So many multiple correct (or none correct) answers

[IO540]

I have just started working through the 7-exam IR set (FAA CPL/IR to JAA PPL/IR).

On a quick look I know about 50% of it straight off. Especially a lot of the aircraft-tech stuff which is easy for any pilot who actually flies something reasonably nontrivial.

And one spots loads of deliberate word play questions, like selecting a standby pitot if your static vent blocks up.

But I am finding lots of questions where there is more than one correct answer, and the multiple answers are equally correct - or at least any inequality in their correctness is aircraft/system-dependent. Especially in avionics, which I happen to know a bit about (been in electronics for 45+ years).

I also see some where none of them are right, or the answer is totally system specific. For example one question is when (in which modes) you see wx info on an EHSI. I have an EHSI (Sandel 3500) in my plane and I can tell ya that it is a totally bollox question.

How come these things have been there for about 10 years (JAA?) and are still there?

Maybe a part of the answer is that nearly everybody doing these exams is a young lad/girl who has no previous knowledge of aviation so they don't spot it, are just happy to pass, and anyway one promptly forgets this stuff because it's obvious that at least 90% (no exxageration) is not relevant to practical flying. But if EASA gets its way and forces a load of existing N-reg pilots to sit the JAA/ EASA exams, a lot more people are going to have a moan.

[The500man]

But I am finding lots of questions where there is more than one correct answer, and the multiple answers are equally correct

This is why most people sign upto a question bank and learn the questions. Even if you read and understand the books, as soon as you start looking at the exam-like questions, you'll easily get a lot wrong simply because they are total nonsense (or atleast I do).

Funnily enough alot of what's been in the books I've read so far hasn't been included in the questions.

Calculating impedance in an AC circuit being a good example of something that I can't imagine ever being useful. Unless of course you get really bored en-route and decide to modify your aircrafts avionics. No doubt all pilots carry the spare parts and tools to do this in their flight bags?

Just be grateful that you only have to do the seven instrument exams and not the whole lot!

[kui2324]

As you are finding out what you have to learn is not necessarily what is real life.

Imagine how I felt in HP&L! Had to really bite my tongue and watch my pencil on several answers cos I knew they were wrong!

Good luck. And definitely use a question bank!

[paco]

The whole question system is an absolute disgrace, which ensures that you can't pass the exams on knowledge alone, which is surely the desired end?

There shouldn't be anything type-sepcific, except perhaps for the 737, which is used as a sample aircraft. Query anything like that straight away.

Phil

[IO540]

There isn't supposed to be anything jet-specific in the 7-exam subset. I checked this specifically.

Yes, the electrical questions are bizzare in their relevance to operating an aircraft. For me they are easy but ......... so pointless! You may as well learn how many goolies a male in a certain species of spider has. And the avionics of anything half modern has moved on since that avionics stuff was written. They consider a KNS80 as state of the art equipment; it has been obsolete at least 10 years.

The IFR nav stuff is like a college trip to the Iron Bridge I did in 1974. It was largely obsolete in operational terms at the time JAA came in 10 years ago. No wonder fresh JAA IR graduates say they can't fly IFR around Europe, and IMHO the system hangs together only because they end up in the RHS with a clued-up old boy in the LHS.

There are new exams due June 2011, slightly (10-15%) reduced, but they are about 3 years overdue and the date may slip. Anybody sitting the current exams must pass the last one before March 2012 otherwise - it is officially stated though I can hardly believe this would actually happen - all existing passes will be forfeited.

[paco]

The AGK stuff is not in the new syllabus for the IR, except for automatic flight control. At least according to the LOs I have in front of me. In UK, you should be able to take the new exams starting from June.

Phil

[IO540]

I wonder if the question bank for the new papers will also come out in June.

If not, there is no point at all in waiting for the new papers, because the old ones with the QB are going to be a lot easier than any new ones (with maybe a 10-20% reduction) but with no QB.

Working through this stuff, at least 95% of it bears no relation to practical IFR flight, so one has to learn it in a rather sterile manner. I am now on radar pulse repetition rates... great stuff but totally utterly irrelevant

[paco]

I believe the new questions will be there as well......

Phil

[Golf Juliet Bravo]

Question Banks A Joke.

Hi

I read with interest your most recent post questioning the quality of the current IR question banks, let me tell you my story. I’ve been totally passionate about flying for 40 years, I have flown 2000 hours and have extensive experience flying a number of types of aeroplanes I’m am also IR and aerobatics qualified. I recently embarked on the CPL distance learning course because I was keen to instruct. My distance learning experience has been a disappointing one, the course is largely irrelevant to those who want to instruct and the quality of the questions are simply appalling. I’ve seen many questions which are factually incorrect, questions designed to deliberately catch the candidate out and so called correct answers that are clearly incorrect.

