ATPL theory questions

[Wrist Watch]

I always undetstood that flight crew had to have oxygen for the entire flight time above 10 000
Which is correct if you're in an unpressurised aircraft!
If you're just starting to learn the ruthless oxy regs (for the 070 exam), I'd start by making a bold distinction between pressurised and unpressurised aircraft and the respective supply requirements for flight crew, cabin crew, and passengers (with their percentiles). Any 070 book will have summary tables.

[rudestuff]

I get that there is a difference between pressurised and unpressurised - but it doesn't mention that in this reg.

[Booglebox]

Alex, has the BGS Online question bank been updated with the new Ops Procedures questions? Thanks.

[Alex Whittingham]

I've been away for a week but before I left there were at least 60 new (A) questions added in 070 and around 40 new (H) questions. Will report back on Monday. We have had no success trying to get the CAA to either consider this as a quality issue or to publish the syllabus they use. pilot career news article (http://www.pilotcareernews.com/caa-refuses-to-introduce-quality-control-for-atpl-exams-despite-schools-pressure/) explains. The CAA say there are more new Op Procedures questions to come but this month I am told VFR comms is the exam with new questions.

[RedBullGaveMeWings]

Just out of curiosity, is it possible to know what the situation is like with other authorities around Europe, especially in Poland?
The current UK CAA situation is scaring me a bit.

[paco]

Some of them will lag behind as some of them don't use computerised systems, but the new questions are available to all authorities.

Phil

[Alex Whittingham]

All the Authorities were given ECB03 in November with 9 months to implement it. The requirement is for them to examine with questions drawn from the ECB. They don't have to use them all although most do because they don't have either the resources or the will to filter through them. Paradoxically the UK CAA are among the best of the 'Competent Authorities' generally with a proactive approach to improving the European Question Bank. In this case, though, I'm afraid they could have done better. In particular, to justify the exams by saying 'the questions are covered by the learning objectives' despite being told repeatedly (and very forcefully) that (1) the objectives themselves are flawed and (2) that the questions being generated are often poor, and secondly to take no action to set up adequate quality controls is an abrogation of the responsibility that they have as a public body examining a professional qualification. In addition, to justify the inclusion of questions as 'covered by the learning objectives' whilst simultaneously refusing to publish those very learning objectives is bizarre, and they should correct it immediately. How on earth are students meant to follow their instruction to 'study the learning objectives and not rely on question banks'? It beggars belief.

[keith williams]

The matter of what constitutes a good question (factually accurate and unambiguous) has always been a thorny one. Questions are often written by instructors who presumably feel that their questions are perfectly good. Instructors from other schools then see these questions in feedback from their students and come to a very different conclusion. Part of this problem is caused by different interpretations, but part of it is also caused by differing levels of instructor knowledge. A solution to this problem is unlikely to be achieved any time soon.

The matter of questions being based on published learning objectives should be easier to resolve. PACO, you have written some of the new OPS questions. Did you base these questions on published learning objectives?

[Dream2Jet]

Hi there, I sat the exams last week, gutted I failed VFR Comms, I passed Met and got Ops thanks to the recent hard work from people who had sat it before. Personally think its a joke, been to Uni twice and these exams are the hardest things I have done. The Met paper I got was really really hard, some stinker questions and I got a mid 80 pass, never failed a VFR Comms paper and got 60 odd in it, 11 of the questions I was struggling with, never seen them before and did not understand them and did not see how they were Comms related.

I think its a joke and the recent article by Alex W shows the hard work and dedication that he puts into his work with his students. I called the CAA got some phone operator who didnt know what an exam was, spoke with a manager who didnt know about the exams either. Its a joke and a waste of £68 but its the CAA, accountable to no one!

[paco]

Hi Keith - question writers are given a range of LOs within which to write questions. There is no choice on our part, so the answer to your question is yes. At present they are beefing up areas in which there has been no activity, so you will see many questions for LOs that have previously been given no attention. If you think it's bad enough as a school trying to teach in those areas, it's harder when you don't understand the LO in the first place!

I don't know what questions, if any, have already been written and it is often hard to come up with something original that is of practical use to a pilot. I have subjects for the next round that I would rather avoid for this reason!

The next problem are the technical reviewers - it is a lottery as to whether they know anything at all.

I must say at this point that the ladies who do the initial reviewing of a question as to its viability as a question (i.e. non-technical aspects) are pretty good at their job.

Some of the recent OPS questions actually should not have been in the exams at all - we had a recent CPL(H) candidate who got 4 questions on the ILS, which is not even in the LOs!

[Alex Whittingham]

Here is another example of a question not covered by the learning objectives from this last week's Comms exam:

Q. When would a METAR cause an immediate update to an ATIS?

(a) Upon receipt of a METAR SPECI (correct)
(b) Upon receipt of any official weather, regardless of content change or reported values
(c) Only when the ceiling and/or visibility changes by a reportable value
(d) Every 30 minutes if weather conditions are below those for VFR; otherwise hourly

The correct LO for this would be something like:

"State the circumstances when a METAR would cause an immediate update to an ATIS".

The closest actual LO is, in VFR Comms:

"List the contents of aerodrome weather reports and state units of measurement used for each item
- Wind direction and speed
- Variation of wind direction and speed
- Visibility
- Present weather
- Cloud amount and type (including the meaning of CAVOK)
- Air temperature and dewpoint
- Pressure values (QNH, QFE)
- Supplementary information (aerodrome warnings, landing runway, runway conditions, restrictions, obstructions, windshear warnings, etc)"

How could a candidate anticipate that question from the existing learning objective? This is the point we are trying to get across to the CAA. There is no way that we can prepare candidates for some of these new questions in advance of their issue. This also reinforces Paco's point about the review of technical content. We are told that these questions have been past two subject experts for validation. Really?

Out of interest, this point is not covered in the Met LOs either, the closest LO there is:

"Describe the meteorological content of broadcasts for aviation:
- VOLMET, ATIS
- HF-VOLMET"

[Dream2Jet]

Datum, definition is chosen on longitudinal axis of a/c but not necessarily between nose and tail of a/c.

Where else would it be if not between the nose and tail?

In CAP696 MRJT1 it has the datum on the nose in the pic yet it says the datum is located 540inches fwd of the front spar? How is this?

Many thanks.

[Alex Whittingham]

The datum could be anywhere. Often on fixed wing aircraft it is the front bulkhead but it could be a position in space in front of the aircraft, maybe relating to a position on the jig when the aircraft was built. Helicopters often use the rotor mast.

The advantage of a forward datum is that all moments are positive. If you chose the main spar, say, then masses forward of the spar would have a negative moment, masses aft would have a positive moment.

On the MRJT the datum is defined as 540" forward of the front spar. It's not exactly on the point of the nose, it may be co-incidentally at the front pressure bulkhead but I don't think so, the maintenance manuals seem to show that being at STN178, 26" back from the datum.

[GREGDH]

Sat my air law exam today for my ATPL ground exams i had two question which asked about the use of the transponder in an emergency and hijacking had the obvious correct for emergency of 7700 and 7500 for Unlawful interference but it wanted me to state whether it was on Mode A or C unfortunately i picked Charlie as i thought it gave more information which would be relevant for the emergency. the correct answer was mode A can anyone let me know why this would be the case?

[Jaair]

It depends on the type of interrogation received by the transponder. If it receives a Mode A interrogation, the squawk code will be transmitted. If it receives a mode C interrogation, the altitude is transmitted.

It is important to understand that squawk code and altitude are NEVER sent together by the transponder.

[wanabee777]

Don't feel bad Greg. I would've missed it too.

[paco]

Are you talking about the C of G datum or the station number datum? They are often different.

[Dream2Jet]

Hi to calculate the allowable TOM, factors that need to be taken into account include? The sum of the Max Landing Mass and Trip Fuel, why is this, i dont follow why the MLM is relevant to TOM. THanks.

[keith williams]

If the flight goes exactly as planned we will have burned only the planned trip fuel. So the landing mass will be the take-off mass minus the trip fuel. But we must not plan to land at a mass greater than the MLM, so working backwards if we take the MLM and add back the trip fuel, we will have the maximum TOM which will avoid exceeding the MLM.

[Dream2Jet]

Thanks Keith, I dont follow this question if you can help:

A mass of 500Kg is loaded at a station which is located 10m behind present CG and 16m behind the datum, the moment for that mass in the loading manifest is:

Answer is 80000Nm

[keith williams]

The key here is to note that the load manifest records moment relative to the datum, an not relative to the initial CG.

Moment added equals mass added (500 kg) X moment arm from datum (16 m)

500 kg X 16 m equals 8000 kg m.

Using the approximation 1 kg equal 10 Newton's, 8000 kg m equals 80000 Nm.

[Dream2Jet]

Thanks Keith!

As well, this question allowed traffic load is the difference between allowed take off mass and operating mass? What does this mean?

Last one, what is a simple definition of MAC.

[keith williams]

If you look at the first section of the CAP696 you will find a list of definitions.

Dry Operating Mass (DOM) is the mass of the aircraft with no usable fuel and no traffic load.
Operating Mass (OM) is DOM plus take-off fuel.
Take-off Mass (TOM) is OM plus traffic load.
So TOM is DOM plus take-off fuel plus traffic load.
There are various factors which can limit the alowable TOM, allowable take-off fuel, and allowable traffic load.
so we can say that maximlm allowable TOM equals DOM plus allowable take-off fuel plus allowable traffic load.

For CG purposes it is enough to know that,
MAC is the average chord length and it occurs at a specific point along the span of a swept wing.
The leading edge position of the MAC (leMAC) will be specified as a longitudinal position relative to the CG Datum.
The CG position expressed as a %MAC is ( (CG position - leMAC) /MAC Length ) X 100%.

[Alex Whittingham]

For interest, these are the national pass rates for the UK ATPL(A) exams in February, the low pass rate in 071 does not reflect the true fail rate in week 1 as it also includes exams later in Feb when we had some feedback in place and pass rates were coming back up.

010 Air Law 93%
021 AGK 88%
022 Instrumentation 84%
031 Mass & Balance 86%
032 Performance 77%
033 Flight Planning 91%
040 Human Performance 88%
050 Meteorology 70%
061 General Navigation 71%
062 Radio Navigation 87%
071 Op Procedures 56%
081 Principles of Flight 72%
091 VFR Comms 100%
092 IFR Comms 95%

[theaviator2005]

Anyone know's if its the same all over Europe? I mean do they just print out the test's from an EASA main system or is it up to each country to change the questions whenever they feel like it?

There must be a bunch of old retired pilots at EASA who sit and come up with crazy s..t when sitting telling stories about their days as Spacecowboys.

The system is utter crap, I have tested JAA guys vs FAA guys about 8 years after the JAA guys finished their ATPL. They all took the same practice papers and they all got about the same scores. All pilots currently flying for airlines or corporate companies. NOT ONE passed any of the practice papers I gave them.

The amount of knowledge and information one must Study/learn and keep inside the heard is worse then even a doctor has to learn, and impossible to retain just even a few years.

Would be great-full if anyone got any knowledge about the question in the top, if its the same all around EUROPE or just the UK that are swapping out questions left and right?

[paco]

There is only one commander on a flight. ORO.FC.105.

[Dupre]

Hi All,

I have heard from a couple of people recently that wrote Air Law, who said they barely recognised any questions on the paper from the database they subscribed to. How long do the database providers take to come up with updates to cover major changes like this?

I am sitting it next month... and starting to worry a little!

(not that I am only studying the qb, but Law in particular is a very wide subect and the qb helps narrow down what is important and what is not...)

[Alex Whittingham]

The answer is that it is reactive, neither the database providers nor the schools can anticipate the direction the exams will take because (1) the syllabus we have been given is so badly written almost anything can be asked (2) the questions being created are in a large part not properly validated.

Once the questions appear we can modify our feedback. An example is Op Procedures where improved feedback was allowing passes on the new material within two weeks. In some subjects feedback is very difficult to get right because the questions themselves are wordy and complex (Air Law), in other subjects it is relatively easy to get right.

The situation is not helped by the poor english of the examiners, by inconsistent use of reference documents, by questions with answers that are just plain wrong and by the exam authorities bending over backwards to avoid crediting exams, which means defective questions are not removed.

All in all it is a shambles, and the JAA and EASA have been trying to get this right for 15 years. It is unfair on the candidates that have to sit these new exams. EASA and the CAA say that the new questions are an effort to stop people relying on question banks. The paradox is that the effect of their poor quality of work is exactly the opposite of their intentions.

Very few people complain because there is a feeling that the regulator will 'black spot' you if you do. There is no quality system that applies to the exams, no external regulation either. Even the schools are reluctant to complain and be seen as 'trouble causers'. To paraphrase Juvenal, who will regulate the regulator?

