Ground School Exam Questions & Question Banks
Join Date: Jun 2002
Location: London
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
It is to do with direction of Low Press wind direction which moving anti clockwise
So, imagine you are flying from east to west from the centre of a low through to the centre of the high. As you are going away from the centre of the low, the winds will rotate anticlockwise (as you’re in the northern hemisphere), hence you will be experiencing a crosswind from the North. As you approach the high, the winds will be rotating clockwise (as you are in the northern hems), so the first effect you will get is again a northerly crosswind. All the time your true altitude will be increasing.
If you continue to fly through the high to the other side of it, you will eventually start experiencing a crosswind from the south and your true altitude will start decreasing!
It’s much easier to understand if you draw a diagram resembling what I said above.
You can use the Ballots law but I didn’t bother with it.
Good luck
Join Date: Sep 2004
Location: Essex, UK
Posts: 240
Likes: 0
Received 0 Likes
on
0 Posts
I agree with Dotun, I thought in a real world its meant to be 40-60% but in a pressurised aircraft its only 5-10% hence cabin crew rehydrating passengers with drinks all the time....
'all the time' well depends which airline your on I guess lol...
'all the time' well depends which airline your on I guess lol...
Join Date: Sep 2004
Location: Essex, UK
Posts: 240
Likes: 0
Received 0 Likes
on
0 Posts
I thought Bristol gs online was quite accurate, although it does seem that the CAA are changing the wording and questions more and more...
Check your PM, Ive sent you my ID and password as Ive finished ATPL's now..and thats the sort of nice fella I am.
Check your PM, Ive sent you my ID and password as Ive finished ATPL's now..and thats the sort of nice fella I am.
Join Date: Oct 2000
Location: Bristol
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
At low level it would be correct to say that you would be flying into an area of surface high pressure, and baro error would be in the safe sense, altimiter underreading, height increasing.
This is a slightly deeper question, as it says you are flying on the 500hpa level, i.e. about 18,000ft. Up high you have to take into account temp error as well. You are flying on the 500hpa contour, and if the wind is from the right it means you are flying into an area where the contours are higher amsl, so your height is increasing. You do not know whether this is because surface pressure is increasing or because the air mass temp below you is increasing. Either or both could be the answer.
Dick W
This is a slightly deeper question, as it says you are flying on the 500hpa level, i.e. about 18,000ft. Up high you have to take into account temp error as well. You are flying on the 500hpa contour, and if the wind is from the right it means you are flying into an area where the contours are higher amsl, so your height is increasing. You do not know whether this is because surface pressure is increasing or because the air mass temp below you is increasing. Either or both could be the answer.
Dick W
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
if you could draw, and send to my email I think thatis only option will make easier for me to underdtand .
Also another q.
airlfield 200m above msl QNH 1009. The air temp is 10deg lower than standard. What is QFF
How do I get to correct answer of more than 1009
What is simplest way of differentiating QFF with QFE - or can one say that both are same
Also another q.
airlfield 200m above msl QNH 1009. The air temp is 10deg lower than standard. What is QFF
How do I get to correct answer of more than 1009
What is simplest way of differentiating QFF with QFE - or can one say that both are same
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
ATPL AFS question No of fire extinguishers 10 pax
How come in my feed back question s on fire extinguishers an AC with 10 max config
the correct ans for amount of fire extingishers to be equipped is
1 in cockpit
3 in cabin
IS it not between 7- 30 1exting uisher
please help v confusing
the correct ans for amount of fire extingishers to be equipped is
1 in cockpit
3 in cabin
IS it not between 7- 30 1exting uisher
please help v confusing
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
lol yes - do you know what i mean-- what kind of answer was that feedback giving out- must be a typo .. I mean 3 exting in 10 seater AC . I dont think so LOL Thanks for the reassurance. ZDefinately 1 then
7-30 ac
31 -60 2
61-200 3
201- 300 4
etc ....
601 or more 7
7-30 ac
31 -60 2
61-200 3
201- 300 4
etc ....
