Quadrantal Rule
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Quadrantal Rule
Can u fly at the transition altitude. Ie fl30 when using quadrantal rule?
I was told no but think u can?
Also, why is the answer to this question FL50? And not FL30?
An aircraft is flying on a magnetic track of 075 degrees. The QNH is 1010. What is the lowest available flight level to fly in accordance with the quadrantsl rule?
thanks!
I was told no but think u can?
Also, why is the answer to this question FL50? And not FL30?
An aircraft is flying on a magnetic track of 075 degrees. The QNH is 1010. What is the lowest available flight level to fly in accordance with the quadrantsl rule?
thanks!
The transition altitude is an altitude (based on QNH) but the transition level is a Flight Level (based on 1013.25 mb).
Yes you can fly at the Transition Level whilst complying with the Quadrantal Rule. (Equally you can flt at the Transition Altitude but this would not be in accordance with the Quadrantal Rule because the latter is based on 1013.25 and magnetic track).
Assuming the Transition Altitude in this case is 3,000 ft amsl then the Transition Level would be FL 35. Since we are in the first quadrant an ODD flight level is appropriate so in this case Flight Level 50 would be appropriate.
Hope this helps!
Yes you can fly at the Transition Level whilst complying with the Quadrantal Rule. (Equally you can flt at the Transition Altitude but this would not be in accordance with the Quadrantal Rule because the latter is based on 1013.25 and magnetic track).
An aircraft is flying on a magnetic track of 075 degrees. The QNH is 1010. What is the lowest available flight level to fly in accordance with the quadrantsl rule?
Hope this helps!
An aircraft is flying on a magnetic track of 075 degrees. The QNH is 1010. What is the lowest available flight level to fly in accordance with the quadrantal rule?
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The tranistion altitude is not always 3000ft although is most commonly used. So if we take 3000 ft as the tranistion altitude then FL30 is the lowest possible FL.
OK....FL are based on 1013mb.
A heading of 075 is an odd heading so levels that we can fly are FL30, FL50, FL70 etc.
Now lets take your QNH of 1010mb Thisis 3mb lower than the 1013mb. lets remember that 1mb=30ft (actualy 27ft to be accurate). So 3mb multiplied by 30ft = 90ft.
3000ft - 90ft = 2010ft Therefore FL30 is not available so you would need to fly the next available FL for you altitude whcih is FL50.
Does that help?
OK....FL are based on 1013mb.
A heading of 075 is an odd heading so levels that we can fly are FL30, FL50, FL70 etc.
Now lets take your QNH of 1010mb Thisis 3mb lower than the 1013mb. lets remember that 1mb=30ft (actualy 27ft to be accurate). So 3mb multiplied by 30ft = 90ft.
3000ft - 90ft = 2010ft Therefore FL30 is not available so you would need to fly the next available FL for you altitude whcih is FL50.
Does that help?
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You can cruise at the transition altitude if you want. The quadrantal or semicircular rules only apply above the transition altitude.
The transition level in the UK is the first flight level above the transition altitude.
Note that while the transition level is above the transition altitude it is not separated from it i.e. the transition level may be 1ft above the transition altitude.
If the QNH is 1013.2 then the flight levels will co-incide with altitudes i.e. an aircraft cruising at FL30 will be 3000ft AMSL.
In this case since FL30 is not above the transition altitude then of course the transition level will be FL35 and you can see that by chance an aircraft at FL35 will be 500ft above an aircraft at 3000ft QNH.
As the pressure reduces below 1013.2, the flight levels move closer to the surface. Thus you can see that with reducing pressure FL35 will get closer to 3000 AMSL and eventually be under 3000ft AMSL.
Similarly, as pressure increases above 1013.2 the flight levels move up. Thus with a QNH of 1014, FL30 is actually 24ft above 3000ft AMSL and is therefore the transition level.
You can in this case cruise at FL30 in the appropriate direction however you need to be aware that while you will have 500ft separaton from the closest traffic above cruising at FL35, you will only have 24ft separation from traffic cruising at the transition altitude.
If the pressure increases enough, FL25 and then FL20 will eventually be above 3000ft AMSL and thus they will in turn become the transition level. Get your calculator out to work out when
Since the quadrantal rule applies to flight above 3000ft AMSL (or the transition altitude if higher), you can never fly at a flight level that causes you to be below the transition altitude.