[Binners93]

Evening all,

I have begun my studies for the ATPLs with BGS and am going through their maths & physics premodule before starting with the official subjects. So far, I've recapped factors (HCF, LCM), long division and multiplication and shape properties without issue, but one question on formula rearranging is really getting me down because I just can't understand it!
The question is transpose y=7-2x to make x the subject - should be straightforward enough right?
As I understand, the first figure to the right of the = sign will be a positive unless otherwise indicated, so my first step would be to get rid of this (7-7 = 0). Doing the same to the other side, the first issue appears, is it y-7 or 7-y and why?
Secondly, Now being left with -2x is also confusing me. To balance this back to x, are we dividing by -2, resulting in (y-7 or 7-y)/-2 = x? The answer doesn't think so and neither do I, but not sure why :bored:
It's only this one question that seems to be catching me out so far and its driving me insane! Rearranging the C=(5(F-32))/9 formula to make F the subject was straightforward compared to this easy question!!? :ugh:
Hoping not to fall at this first hurdle and that someone can assist in making me feel not quite so stupid! :confused:

[average-punter]

It's always worth making the subject of the equation positive in the first instance, to avoid any silly errors by having to multiple by -1 at the end.

As I understand, the first figure to the right of the = sign will be a positive unless otherwise indicated,
Correct.

You ultimately want to get the subject on it's on in as few a "moves" (for lack of a better word!) as possible

So with this in mind....

y = 7 - 2x

I'm going to add 2x to each side of the equation (as I want to get the subject positive), alternativly you could multiply everything by -1 but I favour the first method.

y + 2x = 7

Then subract y from each side

2x = 7 - y (there is 0 y on this side of the equation hence why is becomes "-y" -y is the same as -1y)

then finally divide each side by 2 (as there are 2 lots of x on the left side. If we know that 7-y gives us twice the value of x, then half on 7-y must give us x!)

x = (7-y)/2

[ManUtd1999]

y is positive so subtracting 7 from each side gives (y-7)=-2x

As you said, dividing by -2 on each side gives (y-7)/-2 = x

This answer is correct but I expect the textbook is the re-arranging the left-side which is confusing you

(y-7)/-2 = -(y-7)/2 = (7-y)/2

[Ascoteer]

I just sat Mod 2 and, although I passed the exams, AGK and Air Law had 15-20 new questions. Some of these aren't in the ATPDigital Syllabus and it took serious effort to try and find an answer (for example, when can an ICAO country ask its citizens for an exit visa). I just don't understand how you can realistically study for the exams that aren't logical/mathematical. Is there a public list of the learning objectives available anywhere?

I knew the question bank and syllabus inside out and still had to guess a number of answers!

[paco]

You should be able to get them from EASA, but I believe they may also be on BGS's website.

[speed_alive_rotate]

Just struggling a little in fully grasping the concept of swept back wings regarding some of their traits:

I understand all the positives of getting a swept wing to stall at the root first and to prevent a wing TIP STALL , however another general question keeps coming up and I am getting a little confused.It is as follows:
Why so important to prevent a stall at the root of a swept back wing??

Also does anybody have any good links about swept back wings , their advantages, disadvantages etc , movement of C of G and C of P .

Appreciate all inputs and thoughts.

[flyfly4]

Can anyone share some feedback from the OPS exam? It seems it's still with so many questions outside the learning objectives

[paco]

I don't think that's the case. The current vetting process is quite rigid and I can assure you the new ones wouldn't be there if they weren't within the LOs - the technical reviewer in this case is well up to speed. Are you sure you don't mean "not in the commercial databases"? :)

[flyfly4]

well, feedback from other students that just did the exam told me that there were so many new questions from areas not taught from the teachers nor in any QB: AE/BGS/ATPLOnline

thanks paco ;)

[Ascoteer]

I don't think that's the case. The current vetting process is quite rigid and I can assure you the new ones wouldn't be there if they weren't within the LOs - the technical reviewer in this case is well up to speed. Are you sure you don't mean "not in the commercial databases"? :)

All very well, but you'd expect the questions to at least be a) correct and b) representative of the real world. There are plenty of questions where it's nigh-on impossible to find the source document and some which are just plain wrong (and I speak from many years of operating transport aircraft in Europe). There was even a question referenced to the Oxford Aviation School Syllabus, surely an indication of, at worst, endemic corruption, or, at best, an unhealthy level of incestuousness.

It seems to me that question writers are being paid to participate in a game of 'who can unearth the most obscure fact' (rate of air dispensation from a mask, anyone?) instead of focussing on elements which are relevant to operations and, crucially, would be important/essential to know when flying a real aircraft.

[SkillsToBurn]

As of last week 11/05/16 I sat my Principles of flight and OPS exam. Before attempting to even book the exam I wanted to, under the current feedback students have been giving build myself up to getting at least 90% on practice exams within the question banks, yes BANKS, I used bgsonline and Aviation exam to try and give myself the best possible chance of passing the exam. Having done so and getting averages of 90-92% I couldn't feel any more confident going into an exam. Chosen venue Gatwick! Result, 61% POF, 71% OPS. I was astounded to say the least. I was aware of feedback given for the OPS exam but POF was a joke. The exam was majority based on subsonic Aerodynamics and control, there was no prop theory, 1 question on High speed flight, nothing on gust load factor, Ground effect, oblique shock waves, induced drag and flow separation, neither to my surprise did I have to use my calculator as, low and behold there were no questions asking me to calculate aspects such as Lift or radius of turn. All topics listed came up within practice exams. I am not sure whether this is appeal-able under the circumstances that not all learning objective questions were covered??? To give myself piece of mind after the exam I decided to also purchase ATPL on-line this being the 3rd question bank, multiple times I was averaging 85-90% over all 3 banks. I can safely say I know the subject inside and out, however, under this new system you will have to pray that when you click that start button the computer isn't going to generate all these newly written CAA/EASA questions because if it does you will need luck a guiding hand and every ounce of knowledge learned to give yourself the best chance of an educated guess. This is series 2 for me as my last set timed out, iv been through JAR and EASA and can tell you from experience that if individuals are starting to fail subjects like ops and coms you know somewhere down the line the system is flawed.

On another note, are these new questions just being asked in the UK or Europe as a whole?? After all "EASA" right! Hard to tell without concise feedback from all the schools communicating with each other. Im sure though if it were the case alot of people would be on the next flight to Spain! :\

[ersa]

I can safely say I know the subject inside and out

You mean you know the question banks inside and out, not the same has knowing the subject.

[paco]

The new questions are being farmed out all over Europe, at different stages. Most countries should have implemented them by now.

My comments above refer to the new sets of questions that have been written over the past couple of years, so there will be a sprinkling of the old garbage. I know that many of the ops questions have been based on real world experience, and the technical reviewer involved is a very senior instructor with plenty of experience and knows what he is doing. I also know that some of the tech reviewers on the POF side (for helicopters, at least) are questionable, to say the least (one of them asked what "being downwind" meant), but these are appointed by national authorities, not EASA. In the ops case, the UK CAA.

To be fair to the question writers, some of the LOs leave very little to work on, but the new NPA is being announced on the 15th, so there is hope in that area :). Now all we have to do is get to work on the questions.

As for source documents, it might help with ops if you actually read Commission Regulation (EU) No 965/2012 rather than rely on the banks.

[Martin_123]

first feedback from the very recent Human Performances takers suggest similar fate, students left disappointed and questioning learning objectives etc.. anyone got any feedback on this one?

[Ronaldsway Radar]

I am studying Ops at the moment. This feedback makes me very nervous!

I agree that you can't 'trust' your results from the question banks as a reliable indicator of how the actual exam might go, but the thing is the practice exams provided directly by my course provider are very similar to those on the online question banks. So if neither they nor the question banks can reliably indicate the possible outcome of the real exam, how is one supposed to know if they are ready or not?

It seems excessively difficult to judge at the moment, which I can only feel is unfair on people paying through the nose to turn up essentially unprepared.

However, Paco I had the same thought when I started Ops so I am slowly working my way through 965. I hope those additional hours are worthwhile.

[paco]

Do please let us know - it works around here.

[SkillsToBurn]

I completely agree with you Ronaldsway Radar (http://www.pprune.org/members/102286-ronaldsway-radar). However on a positive note Bristol have been very quick in updating their question bank with feedback on the new EASA style questions for OPS. Lets hope they can keep this up with all the other exams. Time will only tell!

I just sat ops and it wasnt too bad to be honest with you, the new questions I came across were:-

Flight deck crew communicate in....... A COMMON LANGUAGE
Does an infant require a seat..............NO
Routine questions on Fire Extinguisher i.e 300-400= 5 Extinguishers
Crew Duty time
OPS Manual A,B,C,D
If you experience a Engine fire in flight your first action is to.......

A) Don on oxygen mask and Goggles
B) Pull Fire Handles
C) Shut down the engine
D) Select Max Continuous thrust <<<<<<<

[Alex Whittingham]

Seriously? No mention of QRH actions? If your memory is correct that is appalling.

From the B737 QRH as an example these are the immediate actions....

1 A/T ARM switch
(affected side) . . . . . . Confirm. . . . . . . . . . OFF
2 Thrust lever
(affected side) . . . . . . Confirm. . . . . . . . . . Idle
3 FUEL CONTROL switch
(affected side) . . . . . . Confirm. . . . . . . CUTOFF
4 Engine fire switch
(affected side) . . . . . . Confirm. . . . . . . . . . Pull
5 If the FIRE ENG message stays shown:
Engine fire switch . . . . . . . . Rotate to the stop
and hold for 1 second ...etc.

If true, so sadly typical of the rubbish being put out as exam questions. The answer is "follow the QRH for the type"

[SkillsToBurn]

Afternoon Alex,

Indeed no mention at all of QRH. Straight after the exam I called and spoke to Tom. We had a rather lengthy discussion on this question, we came to the conclusion that, if indeed the Engine was on fire it would not have necessarily failed therefore shutting down the engine would be wrong and came to the conclusion that selecting max continuous thrust on the normal operating engine would be correct!!

Learning objectives, what learning objectives!!

[Alex Whittingham]

I think that depends on the phase of flight. For instance if you had a fire after V1 and below 400ft the only immediate action on most aircraft would be to cancel the aural warning. I'm pretty sure Tom is giving you 'set MCT' as the best of a bad bunch. It is certainly not (a).....(b) and (c) have the same effect.... (d) would be correct for an engine failure in the cruise on the basis of 'first fly the aeroplane', but only while simultaneously calling for the QRH.

[paco]

Are we sure the recollection is correct....? ;)

[flyfly4]

which question is wrong you think paco?

[paco]

The Fire one. Don't ask why.....

[Alex Whittingham]

I'll bite. Why?

[paco]

I don't know :) I just have it on good authority that student recollection is not correct - it will no doubt be in the CTKI circular anyway.

[wipeyourfeet]

Heard some rumours milling about that grid nav is no longer appearing in Ops tests. It's still in the L.Os though. Anyone able to confirm/dispel the rumour?

[flyfly4]

thanks Paco.

[RichardH]

A student reported that they got a Grid Nav in a recent OPs exam. Another also reported 7 Polar Stereo questions in GN.

[I'll Be Realistic]

Is it possible, Paco, that you wrote a question along these lines, submitted it, then it went through the full proof (sarcasm) checking process and was changed in some way, which then brought doubt in to the answer?

There gets a point where for instance the fire question needs to be released as it was given to the student, confirmed by the student that it was in deed given that way, and if it is a bad question, the writer, the checkers and the authority should be held accountable.

I'm sure a great many authority bods think they are making the skies safer with these moves, but I bet if we ran any of them who are still flying through the same test they would fall flat on their face. Does that mean they should surrender their licence because they are not safe?

It is farcical to learn these regulations when they could change the day after a student takes an exams.

Better that the student be given a set of questions and the regulation and told to go find the answer. And require him to get 100%.

[paco]

It's not mine :)

Anything is possible, of course, as once it has been checked against the methodology (and the girls who do it are sharp cookies) and technically reviewed, I shouldn't see it again. All I can say is that I get questions sent back for a typo which could easily be done by EASA, and each question has a full audit trail of comments, so it is unlikely.

I hear you about regulations, but you have to draw a line somewhere - helicopter pilots are still on JAR OPS, at least until very recently. The trick there is not to be too specific.

Re your last comment - some authorities don't have the facilities for open book - in flight planning, for example, the Jep stuff will be in the question now, rather than using the book. I don't see the problem, but there apparently is one. In this respect, EASA don't seem to be able to enforce rules - instead they leave their interpretation to the local authority, which means we are no better off than under JAA.

The German system allows questions that require a typed in answer that must be correct - a good move in my opinion.

[gerardflyagain]

Hi

I'm studying for exams and understand the Coriolis effect. However, I don't understand why it would apply when travelling just east to west or vice versa (bit I'm pointing to in the pic deflecting right). Surely the ground underneath rotates at the same speed relative to the wind the whole time when it's just east to west (or vice versa). I understand that if travelling north as in '2' below, the wind would be moving faster than the ground underneath it.

Can anyone explain please?

[Alex Whittingham]

I think you are correct, it doesn't, and you first diagram is incorrect. Where is it from?

[Gargleblaster]

Imagine we stop the earth's rotation, just to illustrate how objects moving towards east or west behave.

Imagine you could shoot a magic bullet, one that keeps moving forever at the same speed and height above earth's surface.

If you shoot the bullet towards the east, it will NOT circle the earth at the same latitude. It will start going towards equator.

The reason is that all such movement will follow a great circle. Hence, there is always a north / south movement, unless you are on the equator.