601 or more 7
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
ATPL Meteorology Question ISA
I found this question in Feedback
During a flight at FL135
true alt is 13500 Local QNH 1019
Air mass is colder than ISA ... how come- should it not be warmer than ISA if QNH is 1019 at FL135
During a flight at FL135
true alt is 13500 Local QNH 1019
Air mass is colder than ISA ... how come- should it not be warmer than ISA if QNH is 1019 at FL135
Join Date: Jun 2002
Location: Kilmacolm
Age: 47
Posts: 740
Likes: 0
Received 0 Likes
on
0 Posts
Hi A320',
As 1019 is higher than 1013, we shall need to add 27' * 6hPa = 162' onto 13,500 to give us our altitude above sea level. This gives us 13,662' above sea level.
However the question states that our "true" altitude is 13,500'.
As the true altitude is less than our altitude above sea level (true altitude of 13,500 as opposed to 13,662), the temperature must be colder than ISA.
Remember, if the column of air below you is colder than ISA then you are lower than the altitude above sea level. If the air is warmer than ISA then your true altitude will be higher than that indicated.
Best wishes,
Charlie Zulu.
As 1019 is higher than 1013, we shall need to add 27' * 6hPa = 162' onto 13,500 to give us our altitude above sea level. This gives us 13,662' above sea level.
However the question states that our "true" altitude is 13,500'.
As the true altitude is less than our altitude above sea level (true altitude of 13,500 as opposed to 13,662), the temperature must be colder than ISA.
Remember, if the column of air below you is colder than ISA then you are lower than the altitude above sea level. If the air is warmer than ISA then your true altitude will be higher than that indicated.
Best wishes,
Charlie Zulu.
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
thanks but a bit confused about the 1st paragraph of ur explanation.
Im ok with the rule high to low look out below - but is it not the higher you go the less hpA there is ?? so why do you say 1019 is higher than 1013 . 1019 would be lower in height but higher in hPa - so it would be less in height? Please help
Im ok with the rule high to low look out below - but is it not the higher you go the less hpA there is ?? so why do you say 1019 is higher than 1013 . 1019 would be lower in height but higher in hPa - so it would be less in height? Please help
Join Date: Oct 2000
Location: Bristol
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
Easy tiger! The question does not say it is 1019 at FL135. It says you are at FL135 and the local QNH is 1019. It also adds that air mass temp is less than ISA
QNH is a theoretical pressure at sea level, calculated as though ISA temps apply and so that your altimeter will read correctly at your datum height. In this case datum height is msl, but if QNH were given as an airfield QNH the datum height would be the airfield elvation.
So, point one. Your altimeter is measuring height from the 1013 pressure level when it should be measuring from the sea level 1019 pressure level, so you have a baro error to take out, as already explained
Point two. Even with the baro error corrected your altimeter will still be overreading if the air mass temp is below ISA, so there is a further error that brings your true height down to 13,500ft. Or, put it the other way, if you true height is down to 13,500ft the air must be colder.
The pressure at 13,500ish will be well below 1013 or 1019, more in the 600hpa region.
I have re-read this and recognise it as a long winded versio of what Charlie Zuylu has already said
Dick Whittingham
QNH is a theoretical pressure at sea level, calculated as though ISA temps apply and so that your altimeter will read correctly at your datum height. In this case datum height is msl, but if QNH were given as an airfield QNH the datum height would be the airfield elvation.
So, point one. Your altimeter is measuring height from the 1013 pressure level when it should be measuring from the sea level 1019 pressure level, so you have a baro error to take out, as already explained
Point two. Even with the baro error corrected your altimeter will still be overreading if the air mass temp is below ISA, so there is a further error that brings your true height down to 13,500ft. Or, put it the other way, if you true height is down to 13,500ft the air must be colder.
The pressure at 13,500ish will be well below 1013 or 1019, more in the 600hpa region.
I have re-read this and recognise it as a long winded versio of what Charlie Zuylu has already said
Dick Whittingham
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
ATPL MET Question True ALT/ temp
Flying FL 160
OAT +27c
sea level pres 1003(is this QNH?)
