Ground School Exam Questions & Question Banks
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Uuuhh??? 
Correct me if I'm wrong, but applying wind to TAS gives you ground speed, not a different IAS. I can't see that your Avcom man's reasoning is correct - but then again, I might be wrong. Rainboe's reasoning makes more sense.
Using your Aristo, you can see that at that height, and temp with 100 IAS, your TAS should be 113kts (as shown by your Avcom man). However, your real TAS is 120kts (109kts out and 130kts back with 11kts wind component). Therefor, using your Aristo, 120Kts TAS equates to a CAS of 105Kts. This gives you a 5kt under read. That would be my reasoning, but it seems as though my answer is incorrect.
CHEERS!!!
I
Correct me if I'm wrong, but applying wind to TAS gives you ground speed, not a different IAS. I can't see that your Avcom man's reasoning is correct - but then again, I might be wrong. Rainboe's reasoning makes more sense. Using your Aristo, you can see that at that height, and temp with 100 IAS, your TAS should be 113kts (as shown by your Avcom man). However, your real TAS is 120kts (109kts out and 130kts back with 11kts wind component). Therefor, using your Aristo, 120Kts TAS equates to a CAS of 105Kts. This gives you a 5kt under read. That would be my reasoning, but it seems as though my answer is incorrect.
CHEERS!!!
I
Last edited by Ibanez; 14th Aug 2005 at 14:10.
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zssp, Sean,
If indeed you did fail instruments because of this question, then you have a good case to protest - none of the answers are correct.
Please forgive the degree of decimal places, included so that this can be proven conclusively.
The basic mathematics indicate that the said time intervals may only be achieved at a TAS of 119.293656 Kt, and a Wind Component of -10.20274691 Kt on the first leg, and conversly +10.20274691 Kt on the second, i.e. a Groundspeed outbound of 109.0909091 Kt, and 129.4964029 on return. Apply these Ground Speeds to the 5 nm between pylons without ANY rounding off of the results -
5 nm at G/S 109.0909091 = 2:45 EXACTLY
5 nm at G/S 129.4964029 = 2:19 EXACTLY
OK, a TAS of 119.293656 Kt is proven. At 7000 feet Pressure Height and a Static Air Temperature of +15°C. To achieve the quoted TAS in these conditions requires EAS 104.79, Mach No. 0.1803, or, importantly for you, a CAS of 104.8868949.
Thus, if the flight is conducted at 100 KIAS, the ASI is UNDER-READING by 4.8868949 Kt, 5 Kt between friends.
NONE of the answers are correct. Protest the result Sean, protest!
Regards,
Old Smokey
If indeed you did fail instruments because of this question, then you have a good case to protest - none of the answers are correct.
Please forgive the degree of decimal places, included so that this can be proven conclusively.
The basic mathematics indicate that the said time intervals may only be achieved at a TAS of 119.293656 Kt, and a Wind Component of -10.20274691 Kt on the first leg, and conversly +10.20274691 Kt on the second, i.e. a Groundspeed outbound of 109.0909091 Kt, and 129.4964029 on return. Apply these Ground Speeds to the 5 nm between pylons without ANY rounding off of the results -
5 nm at G/S 109.0909091 = 2:45 EXACTLY
5 nm at G/S 129.4964029 = 2:19 EXACTLY
OK, a TAS of 119.293656 Kt is proven. At 7000 feet Pressure Height and a Static Air Temperature of +15°C. To achieve the quoted TAS in these conditions requires EAS 104.79, Mach No. 0.1803, or, importantly for you, a CAS of 104.8868949.
Thus, if the flight is conducted at 100 KIAS, the ASI is UNDER-READING by 4.8868949 Kt, 5 Kt between friends.
NONE of the answers are correct. Protest the result Sean, protest!
Regards,
Old Smokey
Better red than ...
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Or you could do it my way... If in doubt, guess 'C'!!
h-r
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zssp , Congratulations on your pass.