Imagine standing on the north pole. You walk a hundred yards in any direction (south). You shoot your magic bullet to the east. You wouldn't expect it to circle the pole, and hit you in the back a second later, no ? It will fly all the way towards the south pole, pass it at a hundred yards, and then back.

[Alex Whittingham]

Interesting, and it makes me question what I thought I knew. But if your analogy is correct, Gargleblaster, a bullet fired in a westerly direction in the northern hemishphere would deflect to the south as well, ie to the left. But this is the opposite of how the coriolis force works.

While I think about it I have grabbed a bit of Wiki that seems to support the idea that coriolis acceleration depends on the direction of movement:

In non-vector terms: at a given rate of rotation of the observer, the magnitude of the Coriolis acceleration of the object is proportional to the velocity of the object and also to the sine of the angle between the direction of movement of the object and the axis of rotation.

https://en.wikipedia.org/wiki/Coriolis_force (https://en.wikipedia.org/wiki/Coriolis_force) (the 'formula' section)

[gerardflyagain]

Thanks for the responses.

Alex, it's just from google images but I've seen plenty of other diagrams saying the same thing.

Gargle, by all movement 'follows' the great circle, do you mean all movement is drawn to the great circle (equator)? If so, why? And, as Alex said, wouldn't that mean in your analogy shooting west, Coriolis would deflect it to the left? If so, that is contrary to the notion that Coriolis always deflects right in northern hemisphere.

For your analogy, I don't know what I'd expect, but circling the north pole and hitting me doesn't feel any more 'wrong' than flying to the south pole, passing at a hundred yards and coming back.

[harrysingh]

Any feedback from recent exams regarding Performance (A) and flight planning?

[paco]

Re the Coriolis thing - I'm not sure if this will make it any clearer, but after much scratching of the head (it was a 2-Columbo problem).......

There is no Coriolis at the Equator within about 20 degrees either side, but elsewhere, when going East, you are moving with the Earth, so your velocity is greater (similar to having a tailwind). Of course, going the other way, you will be going against the Earth's rotation, and will be slower.

You are accelerating, in that the nose is going downwards to maintain your altitude, so there is an element of centrifugal force involved, changing its value with the changes in acceleration mentioned above - enough to cause a deflection towards the Equator when moving faster than the Earth, i.e. West to East, or towards the Pole when travelling slower than the earth, or East To West. Either way, the deflection is to the right.

The centrifugal force is balance by gravity when you are at rest, but once you start moving, it changes.

Back to Columbo...

[SkillsToBurn]

In order to know in which mode the auto-throttles are engaged, the crew will check the:


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-A.pngPFD (Primary Flight Display)<<<<<<<<<<<<<<


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-B.pngTCC (Thrust Control Computer).


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-C.pngThrottles position.


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-D.pngND (Navigation Display).

In my exam the question was worded exactly the same but PFD (Primary flight Display) had been Replaced with FMA (Flight Mode Annunciator) I.e in the exam it was represented like this :-

In order to know in which mode the auto-throttles are engaged, the crew will check the:


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-A.pngFMA (Flight Mode Annunciator)<<<<<<<<<<<<<<<<<<<<<<<


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-B.pngTCC (Thrust Control Computer).


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-C.pngThrottles position.


https://dub129.mail.live.com/Handlers/ImageProxy.mvc?bicild=&canary=YycOzzet1ckOV%2bkoi4gPzPACvcB%2b0R9y%2fy0wg%2bLBHfo%3 d0&url=http%3a%2f%2fqbank.bgsonline.eu%2fStyling%2fimages%2fopt ion-D.pngND (Navigation Display).

[Alex Whittingham]

It is indeed a 'two Columbo' problem. Having given it much thought and googling I reverse my earlier position and agree that the diagram is correct, when travelling due east or west there is a coriolis force to the right. Paco's explanation above refers to an element of upward acceleration travelling east from which the coriolis force derives, which is I think correct. The mathematical approach on Wiki (https://en.wikipedia.org/wiki/Coriolis_force#Meteorology) under 'rotating sphere' appears conclusive.

[Dream2Jet]

Hi, I need to review these subject areas for my a repeat AL exam, not quite sure which areas these relate to, anyone know? Thanks.

010.01.04.01
010.02.01.00
010.05.03.00
010.05.04.00
010.05.06.00
010.06.04.02
010.06.06.02
010.06.08.01
010.07.02.02
010.07.02.13
010.08.04.03
010.09.08.02
010.10.02.03
010.12.06.00

[ersa]

010.01.04.01
010.02.01.00
010.05.03.00
010.05.04.00
010.05.06.00
010.06.04.02
010.06.06.02
010.06.08.01
010.07.02.02
010.07.02.13
010.08.04.03
010.09.08.02
010.10.02.03
010.12.06.00

try these



http://www.lba.de/SharedDocs/Downloads/DE/L/L2/LOs-FDB-010.pdf.pdf?__blob=publicationFile&v=2

[gerardflyagain]

Thanks Alex and Paco. Unfortunately, your explanations still don't make sense but I will trust you. I suspect if I was walked through the maths in the wiki link it would make sense, but I don't have the ability to do it myself.

[keith williams]

geraldflyagain,

I suspect that your difficulty stems from the fact that ATPL studies concentrate only on the effects of northerly and southerly movement. But movement in any direction over the surface of the Earth will cause coriolis effect.

If you do a google search of Eotvos Effect you will find a link to a wikipedia article. The maths may prove to be a bit off-putting, but the diagrams and explanations (particularly in the section of motion along the 60 degree latitude) will probably be more helpful.

[joshuahsong]

Here's question.
We are cruising at pressure altitude of 9000ft.
The OAT is -5 degrees celsius.
Calibrated airspeed is 170 knots.
What's the exact true airspeed under these circumstances?
I do know the answer, I need to know the formula.
Please help.

[EC DKN]

Hi,

You need to use the CRP-5:

1. Set Press Alt 9000 with -5 OAT.
2. Find 17 (170 kts CAS) in the inner scale
3. Read the outter scale which is 194 kts (TAS)

TAS= 194 KTS.

Alex or Paco can correct that as I am just student :)

[Cat3C.ATPL]

Absolutely correct EC DKN.

Of course, there will be a mathematical formula which can convert a CAS to a TAS but this type of question can be calculated simply and quickly using either a manual flight computer such as the CRP-5 or an electronic flight computer, the latter of which are permitted by some aviation authorities, e.g. FAA, but not by EASA.

I will expand your answer slightly:

1. Refer to the CRP-5's AIRSPEED window.
2. Set the Pressure Altitude of 9,000' on the scale inside the window against the Outside Air Temperature of -5 degrees on the scale outside the window.
3. Look up 17 (170 kts CAS) on the CRP-5 inner scale
4. Read the TAS of 194 kts on the CRP-5 outer scale.

(*I don't have a CRP-5 to hand - unforgivable!! :eek: - but I have 100% confidence in EC DKN's answer ;) )

I hope this helps. :ok:

[latecoere240]

You can calculate it.

Density correction : You add 1% / 600ft. In this case 9000/600=15%
170*1.15=195 kt

Temperature : In standard atmosphere at 9000 ft it should be -3 (15-9*2).. The OAT is -5.. It's 2 degree colder..
you correct 1% per 5 degree difference.

170*1%*2/5=0.7

195-0.7=Approximately 194KT

[oggers]

Here's question....I do know the answer, I need to know the formula.

Hello Josh,

The formula is: TAS = CAS/√Relative Density

1.225 kg per cubic metre being standard SL density, the relative density is: air density at altitude/1.225

Note the above does not include correction for compressibility which is generally considered insignificant at the lowish speed and altitude in your example. To correct for compressibility you would substitue Equivalent Airspeed for CAS in the formula. I lifted the formula straight from my RAF gorundschool notes. There is a similar formula in "Aerodynamics for Naval Aviators" which is freely available online if you search for it.

[latecoere240]

eggs, there is no need in this example to talk about compressibility. Speed is less than 250 kt.
Regarding density of the air the most important to know>>> what does affect it :
-Pressure (Altitude)
-Temperature
-Humidity

[EC DKN]

Wrong, compressibility error is applied above 300kt TAS!! Look the CRP-5, it doesn´t make sense 250/100-3 DIV!

[Alex Whittingham]

Er compressibility is corrected for 'initial' TAS in excess of 300KT on the CRP-5, it is true, but FAA docs say compressibility can be ignored below 200KT and 10,000ft. EASA questions seem to say 200KT and ignore the 10,000ft bit. It's a matter of judgement, at what point can a very small compressibility be ignored? How do you express what is essentially a mach number in terms of TAS/CAS/altitude? Is the FAA 200KT a CAS or a TAS? Depends on the reference material. The reference material isn't quoted of course, that would be too partisan.

[oggers]

Latecoere:

eggs, there is no need in this example to talk about compressibility. Speed is less than 250 kt.

Actually the guy asked for an "exact" answer and a formula, so I gave the formula both with and without compressibility. And I also wrote "compressibility is generally considered insignificant at the lowish speed and altitude in your example".

Regarding density of the air the most important to know>>> what does affect it :
-Pressure (Altitude)
-Temperature
-Humidity

I was answering the question the OP asked, as opposed to the question you think is more important :ok:

The formula is: TAS = CAS/√Relative Density.....the rule of thumb you gave is a useful approximation. We all use them. But it is an approximation and the OP asked for an "exact" TAS.

[latecoere240]

Well, I already know the formula.
Everybody can find easily this formula and it's not only part of your RAF notes and aerodynamics for Naval aviators.Now demonstrate your calculation with this formula and your answer..

Indeed It's an approximation but quiet representative.it's more pratical and it seems we found the same result of the CRP-5, AVIAT 617 or any kind of flight computer..

[oggers]

The OP specifically asked "I do know the answer, I need to know the formula". So, I gave him the formula and cited my source. You didn't :ok:

Why do you have a problem with that? Genuine question.....

[latecoere240]

Well i can give another source with a different way of formula:

TAS : CAS +/- density error +/- compressibility error or EAS +/- density error

The source : OAA

I don't have any problem, but i guess you don't know to use it !
He does know the answer but doesn't know to calculate it.. You don't help that much...

[oggers]

Latecoere

The OP asked for the formula for TAS. Neither of us know whether he wanted the proper formula I gave or the - admittedly useful - approximation you gave. I simply answered the question, if you want to be the arbiter of the best formula fill your boots. Nobody else cares. Both are up there, the OP can take which one he needs. The end.

[s4ex]

I've came across interesting question, which I cannot understand, so maybe somebody could give an idea why.

At 10:15 the reading from VOR/DME station is 211deg/90NM, at 10:20 the reading from the same VOR/DME station is 211deg/120NM
Magnetic Heading = 200deg
Variation = 31W
Drift = 12L
What is the True Track ?

a 163
b 157
c 180 // Correct answer
d 181

So at first, I saw the 211 Radial and calculated 211 - 31 = 180, which gave me the correct answer.

But then I started thinking more, and though, that given MH, Var and Drift and ignoring VOR radial should give the same result, so I decided to check. If I wasn't given the Radial information, then True Track calculation would be :
(MH) 200 - (VAR West) 31 - (Left Drift) 12 = 157(T)

So obviously it was a wrong approach, however in the questions, where the VOR radials are not mentioned, only MH, Var and Drift given, that is the way how True Track is calculated.

In reality I'd expect both calculations give the same result (ignoring the Deviation). So why the VOR reading in this case is given the priority, or am I missing something ?

Thanks.

[Alex Whittingham]

Looks like the drift is given incorrectly in the question. Had it been 11° right (or 12°) you would have calculated a track of 180° (or 181°). My guess is that whoever set the question got left and right muddled up. Where was this from?

[s4ex]

Thanks for explanation. That might be true, or just a typo. Got the Q together with the list of questions from somebody I know while preparing for my PPL exams. Not a public source.

[gerardflyagain]

Thanks Keith.

I have another question. Are there mini quizs available any where?

I am about to transition from Pooley's books to Phil Croucher's EASA ebook. I think the book is excellent (although I'd like a bit more colour :) ) but one thing I miss is the mini quizs per section of a given topic. For example, in Pooley's air law, when I finished the chapter on Visual Flight Rules, I could then do a quiz on it. If I had to finish the whole of air law before I could do a quiz (which is how ppl tutor et al have it) then I'd have forgotten half of it by then!

[paco]

A good suggestion - I will schedule that in for the next update.

[selfin]

TAS : CAS +/- density error +/- compressibility error or EAS +/- density error

TAS cannot be obtained from CAS or EAS by using independent linear terms.

... the proper formula I gave ...

The formula is: TAS = CAS/√Relative Density ...

This formula requires a loss of distinction between EAS and CAS which may be an acceptable assumption at low speed and low altitude. As either speed or altitude increase above some threshold - see Wittingham's post here on 2016/06/03 - the assumption leads to an increasingly erroneous TAS value and it is the difference from the correct value which is referred to as, rightly or wrongly, a "compressibility error." Latecoere240 therefore probably wanted to write your formula but with the addition of a corrective term. That is, I suspect the intention was TAS = CAS/sqrt(sigma) + compressibility_error; sigma being the ratio of ambient air density to the ISA MSL value as you've given.

