A/C general exam (oil by-pass question??)
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A/C general exam (oil by-pass question??)
Hi
Been working through the confuser again for my A/C general exam and come across a question which I'm not 100% sure about. The question is: "The valve which allows oil to either flow through or bye-pass a serviceable engine oil cooler is":
A - pressure activated
B - manually activated
C - pneumatically activated
D - temperature activated
I intially thought it was A (pressure activated) but apparently it is D (temperature activated)? I also seem to remember reading somewhere about this very same answer in the PPL confuser being wrong? Would appreciate your views on this as I have an impending exam!
Thanks!
Been working through the confuser again for my A/C general exam and come across a question which I'm not 100% sure about. The question is: "The valve which allows oil to either flow through or bye-pass a serviceable engine oil cooler is":
A - pressure activated
B - manually activated
C - pneumatically activated
D - temperature activated
I intially thought it was A (pressure activated) but apparently it is D (temperature activated)? I also seem to remember reading somewhere about this very same answer in the PPL confuser being wrong? Would appreciate your views on this as I have an impending exam!
Thanks!
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The oil cooler cools the oil. But if the oil is already cool (because the engine is not properly warmed up) you don't want it to flow through the cooler. That's what the bypass is for. So it has to be temperature activated.
What you're probably thinking about is what happens when the oil cooler is blocked. Then you need a pressure-activated bypass. But in this case the question is about a serviceable cooler.
What you're probably thinking about is what happens when the oil cooler is blocked. Then you need a pressure-activated bypass. But in this case the question is about a serviceable cooler.
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I agree it should be "temperature" but a lot of CAA questions are ambiguous. One needs to be really careful. Simply knowing the truth (from e.g. experience) may not help 
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It is a fact that examiners who set exam questions don't sometimes know as much about the subject they are examining than some candidates sitting the paper. Such expert candidates have to bear this in mind and become familiar with the answer that the examiner expects to be given despite the expert candidate knowing that this is not necessarily the correct one! Such expert candidates need to study textbooks written at the appropriate level and sample questions to establish what they are "supposed" to know about their specialist subject.
P.P.
P.P.
The exams were written on the assumption you read TT.
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The question as posted may (or may not) have been in an examination paper when the Confuser was written, but it is not in any of the papers now (unless it has been reintroduced very recently)
If it ever was a real question, then it was probably removed following complaints form candidates. The CAA examiners are far too busy with the errors in the ATPL question bank to spend much time looking for errors in the PPL papers.
A similar current question in a current paper is as follows:
Should the oil cooler in the engine become blocked in flight, a by-pass valve allows the oil to by-pass the cooler. This by-pass valve is:
(a) temperature dependent.
(b) pressure dependent.
(c) manually selected.
(d) held open by spring pressure.
The correct answer is option b.
This question is better than the one originally posted in that it sets up a scenario in which the oil should already be warmed up, but the cooler becomes blocked. In these circumstances the pressure operated by-pass valve will open.
There is however a possibility that some candidates might interpret the scenario as one of "Oil Cooler Coring" in which very cold air over-cools the oil, making it too thick to flow freely through the filter. Based on this interpretation the candidate would then select option a.
It is important to remember that errors and ambiguities in the papers will be corrected only if examiners are made aware of them.
If you see an ambiguous question in your exam make a complaint to your examiner. He/she can then take the matter up with the CAA.
If it ever was a real question, then it was probably removed following complaints form candidates. The CAA examiners are far too busy with the errors in the ATPL question bank to spend much time looking for errors in the PPL papers.
A similar current question in a current paper is as follows:
Should the oil cooler in the engine become blocked in flight, a by-pass valve allows the oil to by-pass the cooler. This by-pass valve is:
(a) temperature dependent.
(b) pressure dependent.
(c) manually selected.
(d) held open by spring pressure.
The correct answer is option b.
This question is better than the one originally posted in that it sets up a scenario in which the oil should already be warmed up, but the cooler becomes blocked. In these circumstances the pressure operated by-pass valve will open.
