ATPL theory questions
Joined: Feb 2018
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From: House with chimney
Hi all this is my first post here and I hope it is the right topic.
Here is the situation...I am starting to study for ATPL and found that there is Oxford NPA29 1st edition after 6th edition that was before that one.
Does anybody know what is the exact difference between those two? Iam looking to buy paper bundle and just want to make sure that I Will study current sylabus. There is a lot of different used books on ebay but I don’t want to invest in them if there is too big difference.
Any coments and advice?
Thank you all in advance!
Here is the situation...I am starting to study for ATPL and found that there is Oxford NPA29 1st edition after 6th edition that was before that one.
Does anybody know what is the exact difference between those two? Iam looking to buy paper bundle and just want to make sure that I Will study current sylabus. There is a lot of different used books on ebay but I don’t want to invest in them if there is too big difference.
Any coments and advice?
Thank you all in advance!
Joined: Jun 2014
Posts: 666
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From: Earth
AGK is difficult at the start, and for me it was the worst, but it ended up being one of my highest. If you start getting your mind melted over what material the inner workings of a shunt wound generator are made of you are doomed. It's both not required knowledge and will eat up a whole day's worth of study for no benefit whatsoever.
Know where the goods are and what topics are really going to get you the marks.
Know where the goods are and what topics are really going to get you the marks.
Joined: Jan 2011
Posts: 660
Likes: 20
From: England
answers to new questions
Question 1.
In a fully powered flying control system the cockpit controls are connected to the pilot valves. The pilot valves control the flow of pressurised fluid to and from the actuators, thereby exerting very large control forces onto the control surfaces. These forces are so large that the aerodynamic loads cannot be fed back through the system. So there is no aerodynamic feedback, which means that servo tabs cannot be used. The term Servo Valve is just another name for the Pilot Valves. So taking the above into account the only correct answer is Servo Valves.
Question 2.
This one requires a bit of thought. If we enter ground effect at CONSTANT PITCH ATTITUDE the ground will reduce down wash, thereby increasing our ANGLE OF ATTACK. This will in increase cl thereby increasing lift. But the reduced down wash will decrease cdi thereby decreasing drag. But the question specifies CONSTANT ANGLE OF ATTACK. To achieve this we must push the nose down to decrease PITCH ANGLE such that we have CONSTANT ANGLE O F ATTACK. In this situation we we have no increase in Cl, but the reduced down wash will decease the cdi. Taking the above into account the only correct answer is induced drag decreases.
Question 3.
Any worthwhile book dealing with high speed flight will include diagrams showing the way CL and CD vary when accelerating through the transonic speed range. The diagram for CL will show that it increase at speeds just above Mcrit, it then decreases until increasing slightly just before Mcdr, before decreasing again. The overall effect is a decease, but the best option in this question is that CL varies with Mach Number.
In a fully powered flying control system the cockpit controls are connected to the pilot valves. The pilot valves control the flow of pressurised fluid to and from the actuators, thereby exerting very large control forces onto the control surfaces. These forces are so large that the aerodynamic loads cannot be fed back through the system. So there is no aerodynamic feedback, which means that servo tabs cannot be used. The term Servo Valve is just another name for the Pilot Valves. So taking the above into account the only correct answer is Servo Valves.
Question 2.
This one requires a bit of thought. If we enter ground effect at CONSTANT PITCH ATTITUDE the ground will reduce down wash, thereby increasing our ANGLE OF ATTACK. This will in increase cl thereby increasing lift. But the reduced down wash will decrease cdi thereby decreasing drag. But the question specifies CONSTANT ANGLE OF ATTACK. To achieve this we must push the nose down to decrease PITCH ANGLE such that we have CONSTANT ANGLE O F ATTACK. In this situation we we have no increase in Cl, but the reduced down wash will decease the cdi. Taking the above into account the only correct answer is induced drag decreases.
Question 3.
Any worthwhile book dealing with high speed flight will include diagrams showing the way CL and CD vary when accelerating through the transonic speed range. The diagram for CL will show that it increase at speeds just above Mcrit, it then decreases until increasing slightly just before Mcdr, before decreasing again. The overall effect is a decease, but the best option in this question is that CL varies with Mach Number.
