Quadrantal Rule
Transition Level is defined by ICAO in PANS-ATM as:
Transition level. The lowest flight level available for use above the transition altitude.
Unfortunately "available for use" is subject to interpretation. Different states use different conventions. In the UK, if you're a VFR flight with a QNh of 1012, FL31 is "available for use". If you're an IFR flight, different levels are the lowest "available for use" depending on direction, though most (including MATS Pt 1) would interpret transition level as the lowest multiple of 5 i.e. FL35 in those circumstances. Other states make it the lowest multiple of 10 above the transition altitude, because only those levels are used for IFR, and still others make it lowest multiple of 10 at least 1000 ft above the transition altitude. Again according to ICAO, the transition level must be above the minimum IFR fight altitude for a control area.
As such, transition level doesn't have much use to pilots. The transition altitude is the phrase used in Rule 34, and neither is used in level selection rules in ICAO Annex 2.
Transition level. The lowest flight level available for use above the transition altitude.
Unfortunately "available for use" is subject to interpretation. Different states use different conventions. In the UK, if you're a VFR flight with a QNh of 1012, FL31 is "available for use". If you're an IFR flight, different levels are the lowest "available for use" depending on direction, though most (including MATS Pt 1) would interpret transition level as the lowest multiple of 5 i.e. FL35 in those circumstances. Other states make it the lowest multiple of 10 above the transition altitude, because only those levels are used for IFR, and still others make it lowest multiple of 10 at least 1000 ft above the transition altitude. Again according to ICAO, the transition level must be above the minimum IFR fight altitude for a control area.
As such, transition level doesn't have much use to pilots. The transition altitude is the phrase used in Rule 34, and neither is used in level selection rules in ICAO Annex 2.
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Quote:
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?
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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!
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?
---------------
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!
OK - I understand that the transition altitude is 3000ft amsl - but if the transition altitude is 3000ft AMSL why is the transition level FL35 and the answer FL50? It needs explaining in basic terms! I'm probably just not seeing something I should be and haven't got access to my books at the moment!
Last edited by samuelwmartin; 16th Jan 2008 at 09:51.
Mind you that said you have to question how effective the Quadrantal rule is which I believe is only notified for the UK.
There was a theory that if you let aircraft fly around at random levels there would be less risk of collision! (Bear in mind that the Quadrantal Rule is for use outside controlled airspace).
Other States seem to manage quite well with the SemiCircular Rule!
There was a theory that if you let aircraft fly around at random levels there would be less risk of collision! (Bear in mind that the Quadrantal Rule is for use outside controlled airspace).
Other States seem to manage quite well with the SemiCircular Rule!
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Islander2
I completely understand that the actual depth of the layer will vary on the QNH. I simply had it in my head that there was an absolute minimum of FL40. It may be that this is a figure I have heard abroad.
Personally, I would question the wisdom switching to levels for cruising at 3000ft in a country where the spot heights extend to over 4400ft. If the pressure drops you could find yourself rather closer to the ground than you were expecting. It is much easier to reset the QNH periodically than constantly trying to calculate your actual altitude whenever there is a change in the QNH. It is fine if you're flying in places like East Anglia or the South East but I prefer to stay on the Regional QNH for VFR. Bear in mind that the higher levels are rarely an option around the higher ground in the U.K. if you want to remain VFR.
I completely understand that the actual depth of the layer will vary on the QNH. I simply had it in my head that there was an absolute minimum of FL40. It may be that this is a figure I have heard abroad.
Personally, I would question the wisdom switching to levels for cruising at 3000ft in a country where the spot heights extend to over 4400ft. If the pressure drops you could find yourself rather closer to the ground than you were expecting. It is much easier to reset the QNH periodically than constantly trying to calculate your actual altitude whenever there is a change in the QNH. It is fine if you're flying in places like East Anglia or the South East but I prefer to stay on the Regional QNH for VFR. Bear in mind that the higher levels are rarely an option around the higher ground in the U.K. if you want to remain VFR.
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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).
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Sam
Put the aircraft on the shelf at 3000ft with QNH 1010.
Now the aircraft is on a shelf it cannot climb or descend agreed.
Put you hand through the window and wind on 1013 (Pressure up = height/alt up).
Altimeter is now reading FLIGHT LEVEL(S) at approx FL3.1 so FL 30 IS NOT AVAILABLE--The next available FL is FL3.5 but on the mag track given in your question it would be FL50 (first quadrant = ODD)
OK - I understand that the transition altitude is 3000ft amsl - but if the transition altitude is 3000ft AMSL why is the transition level FL35 and the answer FL50? It needs explaining in basic terms! I'm probably just not seeing something I should be and haven't got access to my books at the moment!
Put the aircraft on the shelf at 3000ft with QNH 1010.
Now the aircraft is on a shelf it cannot climb or descend agreed.
Put you hand through the window and wind on 1013 (Pressure up = height/alt up).