There is however a possibility that some candidates might interpret the scenario as one of "Oil Cooler Coring" in which very cold air over-cools the oil, making it too thick to flow freely through the filter. Based on this interpretation the candidate would then select option a.
It is important to remember that errors and ambiguities in the papers will be corrected only if examiners are made aware of them.
If you see an ambiguous question in your exam make a complaint to your examiner. He/she can then take the matter up with the CAA.
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This question is better than the one originally posted in that it sets up a scenario in which the oil should already be warmed up
but this can be surmised only from the words "in flight" which is IMHO a nasty trick to play on somebody.
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I agree that even the new question is less than perfect. But it is certainly better than the one in the original post in this thread.
As I have said, some candidates might interpret it as an oil cooler coring problem and select the wrong answer. This problem could be eliminated quite simply by the CAA adding the words "oil temperature within normal in flight limits" or "ambient air temperature 20 degrees C" (or some similar temperature that would eliminate oil cooler coring).
But this thread illustrates two points of wider significance.
The first point is that problem questions will not be eliminated by waiting until the CAA stumble across them. Local PPL examiners need to look very carefully at all of the exam papers and make the CAA aware of all of the dubious questions. Candidates taking the exams should then make their local examiners aware of any dubious questions that appear in their exam papers.
The second point is that the Confuser is long out of date and contains some dubious questions that are not in the real exam papers. But people who passed their exams long ago when the Confuser was the only option and was probably more relevant, continue to advise new PPL Students to use the Confuser.
VW-Nutter started this thread because using the Confuser has done exactly what is says on the tin.... CONFUSED him/her.
As I have said, some candidates might interpret it as an oil cooler coring problem and select the wrong answer. This problem could be eliminated quite simply by the CAA adding the words "oil temperature within normal in flight limits" or "ambient air temperature 20 degrees C" (or some similar temperature that would eliminate oil cooler coring).
But this thread illustrates two points of wider significance.
The first point is that problem questions will not be eliminated by waiting until the CAA stumble across them. Local PPL examiners need to look very carefully at all of the exam papers and make the CAA aware of all of the dubious questions. Candidates taking the exams should then make their local examiners aware of any dubious questions that appear in their exam papers.
The second point is that the Confuser is long out of date and contains some dubious questions that are not in the real exam papers. But people who passed their exams long ago when the Confuser was the only option and was probably more relevant, continue to advise new PPL Students to use the Confuser.
VW-Nutter started this thread because using the Confuser has done exactly what is says on the tin.... CONFUSED him/her.
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Questions
I have to agree with P Pilcher about the way the exam questions are set.
I was lucky enough to be exempt most of the CAA ATPL technical questions due to holding an Engineers Licence (with CRS approval for BAe 1-11 B737 & A320). When asked to help a few guys on the ATPL course with the Hydraulic exam prep I found that all the stock answers for a modern aircraft were wrong................. In short if I had taken the exam I would have failed it.
The exam seemed to be frozen in the DC-3 era as I suspect was the CAA at the time!
This leaves me with the opinion that the Pilot exams have very little to do with knowing much about the practical side if the subject.
I was lucky enough to be exempt most of the CAA ATPL technical questions due to holding an Engineers Licence (with CRS approval for BAe 1-11 B737 & A320). When asked to help a few guys on the ATPL course with the Hydraulic exam prep I found that all the stock answers for a modern aircraft were wrong................. In short if I had taken the exam I would have failed it.
The exam seemed to be frozen in the DC-3 era as I suspect was the CAA at the time!
This leaves me with the opinion that the Pilot exams have very little to do with knowing much about the practical side if the subject.
Avoid imitations
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A good piece of advice given to me years ago, regarding CAA exams.....
After each question, imagine the words "which of the following answers is least wrong?"
It usually works!