Last edited by keith williams; 30th June 2018 at 18:32.
Joined: Jan 2014
Posts: 164
Likes: 6
From: UK
Ok so came across this today in a Met practice:
"If the QFE, QNH and QFF have the same value,
a)The 1013.25hPa level must at MSL
b)The airport must be at MSL
c)The conditions must be as in the ISA
d)The airport must be at MSL and the conditions must be as in the ISA"
The answer given is b). However I chose d) for the following reason:
We know QFE=QNH=QFF. We also know that a measurement of QFE is used to calculate QNH using the ISA standard lapse rate and QFF is calculated using the actual lapse rate per unit of height. Then it stands to reason that in this condition, if QFE was to vary then QNH would remain equal to QFF. Say for example QFE was then taken at height 'Z' above the airfield, and the lapse rate conditions on the day = LR1 and ISA standard lapse rate = LR2.
QFF = QFE+(LR1*Z), QNH = QFE+(LR2*Z).
If QFF = QNH then QFE+(LR1*Z) = QFE+(LR2*Z)
cancelling for QFE and Z gives LR1 = LR2
hence, Lapse rate conditions on the day = ISA Standard Lapse Rate.
In answer b) I accept that it is not a wrong answer per say, however because QNH and QFF by definition are calculated, then surly d) is the more valid answer?
"If the QFE, QNH and QFF have the same value,
a)The 1013.25hPa level must at MSL
b)The airport must be at MSL
c)The conditions must be as in the ISA
d)The airport must be at MSL and the conditions must be as in the ISA"
The answer given is b). However I chose d) for the following reason:
We know QFE=QNH=QFF. We also know that a measurement of QFE is used to calculate QNH using the ISA standard lapse rate and QFF is calculated using the actual lapse rate per unit of height. Then it stands to reason that in this condition, if QFE was to vary then QNH would remain equal to QFF. Say for example QFE was then taken at height 'Z' above the airfield, and the lapse rate conditions on the day = LR1 and ISA standard lapse rate = LR2.
QFF = QFE+(LR1*Z), QNH = QFE+(LR2*Z).
If QFF = QNH then QFE+(LR1*Z) = QFE+(LR2*Z)
cancelling for QFE and Z gives LR1 = LR2
hence, Lapse rate conditions on the day = ISA Standard Lapse Rate.
In answer b) I accept that it is not a wrong answer per say, however because QNH and QFF by definition are calculated, then surly d) is the more valid answer?
Joined: May 1999
Posts: 1,846
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From: Bristol, England
1. If QFE = QFF then the measured pressure at the aerodrome is the same as the actual sea level pressure (near as it can be calculated). If the pressures are the same and the location is the same then the aerodrome must be at sea level.
2. QNH pressure is the sea level pressure calculated back from the observed QFE using ISA lapse rate and the known aerodrome elevation above msl.
3. That's going to come out to the same as QFE as we have already established that the airfield is at sea level, there is no elevation above msl and therefore no difference between QFE and QNH.
So what if the atmosphere was other than ISA? The first statement still stands, it doesn't depend on temperature or lapse rate. The last statement still stands as there is still no elevation above msl. Neither are dependant on ISA lapse rates.
2. QNH pressure is the sea level pressure calculated back from the observed QFE using ISA lapse rate and the known aerodrome elevation above msl.
3. That's going to come out to the same as QFE as we have already established that the airfield is at sea level, there is no elevation above msl and therefore no difference between QFE and QNH.
So what if the atmosphere was other than ISA? The first statement still stands, it doesn't depend on temperature or lapse rate. The last statement still stands as there is still no elevation above msl. Neither are dependant on ISA lapse rates.
Joined: Jan 2014
Posts: 164
Likes: 6
From: UK
1. If QFE = QFF then the measured pressure at the aerodrome is the same as the actual sea level pressure (near as it can be calculated). If the pressures are the same and the location is the same then the aerodrome must be at sea level.