Cron, unfortunately it cannot be done that way, because as a percentage penalty or gain, the same Wind Component has a greater effect upon time as a Headwind than when a Tailwind. Thus, the solution can not be found by taking the total distance against the total time, the TAS will always come out on the low side.
Consider a 100 Kt TAS over a 100 mile course. In nil wind, it comes out at 60 minutes both directions, so far so good, but now insert a 20 Kt Headwind outbound, which becomes 20 Kt Tailwind for the reverse direction –
100 nm at G/S 80 Kt = 75 minutes (EXACTLY)
100 nm at G/S 120 Kt = 50 minutes (EXACTLY)
Now, if we use your technique of total distance against total time, that’s –
200 nm in 125 minutes = 96 Knots – Wrong, we knew in advance that the TAS = 100 Kt.
Now, if instead we calculated the G/S in both directions, and found the mean, we would have the answer –
100 nm in 75 minutes = G/S 80
100 nm in 50 minutes = G/S 120
Mean G/S = (80 + 120) / 2 = 100 Kts – Correct!
(All of the above assumes of course, that there was no drift, because any drift will effectively increase the Headwind and decrease the Tailwind).
It’s because of this type of reasoning that we need to use a more complex formula in calculating PNRs, than simply taking half of the useable endurance to be used on the outward leg.
Regards,
Old Smokey
Cron, unfortunately it cannot be done that way, because as a percentage penalty or gain, the same Wind Component has a greater effect upon time as a Headwind than when a Tailwind. Thus, the solution can not be found by taking the total distance against the total time, the TAS will always come out on the low side.
Consider a 100 Kt TAS over a 100 mile course. In nil wind, it comes out at 60 minutes both directions, so far so good, but now insert a 20 Kt Headwind outbound, which becomes 20 Kt Tailwind for the reverse direction –
100 nm at G/S 80 Kt = 75 minutes (EXACTLY)
100 nm at G/S 120 Kt = 50 minutes (EXACTLY)
Now, if we use your technique of total distance against total time, that’s –
200 nm in 125 minutes = 96 Knots – Wrong, we knew in advance that the TAS = 100 Kt.
Now, if instead we calculated the G/S in both directions, and found the mean, we would have the answer –
100 nm in 75 minutes = G/S 80
100 nm in 50 minutes = G/S 120
Mean G/S = (80 + 120) / 2 = 100 Kts – Correct!
(All of the above assumes of course, that there was no drift, because any drift will effectively increase the Headwind and decrease the Tailwind).
It’s because of this type of reasoning that we need to use a more complex formula in calculating PNRs, than simply taking half of the useable endurance to be used on the outward leg.
Regards,
Old Smokey
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something wrong here
Friends
This is a simple question. 109kts against the wind, 129 knots with the wind therefore 119ktas still air. Drift is not relevant because the reverse is flown not the reciprocal i.e. the paper pilot flies back to the start point. I can't quite see why we need to know Mach No but under ISA conditions at 7000ft the temp should be 1 deg C but we are told "today" it is 15 deg C. That makes local speed of sound 1118.64ft/sec so M0.18 it is. Now using an electronic calculator rather than the whirly wheel I obtain CAS of 105kts. Thus agreeing with old Smokey. So the IAS under-reads by 5kts. So either a) the examiner got it wrong or b) we are supposed to second guess what the examiner wants or c) we have not been given the question in full. If on the other hand we had to give evidence of our working some credit could be gained and the exam would be a continuation of the learning process.
This is a simple question. 109kts against the wind, 129 knots with the wind therefore 119ktas still air. Drift is not relevant because the reverse is flown not the reciprocal i.e. the paper pilot flies back to the start point. I can't quite see why we need to know Mach No but under ISA conditions at 7000ft the temp should be 1 deg C but we are told "today" it is 15 deg C. That makes local speed of sound 1118.64ft/sec so M0.18 it is. Now using an electronic calculator rather than the whirly wheel I obtain CAS of 105kts. Thus agreeing with old Smokey. So the IAS under-reads by 5kts. So either a) the examiner got it wrong or b) we are supposed to second guess what the examiner wants or c) we have not been given the question in full. If on the other hand we had to give evidence of our working some credit could be gained and the exam would be a continuation of the learning process.