I recently stuck 2 fingers up at the distance learning course, the question that broke the camels back is illustrated below in an email exchange between my distance learning provider and I where several of he answers were correct, the school subsequently admitted I was right. The question banks are littered with crap.

Dear Sir
Thanks for taking the time to get back to me on this. Without wishing to be pedantic the explanation given does not hold water within the context of the question.

Q12: Lift is generated when?

(a) A mass of air is accelerated downward.

Downward in what sense, vertically downward? That's what the option implies. If we mean the downward acceleration of air over the upper surface of a wing then let’s say that in the option and limit the guess work! It’s not a downward acceleration of air at all but merely an acceleration of air ACROSS the upper surface of the aerofoil causing the reduced pressure causing the pressure differential resulting in Lift.

(b) The shape of the aerofoil is slightly cambered.

You say that a cambered aerofoil by itself does not generate lift!! This is news to me and indeed contradicts your own notes:

Page 2-6 "Effect Of Angle Of Attack On Pressure Distribution"

Description of a conventionally cambered aerofoil: "Such an aerofoil produces lift at zero degrees angle of attack because the aerofoil (should read airflow) over the upper surface, with its greater curvature is accelerated more than over the lower surface creating a pressure differential and thus positive lift is generated". Yes indeed lift is generated when an aerofoil is slightly cambered. Right answer.

(c) An aerofoil is placed in a high velocity airstream: Of course lift is generated in this circumstance, I refer again to the quote above from your own notes. Right answer.

(d) A mass of air is retarded. Wrong answer, no argument.


I'm sure we could debate the detail further but my point is ask clear questions and give clear options, there are too many examples like the above throughout the assessed exercises and the question bank which add little or no value to the student.

Regretfully I shall not be continuing with the CPL course.

Regards

It’s my opinion that these theory courses are a money making circus for the course providers and the caa, generating school boy/girl flying academics but not real pilots.

Good luck and best wishes.

[Alex Whittingham]

Regarding your first question, Q12,which is a CQB question, there are two explanations for lift, one uses Bernoulli and pressure distribution to justify the lift produced, the other shows that an airfoil deflects air downwards and the reaction to that downwards force is what we perceive as lift. Both explanations have their plus and minus points.

I can't really comment on the rest of your correspondence without seeing the questions.

[Edited to say 'Doh! I've just realised that it was all one question'. The explanations of the other incorrect answers below are correct, though.]

[EK4457]

Golf Juliet Bravo, whilst I totally and utterly agree with your opinion on the state of the JAA/EASA question bank, I'm afraid you made a bit of an arse of your Q12.

Q12: Lift is generated when?

(a) A mass of air is accelerated downward.

This is the most correct answer. This answer is ALWAYS true.

Despite what anyone has ever said to you, lift is purely a reaction to the deflection of air downwards. How an aerofoil does this is pretty complicated and many pilots get this all wrong. Not your fault, you were probably told a load of rubbish by your instructor.

Firstly, the difference in pressure between the upper and lower surfaces is a RESULT of the generated lift and does NOT produce it. Infact, this is the cause of your induced drag via wing tip vorticies. If you could somehow deflect the air downwards without getting any difference in pressure then you would have a damn near perfect aerofoil.

Airflow that runs along the bottom of the aerofoil is deflected down in a pretty simple fashion.

However, the upper surface is where pilots get it all wrong. The viscosity of air means that, for low angles of attack, it sticks to the surface with high inertia and low internal drag. This boundary layer is faster than the free stream air because it is laminar (flows in low drag layers a cm or so thick). It needs to be fast to stick, and it needs to stick so that it can leave the trailing edge in a downwards direction.

The fact that the increase in velocity gives an increase in dynamic pressure and thus a decrease in static pressure is purely consequential.

There is much more to it thant that but you get the general idea.

(b) The shape of the aerofoil is slightly cambered.

This is NOT always true. You will not produce lift with a negative or too high AOA (stall).

Interestingly, you do NOT need camber to produce lift. You can have a symmetrical aerofoil produce lift as long as it has a positive angle of attack and enough airflow. In fact if you take a sheet of glass, give it a positive AOA and enough airflow, it too will produce lift (just with a low L/D ratio). Certainly not cambered though!

To take it further, the C152 aerobat has a cambered wing but can fly upside down no problemo. You can even produce lift with negative camber! All you have to do is push enough air downwards for the least drag penalty.