2. QNH pressure is the sea level pressure calculated back from the observed QFE using ISA lapse rate and the known aerodrome elevation above msl.
3. That's going to come out to the same as QFE as we have already established that the airfield is at sea level, there is no elevation above msl and therefore no difference between QFE and QNH.
So what if the atmosphere was other than ISA? The first statement still stands, it doesn't depend on temperature or lapse rate. The last statement still stands as there is still no elevation above msl. Neither are dependant on ISA lapse rates.
2. QNH pressure is the sea level pressure calculated back from the observed QFE using ISA lapse rate and the known aerodrome elevation above msl.
3. That's going to come out to the same as QFE as we have already established that the airfield is at sea level, there is no elevation above msl and therefore no difference between QFE and QNH.
So what if the atmosphere was other than ISA? The first statement still stands, it doesn't depend on temperature or lapse rate. The last statement still stands as there is still no elevation above msl. Neither are dependant on ISA lapse rates.
Joined: Jun 2018
Posts: 22
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From: EU
Are SRA and PAR approaches commonly used in Europe?
I just finished reading the ICAO Doc 9432 which wasn't updated since 2007. How common are SRA and PAR approaches these days? Are they still practiced anywhere in Europe? Thanks!
Joined: Jun 2018
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From: EU
Why there are so many approach lighting systems ?
Why not just have only 2 or 3? What's the point of having such and such amount of lights with such and such displacement from each other? What's the PRACTICAL application of each lighting scheme? I mean, do they really help pilots in a different kind of way?
Picture url:
image.ibb.co/fvbhRy/1.jpg
Picture url:
image.ibb.co/fvbhRy/1.jpg
Joined: Apr 2014
Posts: 5
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From: Mexico
Hello everyone,
Just stumbled upon the E ( LO ) 2 Chart. The standard parallels for the chart are at 37º and 65º!
If the maximum latitude range for a Lambert Conformal Conic Chart is 24º ( of which the Standard Parallels should be at no further spread than 16º ) then what kind of corrective calculations must be made for this chart? Or am I missing something?? Can't get my head around it
Thanks everyone!
Just stumbled upon the E ( LO ) 2 Chart. The standard parallels for the chart are at 37º and 65º!
If the maximum latitude range for a Lambert Conformal Conic Chart is 24º ( of which the Standard Parallels should be at no further spread than 16º ) then what kind of corrective calculations must be made for this chart? Or am I missing something?? Can't get my head around it
Thanks everyone!
Last edited by erikfj; 16th August 2018 at 06:03.
Joined: Apr 2014
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From: Mexico
Joined: Oct 2017
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From: UK
erikfj,
Here's the response from my colleague:
Here's the response from my colleague:
The standard parallel separation quoted is the ideal separation for maximum accuracy of detail.
There is no correction to apply for the SP’s being other than ideal because the scale depicted is absolutely correct for that chart.
There is no correction to apply for the SP’s being other than ideal because the scale depicted is absolutely correct for that chart.
Joined: May 1999
Posts: 1,846
Likes: 4
From: Bristol, England
That doesn't sound quite right. The quoted maximum SP separation is to ensure that scale expansion and contraction does not exceed 1% (from memory) and the implication must be that, if a larger SP spacing is chosen scale expansion and contraction exceeds 1%. Its nothing to do with 'accuracy of detail'. The scale is not 'absolutely correct', it is approximate, unless the large projection used to generate E(LO)2 is compensated for by having different, more accurate, scales quoted when sections of the projection are taken, more accurate for their latitude with respect to the SP. Still they will not be 'absolutely correct', only approximations.
Joined: Apr 2004
Posts: 734
Likes: 10
From: London, GB
Originally Posted by 177
I just finished reading the ICAO Doc 9432 which wasn't updated since 2007. How common are SRA and PAR approaches these days? Are they still practiced anywhere in Europe?
In UK a PAR talkdown can be done at over 20 military aerodromes but it is unavailable to most civil pilots. Elsewhere in Europe, perhaps in Germany or Sweden, it may be possible at one of the joint civil–military aerodromes.
SRAs can still be done at about two dozen aerodromes in UK although only a handful offer half-milers. Details in AIP.
