Changing altimeter setting
Thread Starter
Join Date: Jul 2001
Location: ITCZ
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Changing altimeter setting
I've recently changed employers and I think the guys here are messing with my head.
As long as I have been flying, I was taught that you should only change altimeter settings from QNH to 1013 and vise versa when either passing the transition altitude (going up) or transition level (going down).
The guys here say (with no specific procedure written down, mind you), you change the the altimeter setting when ATC clears you to a FL (going up) and an altitude (going down), well before crossing the transition layer. Their reasoning, it is more logical.
One guys logic is anothers insanity
Are the procedures different around the world?????
As long as I have been flying, I was taught that you should only change altimeter settings from QNH to 1013 and vise versa when either passing the transition altitude (going up) or transition level (going down).
The guys here say (with no specific procedure written down, mind you), you change the the altimeter setting when ATC clears you to a FL (going up) and an altitude (going down), well before crossing the transition layer. Their reasoning, it is more logical.
One guys logic is anothers insanity Are the procedures different around the world?????
Most European carriers change when cleared to a FL on the way up, and when cleared to an ALT on the way down.
At Ek we do it when at or close to transition.
Have done it both ways, and prefer to do it the European way...1 less thing to forget...
I think it really depends on your local transition level, Middle East is mostly around 15000, US is 18000 so it may make sense to change at transition. Personally not conviced as have seen it forgotten many times, if you change when cleared easy peasy..
At Ek we do it when at or close to transition.
Have done it both ways, and prefer to do it the European way...1 less thing to forget...
I think it really depends on your local transition level, Middle East is mostly around 15000, US is 18000 so it may make sense to change at transition. Personally not conviced as have seen it forgotten many times, if you change when cleared easy peasy..
We change to 1013 inly when passing Transition Altitude, but when cleared to an altitude (going down) we change to QNH as soon as we get the clearance to an altitude containing the latest QNH from ATC.
Small European carrier with some Lufthansa input.
Small European carrier with some Lufthansa input.
I totally agree with 145 qrh above. It is my understanding that when ATC clear you to a FL before transition then they assume that you are going to set 1013.25/29.92 and accept any inaccuracy in your read out.
Likewise, it is normal to set QNH right away when cleared down to an altitude. Do it when it is ordered and then you won't forget.
Likewise, it is normal to set QNH right away when cleared down to an altitude. Do it when it is ordered and then you won't forget.
Join Date: Mar 2006
Location: Choroni, sometimes
Posts: 1,974
Likes: 0
Received 0 Likes
on
0 Posts
Even if things are getting more complicated.
Our SOP are:
- PF sets Altimeter to cleared Value, e.g. cleared to an ALTITUDE - PF sets local QNH, cleared to a FL - PF sets Standard
- PNF remains on QNH when below TA, remains on Standard when above TL
regards
Our SOP are:
- PF sets Altimeter to cleared Value, e.g. cleared to an ALTITUDE - PF sets local QNH, cleared to a FL - PF sets Standard
- PNF remains on QNH when below TA, remains on Standard when above TL
regards
Warning Toxic!
Disgusted of Tunbridge
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
Likes: 0
Received 0 Likes
on
0 Posts
Smooze- wherever 'here' is, they are right. That is how you do it now. You do it that way as well because they are paying you, so you do it their way!
We change to standard on the way up at transition altitude, but on the way down we switch to QNH as soon as we get cleared to an altitude with a QNH. The standby altimeter however is set to QNH until TOC, then its set to standard, as soon as we get the ATIS of our destination its set to QNH again.
Transition Altitude is mostly around 5000ft at our usual destinations. Small european outfit, formerly owned and audited by BA.
Transition Altitude is mostly around 5000ft at our usual destinations. Small european outfit, formerly owned and audited by BA.
Join Date: Apr 2006
Location: London
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
JW411-I believe your transponder transmits on 1013,25/2992 all of the time and not on altimeter setting.ATC computer works out passing alt using the difference on QNH and standard pressure on the day.If you mean an alt verbal readout for a crosscheck with ATC use standby altimeter which is usually set to QNH for terrain clearance .
I think when cleared to a level one should set 1013 right away,also depends on your rate of climb etc.
An opinion only.........
I think when cleared to a level one should set 1013 right away,also depends on your rate of climb etc.
An opinion only.........