Altimeter is now reading FLIGHT LEVEL(S) at approx FL3.1 so FL 30 IS NOT AVAILABLE--The next available FL is FL3.5 but on the mag track given in your question it would be FL50 (first quadrant = ODD)
Last edited by llanfairpg; 17th Jan 2008 at 12:04. Reason: hdg chaged to track--ref spitton
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In the case given no, but if the QNH was 1013 or HIGHER ,yes
or more simply you can fly at FL030 if the QNH is 1013 or higher( if trans alt is 3000 feet)
1. do you understand 'put the aircraft on the 3000ft shelf''?
2. do you understand--subscale up = alt up--subcale down = alt down?
as on pre flight instrument checks
or more simply you can fly at FL030 if the QNH is 1013 or higher( if trans alt is 3000 feet)
1. do you understand 'put the aircraft on the 3000ft shelf''?
2. do you understand--subscale up = alt up--subcale down = alt down?
as on pre flight instrument checks
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Dont worry most pilots forget it and it still ties many up in knots. In practice for pilots its not thought about to much on a day to day basis but you need to apply 'exam logic' to it. So put your a/c on the shelf and twiddle that altimeter!
Just to add to that Bob, the way I teach is is to to tell the student to imagine we have parked the aircraft on a shelf at 3000 feet. we open the window lean through and observe 3000 feet on the altimeter, we than set 1013, now what is the altimeter reading without any aircraft climb or descent? From their pre-flight altimeter checks they should at this stage know, pressure up = altitude up and vicky versa. I find taking the CLIMB element out and parking the aircraft simplifies understanding
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Bookworm,
FL31 will never come into it because it is not a flight level used in the table of crusing levels.
The 500ft vertical separation between levels is universal. The only difference being that the UK has a "quadrantal" use for it while other places reserve the intermediate 500ft levels for VFR flights and the whole thousands for IFR flights.
In accordance with ICAO altimeter setting procedures which every PPL should have been taught as it is part of the JAR-FCL sylabus, the transition level is defined as the lowest flight level available for use above the transition altitude.
ICAO leaves two options for countries when choosing this level. Countries can require vertical separation between an aircraft at the transition level and the transition altitude and thus the transition layer will be a minimum of 1000ft. With this system you can indeed have a transition level of FL45 (i.e. an intermediate 500ft) however, in such a situation, ATC will often use a whole FL as the minimum crusing or holding level. Otherwise with the requirement to provide 1000ft vertical between IFR flights, the 500ft gets pushed up and up the stack and the posibility of an error.
The other option wjich the UK uses is to not provide any vertical separation between the TL and the TA and simply require the TL to be above the TA. The UK then uses minimum stack levels or minimum cruise levels to provide vertical separation when required.
Overall as I said previously, the TL is meaningless for most pilots. If you are climbing to a flight level then you set the altimeter to standard setting when cleared so that you do not forget and when cleared to descend to an altitude you set the QNH again so that you do not forget. The exceptions being when asked to report passsing an altitude in the climb or flight level in the descent.
Whoever has a problem with a 3000ft transition altitude when the higest obstacle is over 4000ft needs to remember the following;
1. There is a UK AIC with a Terrain Clearance table that you can print off.
2. You also have to factor in wind effects and temperature corrections as appropriate thus even using the QNH for minimum safe vertivcal separation from such an obstacle is not simply a case to making the altimeter set to an appropriate QNH read more than the altitude of the obstacle!
There is a graph in the UK AIP that you can enter with the QNH and altitude you want to fly at to find the minimum flight level that satisfies that requirement. You can use it to find the level that is 500ft above the transition altitude or to find the level that is 2000ft above your local Munroe.
I recomend that all IFR fliers in the UK have the terrain clearance table from the AIC avaiable in flight.
Regards,
DFC
FL31 will never come into it because it is not a flight level used in the table of crusing levels.
The 500ft vertical separation between levels is universal. The only difference being that the UK has a "quadrantal" use for it while other places reserve the intermediate 500ft levels for VFR flights and the whole thousands for IFR flights.
In accordance with ICAO altimeter setting procedures which every PPL should have been taught as it is part of the JAR-FCL sylabus, the transition level is defined as the lowest flight level available for use above the transition altitude.
ICAO leaves two options for countries when choosing this level. Countries can require vertical separation between an aircraft at the transition level and the transition altitude and thus the transition layer will be a minimum of 1000ft. With this system you can indeed have a transition level of FL45 (i.e. an intermediate 500ft) however, in such a situation, ATC will often use a whole FL as the minimum crusing or holding level. Otherwise with the requirement to provide 1000ft vertical between IFR flights, the 500ft gets pushed up and up the stack and the posibility of an error.
The other option wjich the UK uses is to not provide any vertical separation between the TL and the TA and simply require the TL to be above the TA. The UK then uses minimum stack levels or minimum cruise levels to provide vertical separation when required.