Originally Posted by 177
Why there are so many approach lighting systems? Why not just have only 2 or 3?
Originally Posted by 177
What's the PRACTICAL application of each lighting scheme? I mean, do they really help pilots in a different kind of way?
For a pertinent technical report from the FAA's Airport Technology Branch see Reduced Approach Lighting Systems (ALS) Configuration Simulation Testing (DOT/FAA/AR-02/81; Gallagher, DW. Jul 2002). Here is the abstract:
Originally Posted by DOT/FAA/AR-02/81
The availability of Global Positioning System (GPS) approaches has already increased the number of runways capable of handling Instrument Flight Rule (IFR) approach operations. A major factor in upgrading the instrument capability of these runways is, and will remain, the need for installation of many new approach lighting systems (ALS). Therefore, it has become necessary to re-evaluate the present standard systems to identify possible means by which installation, operation, and maintenance costs can be reduced.
In an effort to reduce the overall length of ALS's, this report describes the methods, using simulation, by which the minimum visual cues with respect to length of an ALS is needed by pilots during an approach at Category I minimums. The current US standard is the 2400-foot-long Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights (MALSR). Subject pilots evaluated ten different length configurations and were given questionnaires for each configuration flown.
The results indicate that shortening the system to a length of 1600 feet was not acceptable. Shortening the system to a length of 1800 or 2000 feet may be conceivable if enhancements to the visual segment portion of the system (i.e., additional steady burning barrettes at 1600,1800, and/or 2000 feet) would be considered. Shortening the system to a length of 2200 feet will only provide minimal reduction in ground area required and result in virtually no benefit in reduced equipment or power requirements.
In an effort to reduce the overall length of ALS's, this report describes the methods, using simulation, by which the minimum visual cues with respect to length of an ALS is needed by pilots during an approach at Category I minimums. The current US standard is the 2400-foot-long Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights (MALSR). Subject pilots evaluated ten different length configurations and were given questionnaires for each configuration flown.
The results indicate that shortening the system to a length of 1600 feet was not acceptable. Shortening the system to a length of 1800 or 2000 feet may be conceivable if enhancements to the visual segment portion of the system (i.e., additional steady burning barrettes at 1600,1800, and/or 2000 feet) would be considered. Shortening the system to a length of 2200 feet will only provide minimal reduction in ground area required and result in virtually no benefit in reduced equipment or power requirements.
Originally Posted by dook
The standard parallel separation quoted is the ideal separation for maximum accuracy of detail.
See also p 91 (and footnote 24 re the figure Alex mentions on scale error) in Deetz CH, and Adams OS. 1934. Elements of map projection with applications to map and chart construction (4th ed): U.S. Coast and Geodetic Survey Spec. Pub. 68. (PDF):
Originally Posted by Deetz and Adams (1934, p 91)
In general, for equal distribution of scale error, the standard parallels are placed within the area represented at distances from its northern and southern limits each equal to one-sixth of the total meridional distance of the map. It may be advisable in some localities, or for special reasons, to bring them closer together in order to have greater accuracy in the center of the map at the expense of the upper and lower border areas.
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From: Mexico
Originally Posted by Deetz and Adams (1934, p 91)
In general, for equal distribution of scale error, the standard parallels are placed within the area represented at distances from its northern and southern limits each equal to one-sixth of the total meridional distance of the map. It may be advisable in some localities, or for special reasons, to bring them closer together in order to have greater accuracy in the center of the map at the expense of the upper and lower border areas.
In general, for equal distribution of scale error, the standard parallels are placed within the area represented at distances from its northern and southern limits each equal to one-sixth of the total meridional distance of the map. It may be advisable in some localities, or for special reasons, to bring them closer together in order to have greater accuracy in the center of the map at the expense of the upper and lower border areas.
I also must admit the math level of 'Savric B, Jenny B. 2016. Automating the selection of standard parallels for conic map projections: Computers and Geosciences, 90, 202–212.' is beyond my current knowledge. I would've loved to post the result to the distortion measure ( 204 Eq(2) ) of the chart though.