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try this
Dear Sirs
I refer you to the recent exam paper in which students are expected to deduce an IAS error. From the data given that an aircraft is at 7000ft pressure altitude, an air temperature of 15 deg C and accomplishes 5 nautical mile outbound and inbound legs in 2min 45secs and 2min 19secs respectively it can be deduced that true airspeed is 119 knots. If the IAS calibration is correct it should therefore read 105knots but it reads 100kts instead. This is under-reading by 5 knots but no such option is given in the multiple-choice selection. Even if the erroneous assumption is made that true airspeed is total distance divided by total time (it is of course deduced from outbound and inbound speeds calculated separately) it is not possible to mistakenly select a value from the range offered. As the aircraft is supposed to reverse its route and not fly a reciprocal bearing (which in wind would not take it back to its starting point) drift is not an issue. I am therefore at a loss as to how the examiner who drafted the question expects it to be answered. I await your reply with interest.
I refer you to the recent exam paper in which students are expected to deduce an IAS error. From the data given that an aircraft is at 7000ft pressure altitude, an air temperature of 15 deg C and accomplishes 5 nautical mile outbound and inbound legs in 2min 45secs and 2min 19secs respectively it can be deduced that true airspeed is 119 knots. If the IAS calibration is correct it should therefore read 105knots but it reads 100kts instead. This is under-reading by 5 knots but no such option is given in the multiple-choice selection. Even if the erroneous assumption is made that true airspeed is total distance divided by total time (it is of course deduced from outbound and inbound speeds calculated separately) it is not possible to mistakenly select a value from the range offered. As the aircraft is supposed to reverse its route and not fly a reciprocal bearing (which in wind would not take it back to its starting point) drift is not an issue. I am therefore at a loss as to how the examiner who drafted the question expects it to be answered. I await your reply with interest.
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Question about pressure
Can anyone help me to differenciate between the following?
Absolute Pressure
Gauge Pressure
Now I think they are related by:
Absolute Pressure = Gauge Pressure + Atmospheric Pressure
So at 30,000ft the pressure is 300mb...which pressure are we talking about??
Cheers
smithgd
Absolute Pressure
Gauge Pressure
Now I think they are related by:
Absolute Pressure = Gauge Pressure + Atmospheric Pressure
So at 30,000ft the pressure is 300mb...which pressure are we talking about??
Cheers
smithgd
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I think that the "bottom line" here lies not so much in nit-picking over 2 knots difference between the correct answer and the "nearest correct answer". 2 knots variation is definately within the "green band" for practical day to day operations.
In sitting for exams, the candidate will typically do his / her working to the highest degree of precision possible, and considerable stress can be caused in an exam situation where the correct answer fits none of the answer choices available.
BTW, drift WILL complicate the issue!
Regards,
Old Smokey
In sitting for exams, the candidate will typically do his / her working to the highest degree of precision possible, and considerable stress can be caused in an exam situation where the correct answer fits none of the answer choices available.
BTW, drift WILL complicate the issue!
Regards,
Old Smokey
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ON-Line JAA Question Banks for ATPL(A)
Dear Pprune,
I am writing for the first time and I would like to get some opinions on the following query.
Which On-Line JAA Question Bank is best to prepare someone for the ATPL(A) Exams?
I am aware of two Question Banks.
The one belongs to a company named Aerosolutions and the other is the Bristol Ground School.
Thank you very much,
Geoge KOUMIS
I am writing for the first time and I would like to get some opinions on the following query.
Which On-Line JAA Question Bank is best to prepare someone for the ATPL(A) Exams?
I am aware of two Question Banks.
The one belongs to a company named Aerosolutions and the other is the Bristol Ground School.
Thank you very much,
Geoge KOUMIS