Bottums Up
Smoozesailing
The Australian Jeppesen Airways Manual (and AIP) are quite specific re where to set the altimeter.
We use QNH to 10,000', have a no-cruise layer, called the transition layer, between A100 and FL110 (depending on QNH) and Flight Levels above A100.
Jeppesen/ATC/AU-501/1.2.1.4
So in plain English, set 1013.2 at or after passing 10,000' on climb, and set QNH prior to FL110 on descent to any level at or below 10,000'
The Australian Jeppesen Airways Manual (and AIP) are quite specific re where to set the altimeter.
We use QNH to 10,000', have a no-cruise layer, called the transition layer, between A100 and FL110 (depending on QNH) and Flight Levels above A100.
Jeppesen/ATC/AU-501/1.2.1.4
The position to change between QNH & 1013.2 hPa shall always be in the Standard Pressure Region on climb after passing 10,000ft and prior to leveling off, or on descent to a level in in the Altimeter Setting Region prior to entering the Transition Layer.
Join Date: Jun 2004
Location: UK
Posts: 177
Likes: 0
Received 0 Likes
on
0 Posts
From UK AIP ENR 1.7
"When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been
specifically requested by Air Traffic Control.
When an aircraft is descended from a Flight Level to an Altitude preparatory to commencing approach for landing, ATC will pass the appropriate aerodrome QNH. On vacating the Flight Level, the pilot will change to the aerodrome QNH unless further Flight Level vacating reports have been requested by ATC, in which case, the aerodrome QNH will be set following the final Flight Level vacating report."
In general therefore, unless ATC request otherwise, you can change to STD as soon as cleared climb to a flight level, and you can change to QNH as soon as you commence descent to a cleared altitude.
Exeptions are:
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
"When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been
specifically requested by Air Traffic Control.
When an aircraft is descended from a Flight Level to an Altitude preparatory to commencing approach for landing, ATC will pass the appropriate aerodrome QNH. On vacating the Flight Level, the pilot will change to the aerodrome QNH unless further Flight Level vacating reports have been requested by ATC, in which case, the aerodrome QNH will be set following the final Flight Level vacating report."
In general therefore, unless ATC request otherwise, you can change to STD as soon as cleared climb to a flight level, and you can change to QNH as soon as you commence descent to a cleared altitude.
Exeptions are:
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
Thread Starter
Join Date: Jul 2001
Location: ITCZ
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
So......
that means that there are differences depending on the FIR you are flying in. Would it be safe to assume all JAA FIRs have the same rule? What about in North America? What about the rest of the world?
Jeppesen/ATC/AU-501/1.2.1.4
Quote:
The position to change between QNH & 1013.2 hPa shall always be in the Standard Pressure Region on climb after passing 10,000ft and prior to leveling off, or on descent to a level in in the Altimeter Setting Region prior to entering the Transition Layer.
So in plain English, set 1013.2 at or after passing 10,000' on climb, and set QNH prior to FL110 on descent to any level at or below 10,000'
Quote:
The position to change between QNH & 1013.2 hPa shall always be in the Standard Pressure Region on climb after passing 10,000ft and prior to leveling off, or on descent to a level in in the Altimeter Setting Region prior to entering the Transition Layer.
So in plain English, set 1013.2 at or after passing 10,000' on climb, and set QNH prior to FL110 on descent to any level at or below 10,000'
From UK AIP ENR 1.7
"When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been
specifically requested by Air Traffic Control.
When an aircraft is descended from a Flight Level to an Altitude preparatory to commencing approach for landing, ATC will pass the appropriate aerodrome QNH. On vacating the Flight Level, the pilot will change to the aerodrome QNH unless further Flight Level vacating reports have been requested by ATC, in which case, the aerodrome QNH will be set following the final Flight Level vacating report."
In general therefore, unless ATC request otherwise, you can change to STD as soon as cleared climb to a flight level, and you can change to QNH as soon as you commence descent to a cleared altitude.
Exeptions are:
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
"When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been
specifically requested by Air Traffic Control.
When an aircraft is descended from a Flight Level to an Altitude preparatory to commencing approach for landing, ATC will pass the appropriate aerodrome QNH. On vacating the Flight Level, the pilot will change to the aerodrome QNH unless further Flight Level vacating reports have been requested by ATC, in which case, the aerodrome QNH will be set following the final Flight Level vacating report."
