where does "QNH" come from?
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Akro,
I don't know if I believe it myself but I read that it has to do with the high mountains (compared to most areas in Europne) in the US. Altitude until well above all that cumulogranitus, FLs after that.
Personally, I find what Nick is saying more believable.
Hmm, I can imagine that sectors (in this case significant as areas with the same QNH) tend to be larger in the US as well, making HOVs and flying on altitude less of a PITA?
Any other suggestions?
Cheers,
/ft
I don't know if I believe it myself but I read that it has to do with the high mountains (compared to most areas in Europne) in the US. Altitude until well above all that cumulogranitus, FLs after that.
Personally, I find what Nick is saying more believable.
Hmm, I can imagine that sectors (in this case significant as areas with the same QNH) tend to be larger in the US as well, making HOVs and flying on altitude less of a PITA?Any other suggestions?
Cheers,
/ft
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ft,
Sounds like a good reason even though I don't really believe it myself since I come from Switzerland (and as you might know we've got some high "cumulusgranitus" around as well). Here same rule applies as in the rest of Europe (at least AFAIK). So there must be another "good" reason why we do it like this over here (unless the yankees are really smarter
).
Sounds like a good reason even though I don't really believe it myself since I come from Switzerland (and as you might know we've got some high "cumulusgranitus" around as well). Here same rule applies as in the rest of Europe (at least AFAIK). So there must be another "good" reason why we do it like this over here (unless the yankees are really smarter
).
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'Q' was probably only used to be distinctive, with no real meaning, any more than the military used 'Z'. I doubt very much that many of the code groups were ever self evident, but of course after the event you can dream up anything to fit. Q codes were not just questions since the meaning could change between transmission and reply, one meaning "Am I...?" and the other "You are..." or "What is?" and the appropriate reply would be prefixed the same. IE QDM - "What is my bearing" and "Your bearing is...." and no doubts about whether it is from/to, magnetic or true, Spanish or French etc, etc.
Such code forms were, and may still be, necessary to ensure quick and umambiguous interpretation of critical information. The use of the word 'altimeter' (not uncommon in the 'States) is a hazard if the recipient doesn't know if it really means QNH, QNE, or QFE and transmitted between persons without a common natural language. There were also several other Q,s for altimeter. The use of Q code is clear, easily used and unambiguous.
Q code was not limited to W/T nor three letters. Teletype time was much improved and clarified by the same form. NOTAM code was (is?) Q and came in five letter groups. This may illustrate the point, since a single group could explain the whole NOTAM irrespective of the language it was decoded in. I can't recall any proper code groups, typically something like QNBOS might mean Q-(use the Q book), NB-(NDB) OS-(out of service), and would do so in English, Russian, Chinese or anything else. Some two-letter encodes were self evident but most were not.
Not everything the Ancients did was stoopid.
Such code forms were, and may still be, necessary to ensure quick and umambiguous interpretation of critical information. The use of the word 'altimeter' (not uncommon in the 'States) is a hazard if the recipient doesn't know if it really means QNH, QNE, or QFE and transmitted between persons without a common natural language. There were also several other Q,s for altimeter. The use of Q code is clear, easily used and unambiguous.
Q code was not limited to W/T nor three letters. Teletype time was much improved and clarified by the same form. NOTAM code was (is?) Q and came in five letter groups. This may illustrate the point, since a single group could explain the whole NOTAM irrespective of the language it was decoded in. I can't recall any proper code groups, typically something like QNBOS might mean Q-(use the Q book), NB-(NDB) OS-(out of service), and would do so in English, Russian, Chinese or anything else. Some two-letter encodes were self evident but most were not.
Not everything the Ancients did was stoopid.
Man of the Marsh
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This one comes round on PPRuNe from time to time and even receives some interesting answers. There was a thread on Tech Log back in July 1999 which is worth reading:
The Q things
Hope this helps, go with the flow.
The Q things
Hope this helps, go with the flow.
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I have been told on good authority that the NH stands for 'Nautical Height'.
ATC only measure QFE. QNH a calculated figure.
In otherwords ATC know the airfield pressure setting (QFE) and due to the known elevation of the airfield above sea level they can calculate the QNH by subtracting the known difference from the QNH to arrive at the QFE figure.
MG
ATC only measure QFE. QNH a calculated figure.
In otherwords ATC know the airfield pressure setting (QFE) and due to the known elevation of the airfield above sea level they can calculate the QNH by subtracting the known difference from the QNH to arrive at the QFE figure.