It is incorrect to state TAS = EAS/sqrt(sigma) + compressibility_error; EAS might as well be defined by the expression TAS * sqrt(sigma), i.e. no corrective term is needed when mapping EAS to TAS or vice versa.

It's crucial to note that this compressibility_error is a function of CAS and altitude and that the effort needed to compute TAS this way is not less than working it out directly in the first instance. The function needed to do this mapping which is mechanically effected in modern airspeed indicators, and has been since the Tiger Moth, may be found in William Aiken Jr's NACA report 837 (1946), Standard nomenclature for airspeeds with tables and charts for use in calculation of airspeed, available from the Aerade Reports Archive hosted by Cranfield University here: NACA UK Mirror report description page (http://naca.central.cranfield.ac.uk/report.php?NID=2451). Eqn 3 can be rearranged to set TAS (V) or CAS (V_c) as the subject as required.

[selfin]

... movement in any direction over the surface of the Earth will cause coriolis effect.

There are some excellent articles by the Swedish meteorologist Anders Persson on the effect. See here (http://www.aqqa.org/pp/persson.html) for a short list.

[gerardflyagain]

A good suggestion - I will schedule that in for the next update.
Thanks Paco, sounds good!

[engineno9]

Can anyone tell me how many total marks there are available for the UK ATPL Mass and Balance exam? I'm aware there are 25 questions but I assume there will be some worth more marks, just can't seem to find the totals listed anywhere.

[D driver]

Q. Why does doppler VOR have less site error compared to CVOR?

[paco]

Because the mountains (or similar fixed hard objects) don't affect the propagation. Instead of going round in a circle, the signal moves back and forth. The receiver can't tell the difference, though.

Phil

[D driver]

thanks for the input. But can you please elaborate what you just said?

[paco]

OK:

Using Doppler allows the frequency of a signal to decrease when the distance between the beacon and aircraft increases, and vice versa. The Doppler shift makes the transmitter look as if it is advancing and retreating 30 times a second. That is, the aircraft sees a varying frequency rather than varying power.

As mountains don't move, they don't affect the reception of the signals and the VOR doesn't suffer from propagation errors. Do you need an explanation of Doppler?

phil

[D driver]

are you implying that just because its vari phase signal is FM and that of CVOR is AM, the site error is less. And if yes is that the only reason?

[paco]

No. As mentioned above the Dopper principle removes the site errors because anything that does not move has no effect on the signal propagation. From a "normal" VOR the aircraft sees a change of power even though FM is involved. With a doppler VOR it sees a change in frequency instead.

phil

[D driver]

I read somewhere that site error in doppler VOR is less because of its bigger aperture compared to CVOR. By aperture they meant the diameter of the circle in which the antennas of the doppler are arranged. Does that make any sense to you? I dont really know what tht means.

[paco]

You mean wide-aperture? This averages out the local distortions which would normally be much more noticeable with the more narrowly focussed CVOR antenna (at about half a wavelength as opposed to about 5), so a theoretical tenfold reduction in site errors is possible (something to do with space diversity).

The Doppler shift comes from the relative motion of the antenna and the receiver. It is used because the wide aperture system needs Doppler to work properly, in that it creates the direction-dependent FM signal. The frequency change observed as the antenna rotates towards or way from an observer on the same circle is in proportion to the azimuth.

Phil

[Alex Whittingham]

all you could possibly need on youtube (https://www.youtube.com/watch?v=tZ2gG1v9Xg8)

[D driver]

thanks for the input alex, so thats how bigger aperture leads to less site error. Nicely explained. But I believe there's also another phenomenon here acting to reduce the site error called "Capture effect". This refers to the capability of aircraft receiver to demodulate only the strongest of the variable phase VHF signals from doppler VOR, ignoring the reflected but weaker variable phase signals. As opposed to the CVOR wherein the average of the direct and the reflected weaker signal is taken into account to derive a wrongful "average" bearing. Would like your comments on this.

[paco]

The capture effect is an FM phenomenon and partly the reason for the system being designed that way. AM allows multiple signals to be broadcast on the same channel.

Phil

[D driver]

so If am not mistaken, there's two effects now "capture effect" and "Bigger aperture" that is leading to lesser site error with DVOR compared to CVOR. Is that correct?

[paco]

Sort of - as I see it, the site errors are minimised with the wide aperture, the Doppler effect makes that work and the capture effect just makes for a stronger signal. Simples!

Phil

[RedBullGaveMeWings]

The aircraft maintains the magnetic heading of 060 degrees. The declination is 8°W, the drift angle is +4°. What is the true track heading of the aircraft?

a. 056 degrees
b. 048 degrees
c. 064 degrees
d. 072 degrees

It's not ATPL level, but I am not sure 072 degrees is actually the correct answer... Shouldn't it be 048 degrees?

[Alex Whittingham]

Declination? Do they mean variation? And why is drift shown as +4, not 4 left or right? How confusing can you get?

If variation is 8W and drift is 4 port, yes, true heading is 052, true track is 048. Who wrote this question?

[RedBullGaveMeWings]

Polish CAA for PPL... It's a mess. Luckily ATPL questions are from a centralized QB.

[flyfly4]

Hi Alex, both in BGS (i've been told) and atplonline(confirmed) they have this question wrong:

Which of these statements about a reaction turbine are correct or incorrect?
It's considered that it's the same question as this one:
Which of these statements about an impulse turbine are correct or incorrect?

But they are different things. Can you confirm me that it's like this in BGS too? In class we have been taught that are different things and pressure in stator and rotor difers depending if its reaction turbine or impulse turbine.

Cheers.

[Alex Whittingham]

Oh this question! I will ask my CGI so I don't embarrass myself by giving you inexact information.

[Alex Whittingham]

From my CGI, John Crosland:

This has been a hot topic for some time, mainly because reference books are cagey in their writing and many of the early exam questions had incorrect answers. We have edited BGS Online to reflect the current situation, don't know about ATP Online.

This is quoted from Rolls Royce – the Jet Engine.

“TURBINE TYPES
There are three types of turbine: impulse, reaction, and a combination of the two known as impulse-reaction.

In the impulse reaction type turbine, the pressure drop across each stage occurs in the fixed NVG, which, because of its convergent shape, increase the gas velocity while reducing pressure. The gas is directed onto the turbine blades, which experience an impulse force caused by the impact of the gasflow on the blades.

In the reaction type, the fixed NVGs are designed to alter the flow direction only, without changing pressure. The converging blade passages experience a reaction force resulting from the expansion and acceleration of the gas.

Normally, modern gas turbines rely on the combination of both design styles, and modern aerodynamic design methods enable the characteristics of components to be tailored to maximise work output and stage efficiency.”

John has given me the lists below which he thinks are correct. Caution, the few remaining exam questions may still have arguably incorrect answers.

Impulse turbine
Nozzle guide vanes
Pressure down
Temperature down
Velocity up

Turbine blades
Pressure same
Temperature same
Velocity down

Reaction turbine
Nozzle guide vanes
Pressure same
Temperature same
Velocity same
Direction change

Turbine blades
Pressure down
Temperature down
Velocity up

[flyfly4]

Yes that's exactly how it is! So in the CAA exams they have it like this too? Thanks :)

[flyfly4]

Hi Alex, I came up with some ambiguity in a question in Met and Comms. It's when you have to file a special air report when you encounter a few elements in flight. In Met questions you are suposed to file it when you encounter SEVERE turbulence, mountain waves...
but in comms it's when you encounter MODERATE OR SEVERE for the same elements.

Do you know if CAA has changed this recently in their system as valid question? Thanks a lot!!

[Alex Whittingham]

The contents of a routine AIREP include turbulence of any category. A special AIREP is required when encountering severe turbulence (and a list of other phenomenon which affect the safety of aircraft). I can find a question in our databases in met which says 'all pilots encountering turbulence are requested to report it' and then leads on to test a definition of moderate turbulence, but I can't find either a question in met testing the requirement for 'severe' as against 'moderate' in a special AIREP or the equivalent question you quote in Comms. May I ask where the questions came from?

[Okavango]

Hi all. Is anyone able to update on the current situation regarding the concentration on new LO's and associated additional, sometimes obscure questions?


From recent experience I'd noted HPL had been tickled a bit (no bad thing as it used to be a bit of a joke), Instruments had a bit of new stuff, Gen Nav seemed easier and Met again a slight tickle but the weather's the weather. Speaking to others at the exam venue and looking on here, Op Proc and Air law sound like they've been hit badly along with Comms? Are any other subjects to be treated with caution? Thanks in advance.

[flyfly4]

I will check tomorrow probably Alex, regarding the Moderate/severe.

What about this question?

At constant RPM with a normally aspirated engine and a fixed pitch propeller, as altitude increases, if the mixture is not leaned:
The density of air entering the carburettor decreases and the fuel flow increases. INCORRECT.
Both the density of air entering the carburettor and the fuel flow decrease. CORRECT

Why are they considering that fuel flow will decrease?

[flyfly4]

BTW Alex, question 210754 is wrong in BGS, regarding the NGV and rotor in a reaction turbine. cheers.

[Alex Whittingham]

I will double check for you, but I think this one of the questions where the answer marked correct ..... isn't.

[flyfly4]

For the CAA i believe that NGV in a Reaction turbine are at constant pressure. I also found this one wrong: 210757. Its the same kind of question. Regards.

Can you confirm that CAA marks as valid that the pressure drops in the NGV in reaction turbine?

Another one i found which is contradicting other answers in BGS is this one: 210590
"The specific fuel consumption is inversely proportional to pressure altitude, at constant TAS." When the correct answer in most questions is that SFC increases/decreases SLIGHTLY with PA decreasing/increasing, so not inversely proportional and not directly proportional.

[flyfly4]

Interference (not unlawful) is 7700 mode A or C? In BGS QB it says mode A and in my book it says mode C.

[Alex Whittingham]

flyfly4, for your carburettor question did you look at the explanation? As altitude increases the air becomes less dense, less mass of air requires less fuel to maintain the mixture.

Concerning 210754 the question is:

"Which of these statements about a reaction turbine are correct or incorrect?

I. The pressure drops slightly across the nozzle guide vanes.
II. The pressure remains constant across the rotor blades."

and we say I is correct, II is incorrect which, given the options, I still think is correct. Again if you look at the explanation we see the suggestion that those that wrote the question believe the NGVs to be slightly convergent which will lead to a slight acceleration and a slight pressure drop. This would explain the answer which does not agree precisely with the Rolls Royce book.

210757 is similar, the explanation is similar.

210590 is:

"Regarding a jet engine:

I. The maximum thrust decreases as the pressure altitude increases.
II. The specific fuel consumption is inversely proportional to pressure altitude, at constant TAS."

'slightly' is not an option, but we would agree, and we say exactly that in the explanation. Never the less if PA increases by 60 units and SFC decreases by 1 unit it still is inversely proportional and so the answer "I is correct, II is correct" is true.

Unlawful interference is A7500, not 7700. From PANS-OPS "If there is unlawful interference with an aircraft in flight, the pilot-in-command shall attempt to set the transponder to Mode A Code 7500 in order to indicate the situation. If circumstances so warrant, Code 7700 should be used instead."

You should ask your training provider for their explanation. Who are they?

I cannot say what EASA/the CAA consider to be correct today, we only know what was said when these questions were queried in the past. We have no real-time feed!

[flyfly4]

Thanks for the reply.

I will check again for all the questions regarding SFC.

Regarding interference, I mean the Interference which is not unlawful. I know code 7700 should be set but in my book it says mode C and in BGS says mode A.

Regards!

[Alex Whittingham]

Interference which is not unlawful? Do you mean lawful interception?

The Mode A/Mode C confusion comes from light aircraft equipment which has a rotary selector that goes OFF/STBY/ON/ALT where ALT in this case means Mode A with altitude reporting but can convey the impression that Mode C exists as a discreet selectable mode. This can also make (badly written) questions confusing because one does not know whether the chap that made the question up is asking you to choose 'Mode A with altitude reporting' or trying to trick you into choosing the wrong mode. Mode C is not available on its own and you cannot select a code, it sends the encoded pressure altitude from either the ADC or the digitiser on the instrument itself. There used to be a Mode B on some equipment as well, and of course there is mode S, a selection usually referred to on the rotary switch just as XPNDR.
http://mutleyshangar.com/reviews/jack/737atc/img/OpencockpitsTransponder.jpg
With the current EASA exams it is always better to go back to the source regulation and you see from my previous post how the requirement is laid out in PANS-OPS, albeit for 7500. It is quite specific "Mode A Code 7500". Yes, altitude reporting would be nice to have and help everybody concerned but that is not the requirement.

I'm afraid I don't know who wrote your book, but they are not helping you.

[flyfly4]

Thank you very much for your detailed answer Alex!

Regarding the question:
The EAT has to be transmitted to the pilot as soon as possible, in case the expected delay is:
10 minutes
5 minutes or more.

BGS says 5 minutes or more
ATPLonline says 10 minutes.

