, and therefore obviously wrong?

What are they trying to teach us here?

Thanks for your help!

Figure250_New_Question.jpg


Figure250.jpg
 
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Poor question. For one thing, it does not say whether you're landing straight in or circling. Second, none of the answers matches up with the FAA guidance either way. Third, it doesn't say what the weather conditions are IFR or VFR.

The book answers would be:

  • For straight-in with IFR conditions, less than 1000 ft/min sink rate before descending below 1268 MSL (1000 above TDZE).
  • For straight-in with VFR conditions, less than 1000 ft/min sink rate before descending below 770 MSL (500 above airport elevation).
  • For circling, in the circling maneuver, less than 1000 ft/min sink rate by 770 MSL (500 above the airport elevation, that being lower than the 1080 MDA).
...none of which match the answers provided no matter what the conditions are. So, I think ASA needs to recheck with the FAA on this one.
 
Just looking at the question and answers, my guess is that C is the correct answer because the definition of stabilized approach in use is a general limit, an envelope, and only C presents the the answer in such a format. The other two provide specific values which are not required for, or present in, the definition of "stabilized approach".
 
Ron Levy said:
Poor question.
Click to expand...

That's what I was beginning to think.

Thanks for the recap of the three different scenarios that vary based on conditions and type of approach. I'm going to stuff that in what's left of my brain as less than 1000 fpm sink rate by:

1000 AGL, if IFR straight-in,
500 AGL, if VFR straight-in
500 AGL or MDA, whichever is less, if circling
 
fwiw, I got that question wrong on my written. I hadn't seen it before in the Gleim material and I had the same problem as you, I basically couldn't decipher the question. Perhaps best just to memorize the answer on this one and move on?
 
if you memorize most of the answers to the easy questions you have time and brain power to work out the rest of them - but practically speaking you should have done all of the them at least 4-5x by the time you take the test - just give them the answer they want and move on.
 
comanchepilot said:
if you memorize most of the answers to the easy questions you have time and brain power to work out the rest of them - but practically speaking you should have done all of the them at least 4-5x by the time you take the test - just give them the answer they want and move on.
Click to expand...


That's what they're trying to stop with all of these badly written inane questions, ironically. If they'd just write down the questions instructors and DPEs ask instead of the dippy ones like this one, they'd have something worth asking.
 
Interesting that they would select one of the few remaining non-compliant RNAV/GPS IAPs where the FAF is also the IAF. And, note no "NoPT" on the feeder route from AUG VOR. That is a very obsolete approach procedure.
 
denverpilot said:
That's what they're trying to stop with all of these badly written inane questions, ironically. If they'd just write down the questions instructors and DPEs ask instead of the dippy ones like this one, they'd have something worth asking.
Click to expand...
This is what happens when test questions are written by professional test question writers rather than professional flight instructors.
 
Ron Levy said:
This is what happens when test questions are written by professional test question writers rather than professional flight instructors.
Click to expand...

I think we need to stick with professional test writers. Look at what happens here when a "professional flight instructor" wants to argue page after page over semantics. Now imagine such flight instructors writing test questions....:rolleyes:
 
RotorAndWing said:
I think we need to stick with professional test writers. Look at what happens here when a "professional flight instructor" wants to argue page after page over semantics. Now imagine such flight instructors writing test questions....:rolleyes:
Click to expand...
If the person writing the question understands the semantics, they can write the questions and answers accurately so we can select the correct answer and don't have to guess which is the "best" answer as we do in the posted question. It is the brutalization of the semantics which leads to people using the wrong terms for things, and then the difficulty in explaining/understanding, for example, why actual instrument time is not the same as time spent in IMC or operating under IFR.
 
Ron Levy said:
If the person writing the question understands the semantics, they can write the questions and answers accurately so we can select the correct answer and don't have to guess which is the "best" answer as we do in the posted question.
Click to expand...

Big "IF".

Ron Levy said:
It is the brutalization of the semantics which leads to people using the wrong terms for things, and then the difficulty in explaining/understanding, for example, why actual instrument time is not the same as time spent in IMC or operating under IFR.
Click to expand...

Professional CFI's are just as guilty for that brutalization.
 
RotorAndWing said:
Big "IF".



Professional CFI's are just as guilty for that brutalization.
Click to expand...
Agreed on both points. The person writing the questions must know both how to write good questions generally and understand the material and semantics well enough to write good questions on that specific topic. Unfortunately, the record suggests that it's a lot harder to do that for these tests than whoever's currently in charge of that operation seems to think.
 
Maybe a question they SHOULD ask is can you convert the approach plate info on distance and elevation into a fpm at a given knots? Or convert it into degrees (given a table of tangents).
 
coloradobluesky said:
Maybe a question they SHOULD ask is can you convert the approach plate info on distance and elevation into a fpm at a given knots? Or convert it into degrees (given a table of tangents).
Click to expand...