Overall as I said previously, the TL is meaningless for most pilots. If you are climbing to a flight level then you set the altimeter to standard setting when cleared so that you do not forget and when cleared to descend to an altitude you set the QNH again so that you do not forget. The exceptions being when asked to report passsing an altitude in the climb or flight level in the descent.
Whoever has a problem with a 3000ft transition altitude when the higest obstacle is over 4000ft needs to remember the following;
1. There is a UK AIC with a Terrain Clearance table that you can print off.
2. You also have to factor in wind effects and temperature corrections as appropriate thus even using the QNH for minimum safe vertivcal separation from such an obstacle is not simply a case to making the altimeter set to an appropriate QNH read more than the altitude of the obstacle!
There is a graph in the UK AIP that you can enter with the QNH and altitude you want to fly at to find the minimum flight level that satisfies that requirement. You can use it to find the level that is 500ft above the transition altitude or to find the level that is 2000ft above your local Munroe.
I recomend that all IFR fliers in the UK have the terrain clearance table from the AIC avaiable in flight.
Regards,
DFC
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DFC
A good post and I think you've summarised this debate perfectly. The only thing I would add is that when I mentioned the terrain issue, I was thinking of VFR and that going up 2000ft to the next FL for your track in a situation of falling pressure in order to maintain terrain clearance is frequently not possible.
A good post and I think you've summarised this debate perfectly. The only thing I would add is that when I mentioned the terrain issue, I was thinking of VFR and that going up 2000ft to the next FL for your track in a situation of falling pressure in order to maintain terrain clearance is frequently not possible.
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Altimeter is now reading FLIGHT LEVEL(S) at approx FL3.1 so FL 30 IS NOT AVAILABLE--The next available FL is FL3.5 but on the mag heading given in your question it would be FL50 (first quadrant = ODD)
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I was thinking of VFR and that going up 2000ft to the next FL for your track in a situation of falling pressure in order to maintain terrain clearance is frequently not possible.
The UK only recomends that VFR flights follow the quadrantal and it is very good advice.
In other countries where VFR flights cruise according to the ICAO semicircular table of flight levels for VFR flights then one will often find that such a requrement only applies when more than a specified height above the terrain. 3000ft in some cases or in others "3000ft AMSL or 1000ft AGL whichever is the higher".
The ENR section of the appropriate AIP is the best place to start looking.
Regards,
DFC
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Only if the guy coming the other way is like minded!
Semicircular and Quadrantal rules do not provide any form of separation. They are simply the start in the creation of an orderly system rather than a safe system.
Regards,
DFC
ICAO leaves two options for countries when choosing this level. Countries can require vertical separation between an aircraft at the transition level and the transition altitude and thus the transition layer will be a minimum of 1000ft. With this system you can indeed have a transition level of FL45 (i.e. an intermediate 500ft) however, in such a situation, ATC will often use a whole FL as the minimum crusing or holding level.
METAR EDSB 162020Z 21008KT 8000 -RA SCT038 BKN044 08/04 Q1005=
The transition level is clearly stated on the ATIS as "FL70". If multiples of 500 ft were used, the transition level would be FL65, as this provides 1000 ft separation from 5000 ft.
I have never in 15 years of flying in Germany (or anywhere else I recall hearing the TL on ATIS) heard a transition level of anything other than a multiple of 1000 ft.
Since we're agreed that TL is essentially meaningless, it's of academic interest.
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Bookworm,
In the case of Germany you are correct - For IFR flights the altitude at and below which the pilot shall set the altimeter to the QNH value transmitted by the competent ATC unit and above which he shall use the standard altimeter setting is established at 5000 ft MSL (transition altitude). For flights above the transition altitude, an altitude is established which, taking into account the valid QNH value, corresponds to the flight level for IFR, at least 1000 ft above the transition altitude (transition level).
Thus in Germany the transition level is always an IFR level. That is not the case everywhere.
Every country is different.
For example in Poland - the trasnition altitude is 6500ft AMSL and the transition Level is FL80 unless the QNH is 995 or less when it is FL90.
ENR 1.7 of the AIP for whatever country you want to fly in will let you know what the requirements are.
Regards,
DFC
In the case of Germany you are correct - For IFR flights the altitude at and below which the pilot shall set the altimeter to the QNH value transmitted by the competent ATC unit and above which he shall use the standard altimeter setting is established at 5000 ft MSL (transition altitude). For flights above the transition altitude, an altitude is established which, taking into account the valid QNH value, corresponds to the flight level for IFR, at least 1000 ft above the transition altitude (transition level).
Thus in Germany the transition level is always an IFR level. That is not the case everywhere.
Every country is different.
For example in Poland - the trasnition altitude is 6500ft AMSL and the transition Level is FL80 unless the QNH is 995 or less when it is FL90.
ENR 1.7 of the AIP for whatever country you want to fly in will let you know what the requirements are.
Regards,
DFC