Thus in the example given, FL50 is the first available level for that direction which is above the transition altitude.
Note that in other countries, the transition level may be the lowest flight level that provides a minimum of 1000ft separation from the transition altitude.
From a practical point of view you will not care much about the transition level, you will be more interested in a flight level that provides a minimum of 500ft separation from the transition altitude.
Regards,
DFC
The transition level in the UK is the first flight level above the transition altitude.
Note that while the transition level is above the transition altitude it is not separated from it i.e. the transition level may be 1ft above the transition altitude.
If the QNH is 1013.2 then the flight levels will co-incide with altitudes i.e. an aircraft cruising at FL30 will be 3000ft AMSL.
In this case since FL30 is not above the transition altitude then of course the transition level will be FL35 and you can see that by chance an aircraft at FL35 will be 500ft above an aircraft at 3000ft QNH.
As the pressure reduces below 1013.2, the flight levels move closer to the surface. Thus you can see that with reducing pressure FL35 will get closer to 3000 AMSL and eventually be under 3000ft AMSL.
Similarly, as pressure increases above 1013.2 the flight levels move up. Thus with a QNH of 1014, FL30 is actually 24ft above 3000ft AMSL and is therefore the transition level.
You can in this case cruise at FL30 in the appropriate direction however you need to be aware that while you will have 500ft separaton from the closest traffic above cruising at FL35, you will only have 24ft separation from traffic cruising at the transition altitude.
If the pressure increases enough, FL25 and then FL20 will eventually be above 3000ft AMSL and thus they will in turn become the transition level. Get your calculator out to work out when
Since the quadrantal rule applies to flight above 3000ft AMSL (or the transition altitude if higher), you can never fly at a flight level that causes you to be below the transition altitude.
Thus in the example given, FL50 is the first available level for that direction which is above the transition altitude.
Note that in other countries, the transition level may be the lowest flight level that provides a minimum of 1000ft separation from the transition altitude.
From a practical point of view you will not care much about the transition level, you will be more interested in a flight level that provides a minimum of 500ft separation from the transition altitude.
Regards,
DFC
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The lowest usable flight level is the transition level of FL40.
1013.2 - 1010 = 3.2 Mb
3.2 * 30 = 96ft
The position of FL30 is 96ft below (pressure is lower) 3000ft AMSL.
Therefore, FL35 is sitting at 3404ft AMSL and is thus 404ft above the transition altitude.
Thus FL35 is the transition level and is the lowest useable flight level.
However, remember that cruising at FL35 will only provide 404ft vertical separation from flights cruising at 3000ft QNH.
Regards,
DFC
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The question was not on the lowest useable FL. It was for the lowest available FL for a heading of 075 with a QNH of 1010
FL35 is the lowest useable FL based on QNH 1010.
FL35 is the lowest useable FL based on QNH 1010.
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Yes.
That is why if you read my first post you will see;
The second post was a response to the one above it which is an erroneous statement.
Regards,
DFC
That is why if you read my first post you will see;
Thus in the example given, FL50 is the first available level for that direction which is above the transition altitude.
Regards,
DFC
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DFC
All I was saying is that FL40 is the lowest cruising level. I'm well aware that it is not valid on 075(M). FL35 is NOT valid as a cruising level. 3000ft amsl is the point at which you reset the altimeter, i.e. transition altitude, but the transition level in the U.K. is FL40 with the gap in between being the transition layer. This exists purely to give separation based on variations between the QNH and the QNE. You normally reset the QNH when it is passed by ATC when IFR or passing FL40 if VFR and flying levels.
All I was saying is that FL40 is the lowest cruising level. I'm well aware that it is not valid on 075(M). FL35 is NOT valid as a cruising level. 3000ft amsl is the point at which you reset the altimeter, i.e. transition altitude, but the transition level in the U.K. is FL40 with the gap in between being the transition layer. This exists purely to give separation based on variations between the QNH and the QNE. You normally reset the QNH when it is passed by ATC when IFR or passing FL40 if VFR and flying levels.
Last edited by pilotincommand; 15th Jan 2008 at 20:44.
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Islander2
I've had a quick look through the AIP but I can't see anything that contradicts what I said previously. If anyone knows better, or if I've missed something in the AIP, I will happily stand corrected but, to the best of my knowledge, FL40 is the nominal transition level in this country. Most plates say that transition level is as given by ATC but that is for IFR and is what I meant when I said you normally reset the QNH when it is passed to you.