I complained once about some questions in a helicopter tech exam after I failed the paper by one or two percent. Some of the "correct" exam answers referred to switch positions which did not exist on the aircraft! The chief engineer, who also flew part-time, failed the same paper five (yes five!) times then apparently gave up in disgust...
The person setting that paper obviously had no experience of the aircraft (it was a new type in the country and we were the only operators).
After each question, imagine the words "which of the following answers is least wrong?"
It usually works!
I complained once about some questions in a helicopter tech exam after I failed the paper by one or two percent. Some of the "correct" exam answers referred to switch positions which did not exist on the aircraft! The chief engineer, who also flew part-time, failed the same paper five (yes five!) times then apparently gave up in disgust...
The person setting that paper obviously had no experience of the aircraft (it was a new type in the country and we were the only operators).
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A while ago I saw some training material for the CAA LAME exams which a friend of mine was sitting. The bits about electrics and electronics were total bollox... the person who wrote the questions had zero understanding of the subject.
When I was in university I took a statistics course. We all had to do a project and a friend chose to answer the question whether choosing "C" or the longest answer, if it was not "C", was most likely to result in choosing the correct. response on multiple choice exams. After analysing a bunch of old exams he delivered statistical proof that this strategy was more likely to give you a right answer than a random choice. I use this strategy on exams when I have absolutely no idea of the answer.
Given the comments here I think the problem demonstrated is that multi-guess exams are inherently poor in determining a candidates true understanding of a subject.
This is due in part to poor questions and/or answers, to the nature of examinations that force a person to use another persons words, and an examination system that allows for 'statistical' answers such as BPF suggests.
Unfortunately it appears it's not a UK-only phenomenon, as I live some 12,000 miles away. I had reason to expect a 100% pass in CPL Tech, given my 'other' live(s). Answering a question with its fundamentally correct (or least incorrect!) answer wasn't the right thing to do when explaining how a moving-coil meter works apparently. They were clearly looking for something, er, 'higher level' shall we say. CAA (or at least their designated examiners in this case)) had no reason to know I could probably have written a small book on the subject - without needing to research - and so marked me wrong when in fact I was definately correct. Actually to be more accurate; in answering as I did I was using a somewhat deeper level knowledge of the subject than was expected in most candiates. As such there were two 'correct' answers, one explaining the fundamental mechanism, one the mechanism itself more or less. To me, in explaining the operation of something, you get the fundamentals correct first before moving to the next level, hence why I answered that way and probably why I was 'wrong', the examiner may not even have realised the flaw - confirming P.Pilcher's thesis.
Incidentaly this wasn't the only case of a 'bad' Q & A(s) in this exam but it's the only one I can specifically remember at this point. There were also some others that I really did wonder why a pilot should need to know - an engineer perhaps but not someone driving an aircraft. Once again an opportunity lost to examine something that mattered in that particular context...
P.
This is due in part to poor questions and/or answers, to the nature of examinations that force a person to use another persons words, and an examination system that allows for 'statistical' answers such as BPF suggests.
Unfortunately it appears it's not a UK-only phenomenon, as I live some 12,000 miles away. I had reason to expect a 100% pass in CPL Tech, given my 'other' live(s). Answering a question with its fundamentally correct (or least incorrect!) answer wasn't the right thing to do when explaining how a moving-coil meter works apparently. They were clearly looking for something, er, 'higher level' shall we say. CAA (or at least their designated examiners in this case)) had no reason to know I could probably have written a small book on the subject - without needing to research - and so marked me wrong when in fact I was definately correct. Actually to be more accurate; in answering as I did I was using a somewhat deeper level knowledge of the subject than was expected in most candiates. As such there were two 'correct' answers, one explaining the fundamental mechanism, one the mechanism itself more or less. To me, in explaining the operation of something, you get the fundamentals correct first before moving to the next level, hence why I answered that way and probably why I was 'wrong', the examiner may not even have realised the flaw - confirming P.Pilcher's thesis.