In a Garmin at least, you get LNAV+V.
 
aterpster said:
In a Garmin at least, you get LNAV+V.
Click to expand...

But that is of no bearing on this test question. This is test taking 101, has nothing to do with the material itself, it's analyzing the question and the given answers and using a process of elimination. First thing you look for is the structure and object. If the terms of the structure, and the objective term in the prospective answer don't match the question, you can eliminate that answer. Second thing you look at is "Can I arrive at this answer with information given?"

Using these two criteria you can 85% most any multiple choice test.
 
coloradobluesky said:
Maybe a question they SHOULD ask is can you convert the approach plate info on distance and elevation into a fpm at a given knots? Or convert it into degrees (given a table of tangents).
Click to expand...
You don't need a "table of tangents", just a calculator (or pencil, paper, and long division) and the gradient/speed/rate table from the Terminal Procedures book, and that's provided already. And there are such questions already in the IR written question bank.
 
aterpster said:
In a Garmin at least, you get LNAV+V.
Click to expand...
You cannot rely on LNAV+V for an approach which meets the FAA's stabilized approach criteria. On too many approaches, LNAV+V will put you in a really nasty situation. Just try it on the NDB or GPS RWY 34 at Cambridge MD (KCGE), for example, and next thing you know you're diving at the runway on about a 600 ft/nm gradient, which is half again the maximum the FAA allows on a straight-in nonprecision approach.
 
Ron Levy said:
Agreed on both points. The person writing the questions must know both how to write good questions generally and understand the material and semantics well enough to write good questions on that specific topic. Unfortunately, the record suggests that it's a lot harder to do that for these tests than whoever's currently in charge of that operation seems to think.
Click to expand...


The question writing chores will be performed by a different group as part of the change to the Airman Certification Standard. In the next batch of questions due next month you will notice that many of the questions we have griped about for years are no longer included.

Bob Gardner
 
register@teamandras.com said:
Is C correct only because A and B are wrong...?
Click to expand...
I'd say yes.

Rule out "...to MDA" because a stabilized approach is "to touchdown".

Rule out "...below 1580 feet" because a stabilized approach might be 500 feet above airport elevation (VFR, circling), but not 500 feet above MDA.

Answer C is correct because a stabilized approach is less than 1000 feet per minute and there is no restriction on bank angles, so 15 degrees seems reasonable.

I think the NTSB feels your pain. They've tried to get the FAA to define "stabilized approach" and the FAA dodged it twice: http://www.ntsb.gov/investigations/...sb.recsearch/Recommendation.aspx?Rec=A-01-069

Here's a good definition from the Instrument PTS resource list (page 6/7 par 9.s.: http://www.faa.gov/documentLibrary/media/Advisory_Circular/ac61-134.pdf

dtuuri
 
Ron Levy said:
You cannot rely on LNAV+V for an approach which meets the FAA's stabilized approach criteria. On too many approaches, LNAV+V will put you in a really nasty situation. Just try it on the NDB or GPS RWY 34 at Cambridge MD (KCGE), for example, and next thing you know you're diving at the runway on about a 600 ft/nm gradient, which is half again the maximum the FAA allows on a straight-in nonprecision approach.
Click to expand...

I understand that quite well.
 
aterpster said:
I understand that quite well.
Click to expand...

I wrote an article in the last century about the possibility of flying into a building more then 250 feet below MDA.

At least today flight inspection is going thumbs down on many VDAs as they are flight inspected. They don't want the FAA helping you fly into the trees.
 
dtuuri said:
Answer C is correct because a stabilized approach is less than 1000 feet per minute and there is no restriction on bank angles, so 15 degrees seems reasonable.
Click to expand...
Answer C is not correct because you must be stabilized at 1000 above TDZE, not MDA, for a straight-in in IFR conditions, i.e., 1268, not 1070. If it's circling, it's lower of MDA or 500 above airport, and that would be 770 MSL. And 1080 MSL is also wrong for a straight-in in VFR conditions (500 above airport, or 770 MSL in this case). So whether it's straight-in or circling (and they forgot to include that in the question), IFR or VFR conditions (which the also forgot to mention), Answer C is wrong per the IPH (the specified reference).
 
aterpster said:
I wrote an article in the last century about the possibility of flying into a building more then 250 feet below MDA.

At least today flight inspection is going thumbs down on many VDAs as they are flight inspected. They don't want the FAA helping you fly into the trees.
Click to expand...
All things considered, I think Garmin did everyone a disservice with LNAV+V -- just too many times it leads you into trouble.
 