What is tru e Alt?
Must I 16000/27 to get 590
and - from 16000??
how come the ans is 15090 in the feedback
.. What am I doing wrong
OAT +27c
sea level pres 1003(is this QNH?)
What is tru e Alt?
Must I 16000/27 to get 590
and - from 16000??
how come the ans is 15090 in the feedback
.. What am I doing wrong
Join Date: Jan 2000
Location: UK
Posts: 955
Likes: 0
Received 0 Likes
on
0 Posts
Try this
.................well yes Global Warming indeed Number Cruncher !
many deaths at the surface that day due to 'pollution...'
--------------------------
Relationship of true and calibrated (indicated) altitude:
TA= CA + (CA-FE)*(ISADEV)/(273+OAT)
where
TA= True Altitude above sea-level
FE= Field Elevation of station providing the altimeter setting
CA= Calibrated altitude= Altitude indicated by altimeter when set to the
altimeter setting, corrected for calibration error.
ISADEV= Average deviation from standard temperature from standard in the air
column between the station and the aircraft (in C)
OAT= Outside air temperature (at altitude)
many deaths at the surface that day due to 'pollution...'
--------------------------
Relationship of true and calibrated (indicated) altitude:
TA= CA + (CA-FE)*(ISADEV)/(273+OAT)
where
TA= True Altitude above sea-level
FE= Field Elevation of station providing the altimeter setting
CA= Calibrated altitude= Altitude indicated by altimeter when set to the
altimeter setting, corrected for calibration error.
ISADEV= Average deviation from standard temperature from standard in the air
column between the station and the aircraft (in C)
OAT= Outside air temperature (at altitude)
Join Date: Aug 2005
Location: EEC
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
sorry its - 27c
RVR 800 --- thats is definition of all codes but not method for working out this type of question but thanks for your help
RVR I didnt read ur reply properly sorry ,, just realised ur method- ta will try
RVR - what if the question doesnt give me FE what do I do then........
RVR 800 --- thats is definition of all codes but not method for working out this type of question but thanks for your help
RVR I didnt read ur reply properly sorry ,, just realised ur method- ta will try
RVR - what if the question doesnt give me FE what do I do then........
Join Date: Jun 2002
Location: London
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
OK
The equation is as such:
16,000 - (16*4*-10) - ((1013-1003)*27) = 15,090
16,000 is the altitude
(16*4*-10) (16) is the flight level abbreviated to the first 1 or 2 digits. Multiply this by (4c). (4c for every 1,000ft). Multiply it by the ISA temp dev'n (-10), in this case at 16,000 the temp should be -10, but its -27.
Second part of the equation is 1013 as used for FL's, then adjust it for the actual QNH, 1003, and multiply it by the standard 27.
Use this formula for all these types of Q's.
Good luck
The equation is as such:
16,000 - (16*4*-10) - ((1013-1003)*27) = 15,090
16,000 is the altitude
(16*4*-10) (16) is the flight level abbreviated to the first 1 or 2 digits. Multiply this by (4c). (4c for every 1,000ft). Multiply it by the ISA temp dev'n (-10), in this case at 16,000 the temp should be -10, but its -27.
Second part of the equation is 1013 as used for FL's, then adjust it for the actual QNH, 1003, and multiply it by the standard 27.
Use this formula for all these types of Q's.
Good luck
Last edited by Number Cruncher; 12th Oct 2005 at 15:47.
Jet Blast Rat
Join Date: Jan 2001
Location: Sarfend-on-Sea
Age: 51
Posts: 2,081
Likes: 0
Received 0 Likes
on
0 Posts
Use yer CRP-5! It's a damned sight easier and a damned sight quicker than the formula, and that is what a CRP-5 is for. Easing your way and speeding you up. Having said that, even as a Nav instructor I find myself embarrassed for a CRP-5 at the moment, so cannot give you the exact figure it will get. If you want an explanation of how I am happy to oblige.
You need some attention to your brackets, Number Cruncher!
You need some attention to your brackets, Number Cruncher!