(c) An aerofoil is placed in a high velocity airstream

Again, you can have a negative AOA, or stall (too high AOA) and not produce lift regardless of IAS. Not ALWAYS true.

(d) A mass of air is retarded.

Standard ridiculous answer.

You can usually get round these Qs by asking 'which is always correct?', 'which is most correct?' or 'which is least wrong?'.

But the courses and the questions are utterly insane and not fit for purpose.

EK

[IO540]

there are two explanations for lift, one uses Bernoulli and pressure distribution to justify the lift produced, the other shows that an airfoil deflects air downwards and the reaction to that downwards force is what we perceive as lift. Both explanations have their plus and minus points.

Both are equally true. They have to be.

Bernoulli derives from Newtonian mechanics. The reason Bernoulli is used in this case is because it simplifies the calcs for fluids.

For a wing to generate lift, it must redirect the airflow in a downwards direction. This cannot be done without a pressure difference being created between the top and bottom, and that cannot be done without the airflow on the top being faster than the airflow on the bottom. It's all the same thing.

The problem with those questions is that the terminology is ambiguous and that makes them meaningless. I recall one question from the PPL which was something like which of the two types of drag (induced and parasitic) increases/decreases with speed. The obvious answer is they both increase. The absolute values of both must increase. But that is the wrong answer...

The IR exam material is mostly bull, put in for a laugh. Like the questions on Glonass. But one could go on and on. If one wanted questions that test knowledge without reliance on having read a specific prescribed book (to get the terms right) one would remove about 1/3 right away. If one tested knowledge relevant to aviation one would remove about 90%.

If you could somehow deflect the air downwards without getting any difference in pressure then you would have a damn near perfect aerofoil.

That is about as physically possible as a single magnetic pole

[EK4457]

It's certainly up there with the 100% efficient heat engine, perpetual motion and travelling at the speed of light!

[keith williams]

This thread illustrates what is arguably the greatest single problem aflicting the JAR CQB system.

No, I do not mean the poorly worded questions. There are quite a few of those but they are not the single greatest problem.

The single greatest problem is that having been told about the poorly worded questions, a large number of students start with the assumption that if they cannot answer a question, then that question must be defective. This leads to the situation where students devote all of their efforts to convincing themselves that the question is defective, instead of simply attempting to find the best answer.

The post by Golf Juliet Bravo is an example of this. The post by EK4457 provides a much more productive approach.

[paco]

One question springs to mind - why are you doing POF questions on an IR exam? Air is accelerated downwards, as you can prove by flying over a cornfield (read Stick & Rudder). However, Bernoulli is not the complete answer either, as your average Cessa would likely have to do more than 400 knots to produce the effects required. NASA brings in the question of wake vortices that are descending in the region of the root of the aerofoil, but let's not forget the Coanda effect which, interestingly, Transport Canada has introduced into its syllabus.

I like to point out that the aerofoil creates a cocoon of lower pressure air around itself, less on the top than underneath. Atmospheric pressure (which acts on all surfaces) then acts on that cocoon to push the aerofoil upwards. My gran understands that one

You have to suspend belief with the JAA questions - I have come across many engineers who point out that certain things are wrong, but they are missing the point. You have to go for the least wrong answer.

It's a shame you had to dispense with the learning provider, because it isn't really their fault. They are torn between teaching you the truth and what the exams want.

And I hear you about the students, Keith

Phil

[IO540]

why are you doing POF questions on an IR exam?

I think that was the other poster who was doing a CPL (no IR).

My JAA IR stuff doesn't have this.

[paco]

I stand connected - not enough blood in the coffee stream!

Phil

[tow1709]

I have signed up to one the well known internet-hosted question banks. I have found it quite useful, but "failed" in Air Law because I did not know the minimum height of the aircraft registration lettering on the fuselage.

It is not something I have ever checked on my preflight walk-around, but perhaps I should take a tape measure in future!

Returning to earlier posts on the subject of lift, the quoted question assumes we are talking about a wing generating lift in opposition to the way gravity is acting. Aerodynamic lift can be generated in any direction - not just downwards - rudder/tail fin is an example. With pedant's hat on, I could have been tempted to reject such an answer, thinking they were trying to catch me out.

[IO540]

Which internet bank did you use?

I have been offered one (didn't get the name of it) which is supposedly £10 per month, and it has had the ATPL questions stripped out of the 7-exam version.

[keith williams]

I have found it quite useful, but "failed" in Air Law because I did not know the minimum height of the aircraft registration lettering on the fuselage.

The pass mark is 75%.

Did you really lose 26% of the marks because you didn't know the minimum height of the registration lettering?

Or did you not know enough about air law.