If you take 2300 and subtract 1080 you get 1220. Then 1220/5.1 equals 239.2fpm at 60knots (1 nm per minute). At 120 knots you get twice that which is 478.4fpm which is very close to the 480fpm.

So for 120 knots approach speed 480fpm works from 2300' down to 1080 in the 5.1nm horizontal distance.

Maybe that's how they get the 480????
 
Ron Levy said:
This is what happens when test questions are written by professional test question writers rather than professional flight instructors.
Click to expand...

I think you're giving the FAA exam writers too much credit by calling them professional.
 
coloradobluesky said:
If you take 2300 and subtract 1080 you get 1220. Then 1220/5.1 equals 239.2fpm at 60knots (1 nm per minute). At 120 knots you get twice that which is 478.4fpm which is very close to the 480fpm.

So for 120 knots approach speed 480fpm works from 2300' down to 1080 in the 5.1nm horizontal distance.

Maybe that's how they get the 480????
Click to expand...
Maybe it is, but the computations you went through have nothing to do with complying with the guidance quoted from the IPH. Further, they never mentioned a speed in that question, and there's no way to convert a gradient to a descent rate without forward speed.
 
Ron Levy said:
All things considered, I think Garmin did everyone a disservice with LNAV+V -- just too many times it leads you into trouble.
Click to expand...

It really goes to the entire industry and the FAA. It's all about the VDA. Since the FAA got burned on that Lear Jet hitting the trees, flight inspection is nixing quite a few VDAs as they can get to them. No VDA equals no +V.
 
flyingron said:
I think you're giving the FAA exam writers too much credit by calling them professional.
Click to expand...

The exam writers to my understanding are indeed professional test writers. As it was explained to me there is a department with offices in Kansas that when a government office needs a test, they create it, regardless the subject matter. They just take the reference material being tested on and write tests from it.
 
Well, it doesn't say you CAN'T pick a speed that agrees with 480fpm. Which, working with a calculator, is 120.39knots (and it would be groundspeed). So if you flew it at 120.39 knots a descent of 480fpm would work, so answer A would satisfy.

A. 480 fpm to the MDA

It DOESN'T SAY you can't pick your own airspeed to make the answer work.
 
I think maybe I figured out a logical way to get the WRONG answer. (sort of how the test preparers mislead you).

I think C is the answer that will get it scored RIGHT and get you points for your test.
 
Ron Levy said:
Answer C is not correct because you must be stabilized at 1000 above TDZE, not MDA, for a straight-in in IFR conditions, i.e., 1268, not 1070.
Click to expand...
Answer C is a true statement. You're adding conditions uncalled for. It would not be true had they said above touchdown, which is what you're saying, unless they also said below 1000 feet AGL.

dtuuri
 
Is the question assuming a non precision "chop and drop" profile as the correct procedure?
 
Just taking a shot at parsing the question rather than substituting new questions for it. The question is which of the 3 conditions would be a descent rate for a stabilized approach.

In reality, A and B are practically identical. I can't figure out anything about why 1580 is an important altitude for any reason, it feels like a random number. Regardless, there are many descent rates that can be used other than 480 fpm/fpnm.

I believe they're asking you to regurgitate 4.a. from AC-20120-108, which states:

a) Stabilized Approaches. A stabilized approach is a key feature to a safe approach and landing. Operators are encouraged by the FAA and the International Civil Aviation Organization (ICAO) to use the stabilized approach concept to help eliminate CFIT. The stabilized approach concept is characterized by maintaining a stable approach speed, descent rate, vertical flight path, and configuration to the landing touchdown point. Depart the FAF configured for landing and on the proper approach speed, power setting, and flight path before descending below the minimum stabilized approach height; e.g., 1,000 feet above the airport elevation and at a rate of descent no greater than 1,000 feet per minute (fpm), unless specifically briefed. (See AC 120-71.)
Click to expand...

I don't see any specific learning, other than question writers will pull from obscure sources. And that they might not always understand the question they're asking.
 
Exactly, RTFQ and figure out what they are looking for, then look at what information they give you. Look for an answer that fits the question first, then see if the information applies. Here is wherein the knowledge gets tested, if you fall for a distractor, you didn't know it didn't apply.
 
bflynn said:
... I believe they're asking you to regurgitate 4.a. from AC-20120-108, ...
Click to expand...

Thanks for the link. Answer "C" still seems unsupported to me, though, because it says the approach should be stabilized (with a descent rate of less than 1,000 FPM) at no lower than "1,000 feet above the airport elevation," whereas answer "C" talks about 1,080 feet, which is the MDA and is lower than 1,000 feet above the airport elevation.

It may well be a crappy question, but I suspect that the test taker who reported it to Sheppard remembered something a little bit incorrectly.
 
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