In general therefore, unless ATC request otherwise, you can change to STD as soon as cleared climb to a flight level, and you can change to QNH as soon as you commence descent to a cleared altitude.
Exeptions are:
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
Transition Altitude and Transition Level will vary as a function of the terrain around the airfield.
So in UK for example, TA could be as low as 3,000 ft. (An exception is the London TMA where it is standardised at 6,000 ft).
Some countries have standardised TA on a countrywide basis. The USA has a standardised TA of 18,000 ft which I guess is the height of Mt St Helens + 1500 ft + 10% or some such formula. Therefore, you are safe changing at 18,000 ft wherever you happen to be in the USA. Certainly it keeps it simple.
So in UK for example, TA could be as low as 3,000 ft. (An exception is the London TMA where it is standardised at 6,000 ft).
Some countries have standardised TA on a countrywide basis. The USA has a standardised TA of 18,000 ft which I guess is the height of Mt St Helens + 1500 ft + 10% or some such formula. Therefore, you are safe changing at 18,000 ft wherever you happen to be in the USA. Certainly it keeps it simple.
Gender Faculty Specialist
Originally Posted by Rivet gun
Exeptions are:
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
You must have QNH set for take off and can't change to STD below flap retraction altitude.
At least one altimeter (e.g. the standby) should remain on QHN below MSA for terrain awareness.
Our company states that with a low QNH and an early level off (FL40) SPS can be set prior to take off and on both altimeters. This is usually covered in the brief and is at the Captains discretion. The standby, of course, remains on the QNH.
Join Date: Jan 2006
Location: In a far better place
Posts: 2,480
Likes: 0
Received 0 Likes
on
0 Posts
At one carrier during departure… the procedure is to set STD when cleared to a FL. The STBY altimeter would be set to 1013 when climbing above the MSA.
During descent… the altimeters would be set to QNH when cleared to an altitude unless FL crossing restriction was imposed by ATC. Then the altimeters would be set to QNH once the FL crossing restriction has been satisfied.
The bottom line is... who ever signs your paycheck controls the procedures you follow in the cockpit.
During descent… the altimeters would be set to QNH when cleared to an altitude unless FL crossing restriction was imposed by ATC. Then the altimeters would be set to QNH once the FL crossing restriction has been satisfied.
The bottom line is... who ever signs your paycheck controls the procedures you follow in the cockpit.
Join Date: Jan 2005
Location: Canada
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Most of you are applying the UK rules (which are an exception) to the rest of the world and are setting yourselves up for one lovely mid-air. The ICAO world wide standard is: "....except as authorized by ATC, aircraft progressing from one region to another shall make the change in the altimeter setting while within the standard pressure region prior to entering, or after leaving, the altimeter setting region." Capt Claret's outline of the rules in Oz mirror the ICAO standard with a TA of 10,000 and TL of FL110. Here in North America, 18,000 has been established as the TA continent wide (the far northern areas excepted) - nothing to do with terrain by the way. With an altimeter setting beloew 29.92", Canadian ATC will adjust the lowest useable flight level and the TL remains at FL180 but in the US the TL varies by 500' above for every .5" of altimeter below 29.92". Thus an altimeter setting of 29.43" in New York produces a TL of FL185. All of the above ensures that all aircraft operating in the same airspace are using the same altimeter setting/flying the same altitudes.
Imagine the scramble if departing practically any airport outside the UK, having been cleared to your high altitude cruise flight level and STD set, when ATC asks for an "IMMEDIATE level-off due traffic" at any altitude within the altimeter setting airspace and also stops the descent of the conflicting traffic 1,000 above. I challenge any of you to get the "rocket" under control without plastering all against the ceiling, look for the traffic and find/reset to the local altimeter setting. The UK rules leave the altitude separation problem to the controller - their job to keep the aluminum apart - and as I spend quite a bit of time in their airspace, I wish them much luck.
Imagine the scramble if departing practically any airport outside the UK, having been cleared to your high altitude cruise flight level and STD set, when ATC asks for an "IMMEDIATE level-off due traffic" at any altitude within the altimeter setting airspace and also stops the descent of the conflicting traffic 1,000 above. I challenge any of you to get the "rocket" under control without plastering all against the ceiling, look for the traffic and find/reset to the local altimeter setting. The UK rules leave the altitude separation problem to the controller - their job to keep the aluminum apart - and as I spend quite a bit of time in their airspace, I wish them much luck.