BGS explanation: "The correct answer is 10 minutes but we understand that the examiner has gone for 5 minutes as the answer to this question."
That means that EASA marks as correct 5 minutes?¿


Another:

Minimum Radar Separation on final approach
The minimum radar separation provided between aircraft established on the same localizer course shall be:
(plus additional longitudinal separation as required for wake turbulence)
ATPLonline 3NM
BGS 2.5 NM. (q 100314)

[paco]

Changes of over 5 minutes from the original time should be communicated by ATC as soon as possible.

I wonder if it's the usual bad phrasing?

[Alex Whittingham]

flyfly4,

PANS-ATM
6.5.7.1 An expected approach time shall be determined for an arriving aircraft that will be subjected to a delay of 10 minutes or more or such other period as has been determined by the appropriate authority. The expected approach time shall be transmitted to the aircraft as soon as practicable and preferably not later than at the commencement of its initial descent from cruising level. A revised expected approach time shall be transmitted to the aircraft without delay whenever it differs from that previously transmitted by 5 minutes or more, or such lesser period of time as has been established by the appropriate ATS authority or agreed between the ATS units concerned.

You will see there are two sorts of delay, an initial delay and a subsequent delay.

6.7.3.2.5 Subject to radar system and situation display capabilities, a minimum of 5.6 km (3.0 NM) radar separation shall be provided between aircraft on the same ILS localizer course or MLS final approach track unless
increased longitudinal separation is required due to wake turbulence or for other reasons.

Note 1.— See Chapter 8, 8.7.3.4.
Note 2.— An aircraft established on an ILS localizer course or MLS final approach track is separated from another aircraft established on an adjacent parallel ILS localizer course or MLS final approach track provided neither aircraft penetrates the NTZ as depicted on the situation display.

but if you follow through the reference you find 3.0NM can be reduced to 2.5NM under some circumstances.

8.7.3 Separation minima based on ATS surveillance systems
8.7.3.1 Unless otherwise prescribed in accordance with 8.7.3.2 (with respect to radar), 8.7.3.3 or 8.7.3.4, or Chapter 6 (with respect to independent and dependent parallel approaches), the horizontal separation minimum based on
radar and/or ADS-B shall be 9.3 km (5.0 NM).
8.7.3.2 The radar separation minimum in 8.7.3.1 may, if so prescribed by the appropriate ATS authority, be reduced, but not below:
a) 5.6 km (3.0 NM) when radar capabilities at a given location so permit; and
b) 4.6 km (2.5 NM) between succeeding aircraft which are established on the same final approach track within 18.5 km (10 NM) of the runway end. A reduced separation minimum of 4.6 km (2.5 NM) may be applied,
provided:
i) the average runway occupancy time of landing aircraft is proven, by means such as data collection and statistical analysis and methods based on a theoretical model, not to exceed 50 seconds;
ii) braking action is reported as good and runway occupancy times are not adversely affected by runway contaminants such as slush, snow or ice;
iii) a radar system with appropriate azimuth and range resolution and an update rate of 5 seconds or less is used in combination with suitable radar displays; etc., etc.

You can find these documents online. Your groundschool should have them at least in electronic form and should be able to answer your queries.

[flyfly4]

Thanks a lot alex, :)

[flyfly4]

Contracting states shall not require the authorized agent or pilot-in-command to deliver to the public authorities concerned, before departure of the aircraft, more than some copies of General Declaration, Cargo Manifest and stores list. The numbers of the copies are :

In class we have been told that now its 3 of each. Is it the same for the CAA or we should stick to the old answer?

[Dream2Jet]

Hi Alex or others, whats the difference and best explanation between a spring tab, servo tab and other relevant devices in POF? Thanks.

[Richard007]

Hi all,

I was wondering if anyone could tell me if the Oxford 4th edition Atpl manuals are up to date for the current Atpl exams. I did the exams in 2005 and had to stop training shortly afterwards. I'm thinking about sitting the exams again and finishing up my training. As far as I know I can "self-certify" for the Atpl exams so I want to know that I'm re-learning valid information. If they are not suitable, could someone let me know their opinion on the best study material. I'm 35 now so time is ticking!!! Thanks in advance everyone,

[MaverickPrime]

Folks,

Just a general question. A lot of talk about new changes to exams this year by EASA, its making me a bit nervous. I'm currently with BGS, I'm working through CBT and plan to hit the QB hard before I show up for my first set of exams. What I'm wondering is - are the questions asked on the ATPL exams the same at every CAA venue across the world (I understand things might be different if you sit your exams under a different european regulator). In other words if I'm studying the BGS CBT & question bank and then sit my exams at a different CAA venue than Bristol, will I still be adequately prepared, or are there other things I need to be doing to prepare myself?

There might be an obvious answer to this, but just checking for peace of mind!

[paco]

The questions are different for every candidate - even the person next to you will have different questions and annexes. But they will all come from the same place.

[Alex Whittingham]

It does appear that different Authorities are introducing new questions at different rates, and that many Authorities are less critical than the UK CAA of new questions that are defective. In other words your chances of successfully appealing a defective question may be higher in the UK than elsewhere. In the UK it is normal for a number of papers to be remarked each month following appeals by schools or candidates so that, when a defective question is identified, anyone who got that question 'wrong' according to the marking scheme is credited, whether they appealed in person or not. This usually just leads to a new mark for those that passed, but in some cases can turn a 'fail' into a 'pass'. Where this process would lead to a 'fail' just being recorded as a 'fail' with a higher percentage the UK CAA do not adjust either adjust the marks or notify the affected students.

[Dream2Jet]

Alex, Paco et al, can you advise on the following for the FLight Planning exam pls.

What is PDP and Decision Point Procedure? Thanks.

[7779]

Hi there, been reading this forum for a while. Due to head to bristol this autumn for MOD 1 revision course. Im working through the CBT and am averaging anywhere between 40 & 70% in most of progress tests, I only pass the odd PT on the first try. I was always pretty good at maths so I'm not struggling with the Gen Nav equations as you might assume, just struggling with remembering the sheer amount of info, especially with MET.

I've worked out that I should have at least three weeks between finishing the CBT and going to bristol to practice the question banks. Do you think if I work at the question banks before going to bristol, will it be enough to bring my scores up to a good level? Just worried that I won't be up to standard in time for the exams!!!

[Alex Whittingham]

Everyone has the same worries. Do the coursework, if you don't pass the PT first time, revise, do it again. Go through the question bank on the app or online, once you have seen all the questions try practice exams without a time limit initially, then set the timer. Try and get yourself to a pass standard in all papers. If there are gaps in your understanding we will work on that on the revision course.

You'll find that most of the people with you in the room on day 1 of the revision course have the same doubts and fears - its normal. If you have done the distance learning work and had a reasonable stab at the question bank you should be OK.

[paco]

Just like playing the guitar - speed comes with practice. Every time you do a test, it will be just that bit quicker than the previous one. Just don't try to rush, because your mental focus will be on finishing in time rather than on the material, i.e. in the wrong place.

[7779]

Thanks folks, sounds like I'm more or less on the right track! I would guess that the CBT pushes you hard to ensure that you are well prepared for the exams.

[paco]

That's what it's for...... :)

[RedBullGaveMeWings]

Cold air is denser than warm air, but why does the airflow become warmer and denser at the same time in a shockwave? Is it because of skin friction?

[keith williams]

To understand what is happening we need to look at the basics and work from there.

Density = Mass / Volume, so if the volume of a fixed mass of air increases, its density must decrease. If its volume decreases then its density must increase.

If we take a mass of air and warm it slowly, it will tend to expand. If the air is held within a container it will be unable to expand, so its pressure will increase. We will still have the same mass of air in the same volume, so the density will be unchanged. If we now reduce the volume of the container, the pressure, temperature and density of the air will all increase simultaneously.

If we now take the top off the container the air will be free to expand. As it expands it will take up a greater volume. We will now have the same mass of air in a greater volume, so the density will be lower. The pressure and temperature will also decrease as the air expands. So as the air expanded the pressure, temperature and density all decreased.

A shock wave is an instantaneous pressure increase. So when air flows through a shockwave it suddenly finds itself in an area of higher pressure. This causes the air to be instantaneously compressed until its pressure is equal to that immediately behind the shockwave. This sudden compression of the air causes its volume to decrease, so its density must increase. The sudden compression of the air also causes its temperature to increase. So we have a situation in which the pressure, temperature and density all increase simultaneously.

So passing the air through a shockwave causes it to behave as if it were inside a container which suddenly shrunk in volume.

[RedBullGaveMeWings]

Clear explanation, thanks.

[Ronaldsway Radar]

Hi all

Taking AGK, instruments and ops this coming week. My last 3 so mixed feelings at the moment - been distance studying for 2 years now so looking forward to enjoying some free time again!

Has anybody got some recent feedback on any of these subjects from the exams as I'm aware there was a bit of an issue earlier in the year with ops in particular.

Not looking for questions and answers of course, just hoping to find out if there were any nasty surprises that weren't fully anticipated from the LO's.

Thanks

[Ronaldsway Radar]

Whilst I'm here - Keith, Alex, Paco and numerous others - there has been some excellent support on here over the past few years and I'm sure many have gone on to understand some topics a little bit better thanks to your input. Thank you very much for taking the time to lend your support.

[paco]

A read of doc 965/2012 from EASA would be a good start for ops.

Glad to help, BTW - anything to beat the system :)

[RedBullGaveMeWings]

I am going to ask this question here as I've been unable to post on atpforum.eu due to technical problems.

Hopefully someone who has access to Bristol GS CBT can help me as this is a question in the Grid Navigation Progress Test.

I am having trouble solving this question and don't really understand the last part of the explanation in the CBT.

(Refer to Annex 098-061-001)
Note you will need to print and then plot on this diagram. North Polar Stereographic Chart with a grid overlaid with the Greenwich Meridian. An Aircraft Flies from the geographic North Pole for a distance of 480 NM along the 110° E Meridian, then follows a Grid Track of 154° for a distance of 300 NM. Its position is now approximately:

80°00'N 080°E

I have no problem in solving the first part of the question as it is just matter of subtracting 8° (480 NM/60) from 90° to find the 82°N latitude, however I am not understanding how to get to the final solution and I don't understand the last part of the explanation which says to use the latitude scale to measure this 300 NM but I am provided with no scale.

What am I missing?:sad:

[paco]

300 nm is going to be roughly 5 degrees at that latitude (the cosine is very small) - try a pair of compasses centred on the new location then see which answer fits? :)

[RichardH]

Red Bull you are missing a paper annex which looks like a north PS chart maybe with the scale you require printed on it. You then have to physically plot (on paper) the two position lines both in terms of direction and distance at the end you should be at 80 80 approx. Regretfully I don't have a copy to attach here.

[Alex Whittingham]

Just to double clarify the answer to your last sentence, RedBull, there is no separate scale printed on the chart because you are expected to know that one minute of arc on a great circle is 1NM. Meridians are great circles so if you measure one degree of latitude change along a meridian you are measuring 60NM and, as Paco says, 300NM is 5 degrees of latitude change.

[RedBullGaveMeWings]

I printed the annex paper of course.
I did some research and they key to solving this question was to assume 1cm=100NM.

[Alex Whittingham]

If that worked it was only by chance. There was no scale given other than the meridian. The explanation was:

(Refer to Diagram)

From the North Pole on the diagram the aircraft flies down the 110°East meridian.

The meridians are shown every 10° of longitude.

The distance travelled is 480 NM which is equal to 8° of latitude.

Use the latitude scale to measure the distance flown from the pole down the 110° East meridian.

The aircraft is now at 82°N 110°E.

At this point draw in grid North parallel to the Greenwich meridian and plot a track of 154° Grid from 82°N 110°E.

The aircraft travels 300 NM along this track which is equal to 5° of latitude.

Use the latitude scale to measure this 300 NM, plot it onto the chart and you should find the aircraft will be at or close to 80°N 080°E.

[RedBullGaveMeWings]

I couldn't understand just the last row of the explanation as that was the final point where I was stuck, however now it's crystal clear.

[RedBullGaveMeWings]

Just a couple of quick questions.

I am switching to a Jeppesen CR flight computer and noticed in the manual that it is possible also to calculate so called pressure patterns problems. Since I have not find a lot about it in my ATPL notes, am I right in assuming it is not part of the syllabus?

Second question is, are temp rise questions part of the syllabus?

[n1failure]

Don't bother banging your head against those sort of questions.

Some of them are just written poorly and are quite vague in what they ask for.
There are some ultimately you'll just have to remember.

[paco]

No pressure pattern, but temperature rise, what Jeppesen calls the "new method" of TAS calculation.

[smthngdffrnt]

Hi there!

I´m revising my notes about spins and I don´t find a proper explanation.

Any comment will be very welcome!

Thanks.

[paco]

As with any downgoing wing, the relative airflow comes more from underneath and increases the angle of attack.

[PDR1]

You're no being clear, but if the question is what I think it is:

Dihederal increases the angle of attack (AoA)on the outside wing in yawed flight. So if an aeroplane with dihederal is yawed to the left (left pedal) the AoA of the right wing increases, and the AoA of the left wing decreases - producing a roll moment in the same direction as the yaw. So in principle if an aeroplane is yawed and rolled in the same direction there will be "less lift" (horrible way of describing it) on the down-going wing than there would be if the dihederal wasn't present.