Incidentaly this wasn't the only case of a 'bad' Q & A(s) in this exam but it's the only one I can specifically remember at this point. There were also some others that I really did wonder why a pilot should need to know - an engineer perhaps but not someone driving an aircraft. Once again an opportunity lost to examine something that mattered in that particular context...
P.
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This problem does not only occurr in aviation. When I was writing my first response, I was mindful of a very old university friend who was a very talented and accomplished musician who was reading for his M.Mus degree at the time. He was also a very accomplished pianist and had been encouraged to attempt to obtain the top piano playing qualification - the L.R.A.M (licensciate of the Royal Academy of Music). As a skilled composer, he was used to doing musical composition things way above the requirements of the theory papers for this qualification, however, being aware of the fact that he could probably do more than his RAM examiners, was having to re-learn the simpler exercises in these fields so that he would be able to satisfy them!
P.P.
P.P.
One of the problems with PPL exams is that the person setting them has in most cases no relevant experience of teaching for, or examining candidates for a PPL. They have in the past been experienced theoretical knowledge instructors at a more advanced level. It is therefore quite difficult to set questions at a lower level that they are not familiar with. As the last CAA ground examiner is about to retire, and not be replaced, they are left with zero expertise in the field of PPL exams!
The biggest problem I have as an Instructor is relating the theory to the practice. The topic starter question has very little relavance to the operation of a light aircraft.
I want my students to understand what the major parts of the engine lubricating system do, but more importantly understanding function in the context of what is a normal indication of the oil temp/press guage and what is not.
So for example on a cool day we expect the engine oil pressure to intially be near the maximum because the oil is cold and thick. As the engine runs we expect to see the oil temperature rise and the engine oil pressure to drop to the mid range as the oil warms as well understanding that idle oil pressure will be lower than runup and higher RPM operation. In other words I expect the student to be aware of the connection between oil temperature and pressure and RPM. So for example they would know in a hot engine that idle oil pressure in the yellow (low) range is normal but the same indication during a runup (or worse inflight) would be immediate grounds to terminate the flight.
I also review the expected engine guage indications that one would see for the likely emergencies of low oil quantity, oil pump failure, congeled oil cooler, and an inappropriatly bypassing oil cooler.
Finally I emphasize the importance of monitoring guage trends. It is not good enough to say the guage is "in the green" the student must be monitoring the value ( or the relative needle position for those horriblle Cessna/Piper guages with no numbers
). So for example iif the oil pressure in cruise started at the high end of the green arc but is now at the low end of the green arc it is time to starting thinking about what would cuase this and understanding this could be an early warning of an engine failure... even though the oil pressure is still "in the green".
I want my students to understand what the major parts of the engine lubricating system do, but more importantly understanding function in the context of what is a normal indication of the oil temp/press guage and what is not.
So for example on a cool day we expect the engine oil pressure to intially be near the maximum because the oil is cold and thick. As the engine runs we expect to see the oil temperature rise and the engine oil pressure to drop to the mid range as the oil warms as well understanding that idle oil pressure will be lower than runup and higher RPM operation. In other words I expect the student to be aware of the connection between oil temperature and pressure and RPM. So for example they would know in a hot engine that idle oil pressure in the yellow (low) range is normal but the same indication during a runup (or worse inflight) would be immediate grounds to terminate the flight.
I also review the expected engine guage indications that one would see for the likely emergencies of low oil quantity, oil pump failure, congeled oil cooler, and an inappropriatly bypassing oil cooler.
Finally I emphasize the importance of monitoring guage trends. It is not good enough to say the guage is "in the green" the student must be monitoring the value ( or the relative needle position for those horriblle Cessna/Piper guages with no numbers
). So for example iif the oil pressure in cruise started at the high end of the green arc but is now at the low end of the green arc it is time to starting thinking about what would cuase this and understanding this could be an early warning of an engine failure... even though the oil pressure is still "in the green".
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Thanks for the responses - I think I created a bigger thread than I first imagined on this subject but very good info! I passed the exam with flying colours and the oil pressure question was there so I managed to answer it correctly 