MG
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Just to add to all these, does any country use QDR and QDM for tracking. ATC in my country for non radar environment aerodrome uses these q codes. They usually will ask us to track on the QDR of a navaid. The misconception here is that it is assumed that a QDR is the radial inbound to the navaid when in fact a QDR is a bearing to the station no matter where you are heading and the QDM is the heading to steer in nil wind to the station. Can anyone enlighten me on this.
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...a QDR is a bearing to the station no matter where you are heading
The QDR is the magnetic bearing from the station. A QDR from an NDB is "the same as" a radial form a VOR. A QDM to an NDB is "the same as" an inbound course to a VOR.
The track (or "position") of QDR 190 is exactly the same as QDM 010.
And, as you say, this is irrespective of the aircraft's heading or direction of flight, but it applies both for QDMs and QDRs.
Nick.
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There is a pretty definitive listing of Q codes here.
http://www.qsl.net/ka1axy/q_sigs.txt...axy/q_sigs.txt
Akro
Don't fall into the trap of thinking that QNE is the Standard setting of 1013.2 or 29.92. QNE is the indication (in feet or metres) which will be shown on your altimeter at an airfield when that pressure is set. You won't find many airfields above 18,000' to land at to try it out, even in the US
[ 13 August 2001: Message edited by: PPRuNe Radar ]
http://www.qsl.net/ka1axy/q_sigs.txt...axy/q_sigs.txt
Akro
Don't fall into the trap of thinking that QNE is the Standard setting of 1013.2 or 29.92. QNE is the indication (in feet or metres) which will be shown on your altimeter at an airfield when that pressure is set. You won't find many airfields above 18,000' to land at to try it out, even in the US
[ 13 August 2001: Message edited by: PPRuNe Radar ]
ENTREPPRUNEUR
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I think these were dialogues rather than values.
Eg QNE
Aeroplane Radio Operator "QNE LHR 1230" (= What will the altimeter reading be for London at 12:30 if 1013.2 is set?)
ATC "QNE LHR 128 FT" (= The altimeter reading for London at 12:30 will be 128 feet)
Eg QNE
Aeroplane Radio Operator "QNE LHR 1230" (= What will the altimeter reading be for London at 12:30 if 1013.2 is set?)
ATC "QNE LHR 128 FT" (= The altimeter reading for London at 12:30 will be 128 feet)
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I have made a cursory search of the grey matter and I brought up some long time (and somewhat vague) memories on ATPL groundschool
on transition levels/altitudes. Are they not based on an altitude that clears all obstacles within the prescribed area by a minimum amount(formula used, min clearance increased with height of terrain), and are therefore terrain dependent?
When the formula is applied, it gives the maximum number of available flight levels as governed by terrain limitations.
On the other hand, it's been so long I might be mixing it up with something else.
on transition levels/altitudes. Are they not based on an altitude that clears all obstacles within the prescribed area by a minimum amount(formula used, min clearance increased with height of terrain), and are therefore terrain dependent?
When the formula is applied, it gives the maximum number of available flight levels as governed by terrain limitations.
On the other hand, it's been so long I might be mixing it up with something else.
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In the USA, "altimeter setting" always means QNH. Inches are always used. Above 17,500, altimeters are always set to 29.92 inches. QFE used to be used by Eastern and American Airlines, and they would get their QFE from their company radio, since the ATC facilities didn't even have it available. Even on approach, they kept a third altimiter set to QNH. Most pilots in the USA don't know the meaning of QNH or QFE, etc., since we don't use the three letter Q codes. The 5 letter ones are used in NOTAMS, which in our politically correct times are referred to as NOTACS (C is for crew).
By the way, ATIS means Airport Terminal Information Service.
By the way, ATIS means Airport Terminal Information Service.
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SOMETIMES A LOT OF ****E GETS PUBLISHED ON THESE PAGES...AND WITH THE EXCEPTION OF "KERMIT 180" ALL OTHERS APART FROM "bEAGLE" SHOULD BUY ME A BEER.
The "Q" in "Q" code stands for "QUEEN'S
QNH..."QUEEN'S NATURAL HEIGHT"
QFE..."QUEEN'S FIELD ELEVATION"
QNE..."QUEEN'S NATURAL ELEVATION"
QDM..."QUEEN'S DIRECTIN MAGNETIC" etc..etc..etc..TR3
[ 07 September 2001: Message edited by: TR3 ]
The "Q" in "Q" code stands for "QUEEN'S
QNH..."QUEEN'S NATURAL HEIGHT"
QFE..."QUEEN'S FIELD ELEVATION"
QNE..."QUEEN'S NATURAL ELEVATION"
QDM..."QUEEN'S DIRECTIN MAGNETIC" etc..etc..etc..TR3
[ 07 September 2001: Message edited by: TR3 ]