Now you mentioned spinning, but that's a different skillet of sea-bass because in a spinning condition the "down-going wing" is mostly stalled - the loss of lift and increased drag being what produces the autorotating couple. But I'm sure this isn't what you're asking, so could you clarify the question?

[smthngdffrnt]

If describing a force instead of saying "higher angle of attack" is horrible, I think we´ll have to burn all the books about aerodynamics on earth...

Anyways, if you read the title with attention you´ll realize that I´m talking about wings without geometric dihedral. In other words, in case of sideslip, why does the downgoing wing have a higher angle of attack?

I understand this scenario when we have an aircraft with physical dihedral, however, It seems that "I don´t see" the vectors involved when it comes to an aircraft without dihedral.

[PDR1]

If describing a force instead of saying "higher angle of attack" is horrible, I think we´ll have to burn all the books about aerodynamics on earth...


It's a horrible way of describing it because there isn't "less lift" - there is just a spanwise redistrubution of the same amount of lift.


Anyways, if you read the title with attention...


Yes, being sarcastic with people who bother to try to answer vaguely-expressed questions always motivates further responses, doesn't it...:ouch:


...you´ll realize that I´m talking about wings without geometric dihedral. In other words, in case of sideslip, why does the downgoing wing have a higher angle of attack?


It doesn't. Any yaw-roll coupling in aeroplanes with no geometric dihederal comes from other sources - wing-sweep, differential blanketting of inboard wing sections and secondary roll moment of the fin being the most common ones AIUI.

[smthngdffrnt]

That´s not sarcasm. It´s just an objective fact as you were talking about dihedral and the title is clear (without dihedral). On the other hand, you say vaguely-expressed, I say briefly-expressed -Paco got it at first try-.

As far as the technical content of your answer, do you affirm that the relative airflow (downgoing wing in a sideslip) won´t be inclined upwards, increasing its effective angle of attack/lift?

That´s what the books say literally and you say that the amount of lift is the same. Now I understand nothing.

Thank you, PDR1.

[smthngdffrnt]

Paco, I think you are right, but I don´t find any graphic with vectors to see that distribution of forces.

[PDR1]

Not sure why I'm bothering, but anyway.

If flying in balanced straight and level flight with zero yaw and an angle of attack alpha is subjected to a pure yaw (no roll or pitch secondary effects of the yaw control) through an angle beta then the angle of attack of the wing (the whole wing, not one side or the other) will reduce by a factor proportional to cos (beta).

In a real aeroplane the resulting reduction of lift coefficient will make lift less than weight, so the aeroplane will accelerate downwards until it achieves a steady state condition where the angle of descent is equal to alpha * [1-cos(beta)].

At least I think that's it - trying to visualise it in my head because I'm posting this with my phone and don't have a whiteboard handy to sketch the diagram.

But I cannot see any situation where it would be different for the two sides of a wing with no dihederal.

[PDR1]

I did have, but he's noticed that it's missing and has asked for it back...

[Piloto Maluco]

Hi folks,

someone heard about the change of the exams in April ? Apparently 20% will be written?

Thanks

[paco]

In the UK, February. As usual, 1500 new questions, and 2000 reviewed.

[Fouga_GVA]

Hi Paco,

Could you give us more information about what will change in the ATPL in 2017.
What do you mean by written questions ?

[KayPam]

Hello

I would have a question about the computers.
Do they all do the same things ? I have a CRP5 whereas my school recommends an aviat 617.

Are they really used in real life ? (i.e. in flight)
Obviously they are not useful on any modern jetliner, but what about powerful older aircraft ?
I learned tonight most of the computations mine can do, and I was pleasantly surprised with all it can do, and the simplicity of its use (it seemed a bit daunting initially)

Or are they just used during the ATPL exams ?
Is it allowed to have a calculator during the ATPL exams ?
If so, what's the computer for ? (my calculator could easily do everything that the computer does, since it is programmable)

Thank you

[cavok_flyer]

Hello KayPam,

You have to check with your local CAA for which tools you are allowed to bring to the exams. In Germany, you are only allowed to bring to the ATPL exams pens, pencils, ruler, and a flight computer (ie. Aviat 617). They provide notepaper for calculations as well as a REALLY SIMPLE (read: non-programable) caculator. You probably would find the 617 more useful than a CRP5 since it also has MACH numbers on it. Once you pratice with the 617, you have an answer faster than with an electronic calculator esp. wind calculations, PSR & PET are super fast and easy, calculating MACH with IAS and different temperatures is a snap, etc. As for real world application, my IFR FI also flies executive jets and uses his almost daily to double check the caclulations he receives from dispatch.

[paco]

An Aviat 67 is an expensive beast, though extremely well built. If you were going to use a slide computer, you won't get a better one - the AFE ARC 2 would be another good choice.

I still use my whizzie after over 40 years - it doesn't need batteries so no embarrassing silences when the calculator dies :) Also be aware that the electronic ones tend to use the American nautical mile which is a few feet less than the standard one of 6080 feet.

We train with the Jeppesen CR-3 circular flight computer - it is much easier to use than the Dalton/E6B slide thingies, and can be obtained new for around £26 off ebay. As there is a hole through the middle you can put a bit of string through it and use it one handed when you hang it from a suitable place in the cockpit. In our Beavers, there was a convenient hook by the door.

In the absence of the old workbook, which is well out of print, I have done a replacement (PM for details), and we have done an Android app for it as well.

[Alex Whittingham]

Point of order, Paco. Both the American and British Admiralty nautical miles were 6080ft. The 'international nautical mile' is 1852m, just over 6076ft!

[Alex Whittingham]

...and EASA, bless them, define a nautical mile as 1852 km, LO 061 01 05 01 in Annex II to ED Decision 2016/008/R.

[paco]

I'll have to check with the Admiralty manual, but my understanding is that the British version is the one used for calibration and navigation in general, which is correct at 48 degrees of latitude. According to the Dictionary of Military and Associated terms from the US DOD, "The United States has adopted the international nautical mile equal to 1,852 meters or 6,076.11549 feet." That would be at 45 degrees.

That's a loooooong nautical mile, even for EASA! :)

But who cares - the calculators use 6076 - I'd forgotten the number, but you kindly supplied it! :)

[Alex Whittingham]

According to Wiki The US abandoned the longer nautical mile in 1954 and the UK changed in 1970. TBH we still teach 6080ft because (i) its easier to remember along with 3280 and 5080 (ii) the error is only 0.065% (iii) if you use the calculator the conversion is accurate anyway.

[paco]

That about sums it up!

[KayPam]

An Aviat 67 is an expensive beast, though extremely well built. If you were going to use a slide computer, you won't get a better one - the AFE ARC 2 would be another good choice.

I still use my whizzie after over 40 years - it doesn't need batteries so no embarrassing silences when the calculator dies :) Also be aware that the electronic ones tend to use the American nautical mile which is a few feet less than the standard one of 6080 feet.

We train with the Jeppesen CR-3 circular flight computer - it is much easier to use than the Dalton/E6B slide thingies, and can be obtained new for around £26 off ebay. As there is a hole through the middle you can put a bit of string through it and use it one handed when you hang it from a suitable place in the cockpit. In our Beavers, there was a convenient hook by the door.

In the absence of the old workbook, which is well out of print, I have done a replacement (PM for details), and we have done an Android app for it as well.
Could you please explain in which way it would be better ?

More computations available ? (given that any computer can do any multiplication I don't see much more to do beyond that, except of course CAS TAS Mach conversions, and density altitude, and wind computation)

More precision ?

A better build ? (easier to move the sliding circle to an exact position)

(For the record, I wouldn't use any specialised electronic computer, just my general purpose calculator which can do everything when programmed right)

So, what about ATPL exams ?

In any case, thank you paco for all the info you're providing. It looks like you are working for an FTO ?

[paco]

You might want to check that you are allowed to use a programmable calculator.....

That aside, the CR-3 is cheaper and way more logical. It doesn't use a slide, and is based on cosines. The slide rule side is similar to the others, it is true, but it's the wind side that scores - it makes grid navigation a breeze.

http://www.captonline.com/CR3.jpg

In the picture, your true course is 130. Your grid course is shown opposite your longitude, in this case 090 degs opposite 40E.

You can do this a little bit with the CRP-5, but it goes all the way round on the CR-3.

Also, convergency.

http://www.captonline.com/CR32.jpg

180 nm on the outside scale, find the cosine of the latitude, in this case 54 degs N, departure is right opposite (the sine of 36 is the same as the cosine of 54).

Busted! :) I do indeed work for an ATO .

[wingwarrior]

Fellow pilots,

I am an FAA IR/CPL (Irish national), and have spent hours researching different schools for the next step of my training. I plan to commit to a UK-based Distance Learning course in order to maintain my present source of income as a flight attendant. I would appreciate any reviews/recommendations from current/past students/instructors/experts.

I am particularly interested in an updated review of CATS, as the price is enticing but my research is inconclusive as to the consistency and quality of the instruction.

I am looking for an ipad based, offline course that provides high quality animations and consistent textual instruction. Also important to me is the quality of instruction during the brush up courses. While my research indicates that BGS scores highly in all these regards, I would appreciate input of any recent/present CATS/Padpilot users out there so that I can decide which way to fly...

[KayPam]

Hello
I am reading something very weird in my Oxford ATPL books (fifth edition)
In Air law, 10.4 (page192), it is stated that a holding pattern should be flown at M0.83 if at or above FL340.
WTF ? M0.83 is above MMO for numerous aircraft..

Thanks

[tech log]

That's the maximum allowed speed, not a "you must fly this" speed.

[KayPam]

Ok so I guess that's a mistake of my textbook.. "Holding patterns are to be flown at the following speeds :"
Then it proceeds to give a table of speeds including the M0.83 of above.

Another surprising point is that the turbulent conditions speeds are higher than the normal condition speeds. Why would you be allowed to go faster in turbulent conditions ? To go through higher variations of VRTG and get past VNE more easily ?

[tech log]

"ICAO Doc 8168 Vol 1 §6 ¶ 1.3.1 Holding patterns shall be entered and flown at or below the airspeeds given"

Get past VNE more easily - What do you mean by that? Why would you want to exceed VNE?

[KayPam]

Because in turbulent air it is common to see speed increase in unwanted manners.
So i was being ironic, basically.

The usual recommendation for going through rough air is to decrease speed (under vra), not increase the maximum allowable. I dont have my book right now but the max speed increased from 230kt to 280kt when in rough air, which seems absurd.

I will google that icao doc tomorrow

[Sanger]

Hi All

I'm struggling to work these questions out.

1)The altitude of an airfield with an ATZ is given as 350ft, how high will the ATZ be above the airfield?

2)You are flying at 4300ft on a QNH of 1003 under controller airspace which has base of FL45. Are you in controlled airspace?

3)You are travelling at 270knts with a tailwind of 30knts, how long will it take you to travel 150nm?

4)You weigh 95kg, your friend weighs 85kg. Your aircraft has an empty weight of 265kg, how many litres of fuel can tou carry without exceeding your MOTW of 450kg?

Can anyone help me out by showing how to work these out?

[tech log]

1) Trick question. Air Traffic Zones always have a height of 2000ft above the aerodrome. Because it's above an AD with an elevation of 350ft, the height of the ATZ will be 2000ft but it's altitude will be 2350ft.



2) Flight Levels are based off standard QNH of 1013hpa. 1hpa = 27ft.

1013hpa - 1003hpa = 270ft difference.

The pressure setting you are flying via is lower than 1013.

The easiest way to think about this is -

When you move the sub scale knob on the altimeter to the right to increase the value to 1013, the altimeter needle will also increase.

It will increase by 270ft.

4300ft + 270ft = 4570ft pressure altitude = above FL45. You are in controlled airspace.




3) 270kts airspeed + 30kts tailwind = 300kts ground speed.

speed = distance / time therefore time = distance/speed

time = 150nm / 300kts = 30 mins.



4) Pilot and passenger total weight = 180kg.

180kg + aircraft weight 265kg = 445kg.

You can only carry 5kg of fuel. Question asks for it in litres.

The specific gravity SG of AVGAS is roughly 0.72.

5kg / 0.72 = 6.9 litres.

You can only carry 6.9 Litres before infringing on the aircraft's MTOW.

[Dream2Jet]

Hi wingwarrior, I would recommend a look at Calendonian, their notes are good, can highlight them in a PDF which is good, also recommend a BGS login. Will send you a DM on experience of my school.

[KayPam]

Hello
I just received my access to aviationexam databases.

What should we do if the answer to the question is debatable ?
For instance I once had to choose between :
A STAR means standard instrument arrival
B STAR means standard arrival

My book says : STAR means standard (instrument) arrival

I don't care about this particular question, but what should we do in the general case ?
Does this database really contain most of the questions we'll see on the exam day and their correct answer ?

My method will now be to first read the books, and then do the questions (at the end of each book or at the end of each major chapter of that book), dividing my time equally between them : is this a good strategy ?

I would like to get both 90+% and the real knowledge to pass interviews later
And for that I will be working six full months at 25-30 hours per week (have been doing so for already one month)

Maybe subjects should be separated into a "scientific/critical thinking" category (such as flight mechanics) and another "brainless QCM answering" category like air law, and a different method used for each category ?