I've had a quick look through the AIP but I can't see anything that contradicts what I said previously. If anyone knows better, or if I've missed something in the AIP, I will happily stand corrected but, to the best of my knowledge, FL40 is the nominal transition level in this country. Most plates say that transition level is as given by ATC but that is for IFR and is what I meant when I said you normally reset the QNH when it is passed to you.
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As I've said before, there is a distinct possibility that I may be wrong about FL40. There was just something stuck in my head about that number.
What I am sure of is that the transition level is the lowest usable flight level and as such must be above the transition altitude, hence the transition layer. If you're IFR this is irrelevant as ATC will, in effect, tell you when to reset your altimeter by passing the QNH.
What I am sure of is that the transition level is the lowest usable flight level and as such must be above the transition altitude, hence the transition layer. If you're IFR this is irrelevant as ATC will, in effect, tell you when to reset your altimeter by passing the QNH.
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What I am sure of is that the transition level is the lowest usable flight level and as such must be above the transition altitude, hence the transition layer
However, in the example - Transition Altitude 3000ft QNH 1010, the lowest usable flight level in the UK according to the Quadrantal rule is FL35 and the transition layer is 404ft thick.
If the QNH was 1045 Milibars then FL25 would find itself some 3460ft AMSL and thus would be the transition level in the UK and would give a transition layer of 460ft.
As was said previously, the transition level varies depending on both the transition altitude and the QNH.
Regards,
DFC
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If the QNH was 1045 Milibars then FL25 would find itself some 3460ft AMSL and thus would be the transition level in the UK and would give a transition layer of 460ft.
DFC, I know you understand that, but pilotincommand is in serious need of some more bookwork before he adopts his nom de plume in anger.
I can't find the book definitions on the net at the moment but perhaps we need to remind ourselves that:-
Transition altitude is the altitude (in the "vicinity" of an aerodrome) at or below which the vertical position of the a/c will be expressed (to ATC) in terms of an altitude based on QNH.
Transition level is the Flight Level at or above which the vertical position of an a/c will be expressed in terms of a Flight Level (based on 1013.25 mb)
The bit between the Transition Altitude and the Transition Level is the Transition Layer. When flying in the Transition Layer the vertical position of the aircraft is expressed in terms of a Flight Level when climbing or an Altitude when descending.
The way I teach the computation of the Transition Level is to imagine you climb (with QNH set) and level off at the Transition Altitude (although fixed for a particular aerodrome it does vary across the UK - eg 3,000 ft for aerodromes outside controlled airspace, 4000 ft at EMA/BHX.....etc as published). Whilst flying level you then set 1013.25 mb. If you wind on the pressure the altimeter indication will increase, if you wind off the pressure it will decrease (by approx 30 ft per mb). Lets say the altimeter now reads 3,400 - the TL will then be FL 35 (ie the next 500 ft level above your current "level"). Alternatively lets say the altimeter now reads 2,300 - the TL would then be FL 25.
I hope this helps.
Transition altitude is the altitude (in the "vicinity" of an aerodrome) at or below which the vertical position of the a/c will be expressed (to ATC) in terms of an altitude based on QNH.
Transition level is the Flight Level at or above which the vertical position of an a/c will be expressed in terms of a Flight Level (based on 1013.25 mb)
The bit between the Transition Altitude and the Transition Level is the Transition Layer. When flying in the Transition Layer the vertical position of the aircraft is expressed in terms of a Flight Level when climbing or an Altitude when descending.
The way I teach the computation of the Transition Level is to imagine you climb (with QNH set) and level off at the Transition Altitude (although fixed for a particular aerodrome it does vary across the UK - eg 3,000 ft for aerodromes outside controlled airspace, 4000 ft at EMA/BHX.....etc as published). Whilst flying level you then set 1013.25 mb. If you wind on the pressure the altimeter indication will increase, if you wind off the pressure it will decrease (by approx 30 ft per mb). Lets say the altimeter now reads 3,400 - the TL will then be FL 35 (ie the next 500 ft level above your current "level"). Alternatively lets say the altimeter now reads 2,300 - the TL would then be FL 25.
I hope this helps.