Thanks for all suggestions, as I hope to be taking my ATPL th exams once in my life, I won't have a trial run.

[Alex Whittingham]

I know you said you didn't care but ICAO DOC 8168, Definitions, gives:

"Standard instrument arrival (STAR). A designated instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, with a point from which a published instrument approach procedure can be commenced."

So your book is not 100% correct by including the brackets. A small point I agree but even with that information you would answer (a). In the general case you can either ask the database provider or your ATO for clarification or check online. I would not say that this was actually debatable as VFR arrival procedures also exist and would fall under the definition given at (b).

[KayPam]

I do care, however, about how I could learn this without reading the complete billions of pages of ICAO/EASA documentation.

Similar question in this topic :
http://www.pprune.org/professional-pilot-training-includes-ground-studies/588955-new-easa-atpl-questions-2.html#post9640592

[rudestuff]

Have a look on YouTube. I found a 5 minute video that explained it all. Once I'd watched it a dozen times.

[paco]

Simple geometry, isosceles triangles. Treat grid nav like variation.

[rudestuff]

Your floor will be littered with sheets of A4 paper covered in circles! Try to get 6 each side - think of the trees.

[RedBullGaveMeWings]

It's easy if you keep in mind there are only 180 degrees in a triangle, so if you know the value of two angles you can easily find the third one. And it's even easier if you consider that you count angles always in a clockwise direction relative to the North being considered—be it Grid North, True North, Compass North or Magnetic North.

Simple, not precise sketches will do it for you, keep it simple. And on some occasions if you draw the sketch accurately with a divider and protractor you'll get to the solution without doing any fancy calculation on your calculator. While I was quite worried about Gen Nav at the beginning of the syllabus, it turned out to be one of my favourite subjects.

[OhNoCB]

360 degree protractor. I would say 8 times out of 10 from what I remember if you drew a circle round the protractor and put the points on accurately you could get the answer from the multi choice options within a few seconds.

[KayPam]

Hello,
I failed to see that in the following question, the gyro north was at 0° initially ! I thought the gyro north was at the real north initially (how stupid am I?)
https://i.gyazo.com/6c17d40997881b4787f31b31be630be9.png

So I started to make a huge fuss about this, including a polar navigation sketch in Google Earth.
Let's not loose it, as it took a bit of time to make :
https://i.gyazo.com/ce5e898881efc970e45a50187450823b.jpg

If anyone would like my explanation as to how the picture is made and what the reasoning behind it is, do not hesitate to ask further clarification.

[iFunFlyer]

XXXX 251020Z 24005KT 5000 NSC 05/03 Q1022 R99/3101//

Can anyone decode, "R99/3101//"?

Thanks

[dimsp81]

Hello!
I was wondering if someone can help me on this question:

You plan to fly from point A (60oN 010oE) to point B (60oN 020oE). The gyro North of the gyro compass, assumed to be operating perfectly, with no rate correction device, is aligned with the true North of point A. The constant gyro heading to be followed when starting from A given that the flight time scheduled is 1h30 min with a zero wind, is equal to:

a)66
b)80
c)76
d)85

Questions:
1)Do we have to draw one of these known diagrams with a circle and grid north or just a just two parallels (010oE and 020oE) are enough?
2)How the solution is affected by the fact that at point A the gyro north is aligned with true north?
3)The two points (A and B) have the same latitude.That means that in order to fly from A to B we have to fly constant TRUE track of 090o?This is a rhumb line?

I would be grateful to anybody who has the will and time to spend some time on this question.

Thanks for reading!

[Alex Whittingham]

1) no
2) It's a straight line track, ie a great circle, the question is effectively asking you the initial great circle track A to B. Given that the initial true track = the initial gyro track, if you hold the initial gyro track on the gyro compass it will get you from A to B, true track will change as the true north reference changes (that's convergency in action) but the gyro will not. This is the strength of gyro navigation in high latitudes.
3) 090 deg true would be a rhumb line but this is not a straight line track, and therefore only relevant in calculating the great circle.

Calculate convergency, conv = ch long sin mean lat = 10 sin 60 (ish) = 8.6 deg,
Conversion angle = 1/2 convergency = 4.3 deg
Rhumb line = 090 deg, therefore initial great circle track = 090 - 4.3 = 085.7 deg
initial great circle track 085.7 deg true therefore grid track = 085.7 deg.
QED
....a bit heavy, though, this is really General Nav, and quite foxy for that.

[KayPam]

Hi
You may (or may not) be interested in plotting circles such as the ones shown on the second link in my post below :
http://www.pprune.org/professional-pilot-training-includes-ground-studies/455580-atpl-theory-questions-48.html#post9648882 (the figure was not modified to fit your case, just consider the 62° parallel and its intersection with the 30W and the 10W meridians)

Then you will be able to see for yourself exactly how this all works in Google Earth

You will be able to see that halfway between, your gyro track of 85.7 gives you a true track of 90° and that your true track upon arrival will be 94.3
Your average true track will be exactly 90°

Hope this clarified the situation as opposed to making it more confused.

[dimsp81]

Thanks for the answer!

The truth is that I am confused because I have seen other solutions that comprise astronomic and transport precession,they get average of them and substract from the rhumb line.
It gives another result,totally different.

Why so different?
If the instructors can't agree on a solution that gives the same result,why do they expect it from the students? :rolleyes:

[KayPam]

And now you got me confused ! :p

It indeed seems like time required to travel should be taken into account.
Except of course if something in the question precludes it. Which does not seem to be the case here.

New answer would be 76

Alex, please ?

[paco]

There's no rate correction device, and the flight time is 90 minutes, or 1.5 hours, meaning 200 kts.....

076, based on -13 (Earth rate in the NH*) and -1 (Transport Wander heading East)**. 90 - 14 = 76.

*15 x .866
**200 x tan lat .32/60

[Alex Whittingham]

You're right that it is more complex than I thought, I took no account of the earth's rotation. Please disregard my answer above, I will think about Paco's solution.

[paco]

You're right, though - what the h*ck is it doing in Ops?

[Alex Whittingham]

My early thoughts are that, if the initial GC track is 085.7 deg true, a starting track of 076 deg G (which is necessarily also 076 deg true) will not fly you either a great circle or rhumb line.

[Alex Whittingham]

OK here we go, for gyro experts to comment on. Paco, I get TW of 9 degrees not 1 degree, I don't understand the 0.32 in your formula. I think if you are going to express TW as a rate the formula is (east west groundspeed*tan lat/60)*hours flown which gives the same answer as working it out as convergency.

Solution:

Calculate convergency, conv = ch long sin mean lat = 10 sin 60 = 8.6 deg,
Conversion angle = 1/2 convergency = 4.3 deg
Rhumb line = 090 deg T, therefore initial great circle track = 090 - 4.3 = 085.7 deg T
This will also be initial gyro heading as they are aligned
Final GC track will be 090 + 4.3 = 094.3 deg T

Assuming first of all for the sake of argument that the great circle track is followed by reference to other instruments (INS?) and the gyro is compensated for latitude the total gyro drift will be:
ER + LN + TW
= ([-15 sin 60]*1.5) + ([+15 sin 60]*1.5) + (-10 sin 60)
= (-13) + (+13) + (-9)
= -9
So the final gyro heading will be 094.3 – 9 = 085.3

Now modifying the above so that we continue to fly the GC track by other means but the gyro is now not compensated for latitude, the total gyro drift will be
ER + LN + TW
= ([-15 sin 60]*1.5) + (0) + (-10 sin 60)
= (-13) + (0) + (-9)
= -22
So the final gyro heading in this case will be 094.3 – 22 = 072.3

By which calculations we can see that flying a constant gyro heading/track is not going to follow the shortest (great circle) route. Is it true that flying the ‘average gyro heading/track’ will still get us from A to B by a curved track lying to the north of the great circle? I think so.

If so the ‘average’ to approximate to the GC track without latitude nut correction is (085.7+072.3)/2 = 079 deg

I can't immediately see logically why any calculations should be based on gyro corrections applied to the rhumb line track as we are after the shortest path but, interestingly, if you follow the same argument through and try and fly a rhumb line track by other means the initial true and gyro headings would be 090, the final true heading would be 090, gyro errors would be the same -22 so final gyro heading would be 068, and the average gyro track also 079. This is because the average great circle track is 090, and by averaging out initial and final gyro headings on a great circle track we average out the 'great circle elements' and arrive at the same answer. At one level not surprising because we would not expect to find two constant gyro headings/tracks between two points.

[paco]

the .32 was supposed to be the tan of 60, at least that's what the internet site I used said :).


Multiply by the groundspeed and divide by 60 was the formula for TW.

G/S x tan lat
60


However, having used a real calculator this time :), the tan lat is 1.73, so that ends up with 5.77 or 6 degrees for government work :)

As it is minus because you are going E, apply to the -13 for the apparent wander to get -19, subtract from 90 to get 81, answer B

[Alex Whittingham]

its a correction per hour, so you need to multiply 5.77 x 1.5 = 8.66. Same as the convergency, because its the convergency that causes TW.

I'm guessing you had put your calculator down by the time you said 90 - 19 = 81!

[paco]

Duh!!!!! Yep!

Not enough blood in the coffee stream.....

But sorted in the end!

[KayPam]

So .. 71 and that is answer (a+c)/2 ? :p

[Alex Whittingham]

Well I think 079, but I'm open to comments

[KayPam]

Just got that exact question in AvExam

76 was their answer

Or.. if you're on a transoceanic flight you'll most probably have a computer able to that computation for you :p

[Alex Whittingham]

and what was their explanation?

[KayPam]

How the are we supposed to guess if they're talking about wake turbulence category or approach category ?
https://gyazo.com/26a4609ce71ad40482b07a94aed9ca46
https://i.gyazo.com/e06e9a296a75cb43c438a49046dbe357.png

[KayPam]

It resembles the one I had however everybody will use some variation of that to get the right answer
https://i.gyazo.com/526f9f0281c28855d54cdf5c004ee547.png

[Alex Whittingham]

ah their earth rate is different to mine, 19 deg rather than 13 deg. I copied Paco for that figure - I'll check it.

.... not multiplied by 1.5...

earth rate is 19.5 deg, amended total drift is 19.5 + 8.7 = 28.2

and whether you apply it to the great circle or rhumb line tracks the average is 076. Agreed.

I really shouldn't attempt these calculations!

[KayPam]

And now that I have finished comms, ops, air law and half of instruments questions on avexam, I do realise that it is actually possible to learn the answers to the questions.

I could not believe that one could remember thousands of pieces of data, but even I with a rather bad memory, the answers that can't be figured out by understanding and thinking can very well pop up in my mind because I just remember having seen them.

Which is a bit frightening.... as well as satisfactory because, you know, I have to pass my exams in a short time :p

[paco]

"I really shouldn't attempt these calculations!"

Neither should I :) Back to sleep....

[Alex Whittingham]

What is even more embarrassing is that the question has been in our database since 2011, and I didn't look.

[paco]

LOL!! I wonder if it is still in the real one? Maybe I will ask!

[dimsp81]

I need your help on the following questions-sentences.
Please,correct me if I am wrong!


1)The two points are on the same parallel of latitude (60o).The part of parallel of latitude that connects them is a rhumb line since it cross the meridian of 10 and 20 degrees of longitude at the same angle (which is 90 degrees).
Do you agree?

2)An aircraft that will fly from A to B (eastward direction),will have a constant TRUE TRACK of 90.


3)The gyro compass is aligned on the point A with TRUE north.So,when the trip starts the gyro compass shall indicate 090 (since there is no wind,right).But as the aircraft flies due to precession the indication of gyro compass is altered.
Do you agree?

4)In order to fly on a constast gyro track we have to alter the TRUE HEADING in the beginning of the trip by the half of the precessions?


Thanks for your time!

[Alex Whittingham]

1) yes
2) No. A true (and complete) statement would be "An aircraft can follow the rhumb line track A to B, in which case its true track would be a constant 090 deg, but the path will be curved. It can also take the shortest straight line route, a great circle, in which case the intitial true track will be less than 090, its final true track greater. The aircraft could also take any number of curved tracks other than the rhumb line between A and B."
3) See above. This is correct assuming you try to follow a rhumb line path, but why would you?
4) Will think about this. It is probably true, but your true heading will represent neither the rhumb line nor great circle track. The aircraft will follow a curved path to the north of the great circle.

[keith williams]

The aircraft will follow a curved path to the north of the great circle.

I do not believe that the above will always be the case.

At the Equator there will be no ER or TW, so you will flt along the Equator.

When going west in the northern hemisphere at a ground speed equal to the rotational speed of the Earth at that latitude, the TW will be equal and opposite to the ER, so there will be no wander. This means that you will fly along the parallel of latitude on a 270 true heading.

If you fly west at any higher ground speed the TW will be greater than the ER, so your track will be south of the Parallel of latitude.

I could be wrong of course.....this age-induced brain fade is a terribly sneaky creature!

[Alex Whittingham]

You are right, Keith. Depending on hemisphere and direction of travel the constant gyro track could be north or south of the great circle. I only meant that, in this case, it ran to the north.

[KayPam]

https://i.gyazo.com/a2658fc2c278618ab06bd716ebb829d0.png
Doesn't it rather depend on the latitude for which the compass was made ?

By the way, suppose I buy a compass for 45N and go use it at 45S : won't it be totally upset and not horizontal ?
How can you have a compass fit to use from -45S to 60N, an amplitude which many long haul aircraft have ? (I know they have real means of measuring heading, but there must be an is a standby/emergency compass in these aircraft as well)

Thanks

[Alex Whittingham]

It does, there are compasses made specific to hemisphere but I have only been able to find references to 'orienteering' style compasses. I concluded that aircraft compasses are not compensated for hemisphere but cannot actually confirm that, its just not mentioned anywhere I can find. It makes sense, though.

[keith williams]

This is an example of a question which requires the candidate to do a little bit of deductive work to understand what the author was really asking. The question does not actually say that the compass has been set for any particular latitude, so it is probably best to start by ignoring this possibility. In this case Option A is correct.

If however the compass had been set for some latitude other than zero, then as we move away from the Equator, we would expect the errors to decrease until we reached the latitude for which the compass had been set. The errors would then increase gradually as we moved beyond that latitude. In this case the correct option would be “Decrease then increases”. This is not an option, so we can reasonably deduce that the author of the question did not intend us to employ that interpretation.


This subject was discussed in a thread in the PPL Forum some time ago, and the discussion included how compasses are balanced for different latitudes. Some contributors argued that aircraft compasses are not balanced in this way, but an aircraft compass manufacturer provided the following statement:


I don't know if this will settle your argument, but basically you are both correct. The card assembly is balanced for the vertical component of the earth's flux lines based upon the surveyed strength by NOAA for a given latitude and hemisphere. A small weight is applied to level the display level, non-accelerated flight. The pendular design of the card assembly helps minimize (but not eliminate) the dip errors when turning and accel/decal environments. Hope this helps.

Gil Stone
President
Airpath Instrument Company

The thread becomes rather long and dreary, with much argument about what PPL students should and should not learn, but for those who wish to read it the link is:


http://www.pprune.org/private-flying/543156-ppl-exam-compass-errors.html?highlight=blob+solder

[KayPam]

I suggest we just forget about the usefulness of this question in any serious flying context.. I've flown once with a directional gyro failure. At this time, I had no idea about compass errors but that did not stop me from navigating precisely with it.

I thought that the error was linked to the mass (compensating the dip) lagging behind the axis, isn't it?
I read your post in the linked topic, and you raised a good point : if there was no dip compensating mass, but just a mass well below the C of G, then you're right, the compass will have an "attitude angle" and dip towards the pole, hence the C of G will no longer be on the axis, hence turning/acceleration errors.

However with a non dip compensated compass, these errors should be inferior to those of a dip compensated one ? (this is suggested by Gil Stone's post but rephrased)

And finally Gil Stone tells us that some compasses will use both solutions : pendular design + a supplementary small weight to optimize the compass for a certain latitude ?

Related pic, for the lolz (it is simulation because I could not find it in a real environment)
Emergency/standby compass of an A320
http://www.flightsimlabs.com/index.php/a3xx-master-series-a320-3/#

[keith williams]

Without any form of dip compensation the compass will suffer the full effects of the dipped lines of magnetic force. This will reduce the accuracy of the compass and further reduce the range of latitudes throughout which the compass would be usable.

Adding the pendulous suspension system will reduce the dipping effect thereby improving both accuracy and usable range of latitudes. But because the dipping is not completely eliminated, the pendulous suspension system introduces the turning and acceleration errors.

Adding a balance weight which is appropriate for a given latitude will eliminate the dipping completely, provided the aircraft remains at the latitude. This will also further reduce the acceleration and turning errors. If the aircraft is moved from that latitude some (reduced) degree of dipping will occur and this in turn will increase the acceleration and turning errors.

So it could be argued that by adding pendulous suspension and balance weights, the compass will achieve the best compromise between accuracy, usable latitude range, acceleration errors and turning errors.

[dimsp81]

Can someone help?
Why,if there is no wind and astronomic precession,if we have a constant gyro heading we will follow a great circle?

Please,as simple as it gets...

Thanks in advance!

[KayPam]

I recommend using google earth for this kind of questions.

[dimsp81]

I had it but I unistalled it since I didn't use it.
Will it really help of it will confuse?Does it have features that will really help?

[KayPam]

Well, onto your question now.
You can visualise that a perfect gyro will remain in a constant direction. When you move parallel to the direction of this gyro, the earth surface will actually curve under your feet and you will actually be travelling in a plane (not airplane, a mathematical plane in space) formed by the direction of the gyro and a vector that is the projection of the gyro axis on the earth surface

Use the distance measurement tool to visualise it.

I can't personnally tell you more, you have three options :
- Not care and just learn the answer
- Try to think in space, wonder why you couldn't follow a small circle (intersection of a plane with any part of a sphere's surface), use a pencil and orange (or football)
- Wait for a better explanation here

When thinking and experimenting with a pencil and a football, it looks like it's possible to follow a small circle..

[keith williams]

The short answer to this question is that when we fly along with a constant Gyro Heading set, but no Astronomic Precession, the rate at which the Transport Wander changes the direction of flight, is exactly the same as the rate at which a great Circle track would change. So we are flying along a Great circle track.


The rather longer explanation is provided below.

A google search for “Astronomic Precession” reveals an explanation which concerns how the axis of rotation of the Earth describes a circular motion over a period of approximately 26000 years. This is obviously not the interpretation intended by the author of the question.

In this question Astronomic Precession is intended to mean Earth Rate Gyro Wander. It is caused by the facts that the Earth rotates about its spin axis and the Meridians converge towards the Poles. The equation for Earth Rate Wander (ERW) is:

ERW = 15 x Sin Latitude in degrees x time in hours

The number 15 is in this equation because the Earth rotates through 15 degrees of longitude during each hour. So for any given time period the equation can be restated as:

ERW = Change in longitude x Sin Latitude.

The condition of “with no astronomic precession” can be achieved for the purposes of this question by assuming that the Earth has stopped rotating. Or perhaps more realistically by designing a Latitude Nut system which automatically adjusted itself for changes in latitude. Either of these solutions would eliminate Astronomical Precession (ER) but would leave Transport Wander (TW) unchanged. The equation for TW is:

TW = East-West ground speed x time of flight x Sin Latitude.

East-West ground speed x time of flight = Change of longitude, so the equation can be rewritten as:

TW = Change in longitude x Sin Latitude…………………..Equation 1.


Great Circles have the following properties:

1. All Great Circle form straight lines on the surface of the Earth and have their
centres at the centre of the Earth.
2. All Great Circles which run in a true North-South direction cross the Parallels of
Latitude at a constant angle of 90 degrees.
3. The Equator is the only Great Circle which runs in a true East-West direction, and
this crosses all of the Meridians at a constant angle of 90 degrees.
4. All other Great Circles cross the Meridians at angles which gradually change as we
move around the circle.

So why is that Great Circles running other than north-south or east-west do not cross the Meridians at a constant angle? The reason of course is that the Meridians are parallel to each other only at the Equator, then converge as latitudes increase towards the Poles. So any straight line (Great Circle) running in a direction other than due north-south or due east-west, must cross successive Meridians at different angles. We can see this if we look at the equations for convergence of the Meridians and the Conversion Angle which defines the direction of the Great Circles.

Convergency = Change in longitude x Sin Latitude

And

Conversion angle = ½ Convergency = ½ Change in longitude x Sin Latitude

The change in direction of a Great Circle track between two points is twice the conversion angle, so:

Great Circle direction change = Change in longitude x Sin Latitude……Equation 2

So we now have:

Equation 1…….Transport Wander = Change in Longitude x Sin Latitude.
Equation 2…….Change in great circle track = Change in Longitude x Sin Latitude

This means that the rate of change of the Great Circle Track between two points is equal to the rate of Transport Wander. So as we fly along with a constant Gyro Heading set, the rate at which the Transport Wander changes the direction of flight, is exactly the same at which a great Circle track would change. So we are flying along a Great circle track.

[KayPam]

Could someone tell me the truth about NAT time periods ?
I know the numbers : daytime is Europe to America and is from 1130 to 1900 UTC, crossing 30W
From Paris to 30W there is about 2300km which would be about a three hour flight.
So takeoff from Paris would be between 0830 and 1600 UTC, that is between 930 and 1700 local time.
Maybe a tad earlier when accounting for the winds

So why the f would my book say that westbound flights take off early in the morning ??
When in facts they seem to be taking off all day !

And regarding the eastbound flights, validity is given between 1 and 8 UTC at 30W.
So 3 hours later you're between 4 and 11 UTC in Paris. Which is 5 to 12 local time.

There is no police working at such an early time is paris !

Thanks !

[RedBullGaveMeWings]

Indicated airspeed (as read on the on the airspeed indicator) will:

A - increase in tailwind
B - increase in headwind [I answered this]
C - decrease in tailwind
D - remain unchanged in headwind and tailwind [this is correct]

Who the hell writes this question? Is EASA trolling us really hard?!

/rant

[keith williams]

RedBullGaveMeWings.

I suspect that you are reading the question as meaning something like " a sudden increase or decrease in headwind or tailwind" or "The sudden onset of headwind or tailwind". But the question does none of these things.

It simply asks how being in a headwind or tailwind will affect your IAS. What they want you to know is that an aircraft in flight has no way of knowing what the wind is unless of course the wind suddenly changes. In a steady headwind or tail wind, the IAS will be unaffected.

It would of course hav e helped if they had said that the wind was steady.

[RedBullGaveMeWings]

It would have definitely helped, I was thinking about a windshear scenario. Maybe, due to English not being my first language, the wording I didn't let me catch that.

[Alex Whittingham]

It's not you RedBull, the question is completely unclear. Answer (b) is correct for microburst type scenarios and (d) for steady or slow-changing conditions. In correct English you would also use the indefinite article, for instance "increase in a tailwind". This question was probably written by someone who also does not have English as a first language.

[KayPam]

So, I am taking my first exams in Toulouse the day after tomorrow.
Air Law, ops proc, communications, and I am consistently scoring 90-100% on aviation exam.

Could I encounter many new questions or not ?

Thanks

[KayPam]

There were indeed questions that I suspect were new.
Nothing terrible.. I was uncertain about some answers but got my 75% in all exams.

Real score might be lost in the French DGAC system forever (in which case the exam lady told me that airlines could do with my school's final tests results, which would be VERY favourable :p)

[SeventhHeaven]

Ah yes, the famous high quality french education system, right?

Airlines don't give a toss about your ATPL scores - They will however want you to prove how many sittings it took you (e.g. ryanair).

[RedBullGaveMeWings]

I am going through Instruments questions and there's one I really don't understand EASA's reasoning. And I think the difference between inner and outer loop are fairly clear.

In an autopilot system, the flight path modes are:

1) Pitch attitude hold.
2) IAS and Mach speed hold.
3) Altitude hold.
4) Glide intercept and track.

The combination regrouping all the correct statements is:

A) 4 [my answer]
B) 2, 3, 4 [corect answer]
C) 3
D) 1, 2, 3, 4

4 is pretty clear, but I don't understand what 2 and 3 have to do with the flight path. Altitude is a barometric setting which changes with meteorological conditions from place to place, and we can maintain a speed also during a climb or descend anyway. For example, if a plane slows down on an ILS, RoD decreases and vice-versa to stay on the path to the runway.

[SeventhHeaven]

Have you had a look at www.TheAirlinePilots.com :: View topic - Questions on Autopilot (http://www.theairlinepilots.com/forum/viewtopic.php?t=958) ? That website if great for quickly skimming common questions and topics.

In my opinion, IAS and altitude hold are very clearly properties of the flight path - You're trying to maintain a certain 3dimensional profile.

Holding the pitch attitude says nothing about the 3D flight path, just something about how the aircraft is oriented.

[RedBullGaveMeWings]

My idea of "flight path" is a line, straight or curved, fixed in space, independent of barometric pressure(altitude) and speed.

I know that site, I'll give a look at that thread.

[RedBullGaveMeWings]

Ok I understood why Altitude Hold controls path according to the question, to a certain extent. Moving the subscale moves only the pointers on the altimeter but the aircraft keeps flying at that same pressure outside. At least with the autopilot taken in consideration in the exam. However, I still disagree with it. Pressure levels change, a flight path would not.

[KayPam]

RedBullGaveMeWings
It seems like you could just translate flight path mode into outer loop and then you would be completely all right
Ah yes, the famous high quality french education system, right?

Airlines don't give a toss about your ATPL scores - They will however want you to prove how many sittings it took you (e.g. ryanair).

The ATPL exams are not included in the French education system :p

They really do not give a toss ? I heard flybe wanted 90% minimum.

[SeventhHeaven]

They don't care about your ATPL scores, because they know everybody with half a brain should be able to get 90%+ with the way the current exams are set up.

It's not that 95% average makes you look clever/good, it's that having 80% and a resit makes you look silly. If you know what I'm trying to say with that?

[HEJT2015]

With regards to getting a 90+% average in the ATPL exams and new questions frequently popping up, which question bank would you most recommend to use? Or even a combination..?