modesto2
Posts: 2681
Joined: Sun Jul 16, 2000 3:44 am

QNH

Tue Oct 10, 2000 3:34 pm

I know QNH refers to the altimeter setting. However, is it an acronym? And if so...for what? If not, what is the significance of these three letters. Thanks.
 
Buff
Posts: 1066
Joined: Fri Mar 16, 2007 1:29 pm

RE: Q Codes

Tue Oct 10, 2000 10:41 pm

http://www.omen.net.au/~vk6wia/m-qcodes.html

I looked for about 20 minutes but couldn't find the old ICAO Q Codes. Perhaps you could start with this link from Oz.

I'm not old enough to remember it's common use in aviation, but I have seen an ICAO Convention with a couple of hundred aviation-related Q Codes, such as the QNH you've asked about. Maybe someone else has a good link.

Briefly, they date back to old radio practice, and Morse Code. Surely there are some (other) hams here to go down that road!

Best Regards,

Buff
 
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RE: QNH

Wed Oct 11, 2000 12:42 am

I don't think QNH stands for anything. It's just a code to indicate altimeter settings.

BTW, here's another link on Q-codes that includes an explanation of QNH.

http://www.wemsi.org/qsigs.html

Best Regards,
Nut
 
Aer Lingus
Posts: 1217
Joined: Sun May 14, 2000 4:06 am

RE: QNH

Wed Oct 11, 2000 3:36 am

As far as I can remember, the Q codes as they were known, herald from the war days when it was easier to say QNH, QFE & QNE rather than the full phrase. Even in writing it would be quite a mouthful, just imagine what it would be like on the radio.

Martin
 
archie
Posts: 216
Joined: Mon Aug 07, 2000 7:58 am

RE: QNH

Mon Oct 16, 2000 11:46 am

I think the Q codes were used because in the old days they used morse code so it was faster to type QNH in morse code than writing the whole phrase to ask what is the altimeter setting?
That is what I was told once but I don´t know if it is true.
Can anyone confirm this theory?
Thanks
Archie
 
zee73
Posts: 16
Joined: Fri Sep 16, 2016 8:14 am

Re: QNH

Sat Oct 29, 2016 7:16 am

QNH =Queens natural height,QNE=queens natural elevation ,QFE =Queens feild elevation ,
or u can use qubec instead of queen
 
SAAFNAV
Posts: 366
Joined: Wed Mar 17, 2010 5:41 pm

Re: QNH

Sat Oct 29, 2016 9:08 am

zee73 wrote:
QNH =Queens natural height,QNE=queens natural elevation ,QFE =Queens feild elevation ,
or u can use qubec instead of queen


Not even close. Useful way to remember what they are, but as stated above, in the old days or Morse Code, there was a whole list of Q-Codes.

It could be used as either a question or a reply, cutting out a lot of chatter.

https://en.wikipedia.org/wiki/Q_code
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OzzyPirate
Posts: 27
Joined: Fri Jul 15, 2016 2:27 am

Re: QNH

Sat Oct 29, 2016 9:49 am

There are hundreds of military Z and Q signals that have significance when applied to Morse transmission. QNH is one of them... I've heard people say the NH stands for "Nil Height", this terminology isn't technically correct, and it may be untrue (it's nil altitude, not height), but there might be some history there. Either way, it's a 3 letter Q signal that could be sent quickly via Morse.
 
BravoOne
Posts: 1454
Joined: Fri Apr 12, 2013 2:27 pm

Re: QNH

Sat Oct 29, 2016 1:08 pm

Both Archie and Zee73 are spot on.
 
SAAFNAV
Posts: 366
Joined: Wed Mar 17, 2010 5:41 pm

Re: QNH

Sat Oct 29, 2016 3:52 pm

BravoOne wrote:
Both Archie and Zee73 are spot on.


Explain:

What does the Queen have to do with it?

Where does natural come in?

Define natural?

QNH shows altitude, which is defined as a vertical distance from Mean Sea Level.

QNE is a fixed deviation from ISA Standard Conditions.

QFE set will show you height above ground, which is per definition of the term 'height'.

So, even if you insist on using the Queen, the rest of the definitions doesn't fit.
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26point2
Posts: 835
Joined: Wed Mar 03, 2010 6:01 am

Re: QNH

Sat Oct 29, 2016 4:37 pm

Surprises me that QFE is used any more these days. Do some airlines still mandate use of QFE on every approach as they used to? Does American Airlines still use QFE?
 
BravoOne
Posts: 1454
Joined: Fri Apr 12, 2013 2:27 pm

Re: QNH

Sat Oct 29, 2016 6:16 pm

26point2 wrote:
Surprises me that QFE is used any more these days. Do some airlines still mandate use of QFE on every approach as they used to? Does American Airlines still use QFE?



Both AA and the former EAL stopped using QFE many years ago. QFE is mainly used in the PRC, Mongolia, along with Russian states. In many cases you will see a statement on the approach plate that say "QNH on Request." Having said that there is line of thinking that says, "When in Rome, do as the Romans do" so different operators may use different procedures. The fact that the FMC and Nav Displays can be configured to use either QNH or QFE goes along ways in keeping aircraft out of the dirt.
 
BravoOne
Posts: 1454
Joined: Fri Apr 12, 2013 2:27 pm

Re: QNH

Sat Oct 29, 2016 6:18 pm

26point2 wrote:
Surprises me that QFE is used any more these days. Do some airlines still mandate use of QFE on every approach as they used to? Does American Airlines still use QFE?



I guess you must feel argumentative this morning:)
 
BravoOne
Posts: 1454
Joined: Fri Apr 12, 2013 2:27 pm

Re: QNH

Sat Oct 29, 2016 7:17 pm

Sorry my previous post was directed to SAAFNAV. I assume he is a current or former South African Air Force Navigator and if so, must experience using QFE along with the rest of the Q Codes.
 
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XAM2175
Posts: 389
Joined: Thu Oct 30, 2014 2:25 pm

Re: QNH

Sun Oct 30, 2016 9:32 am

I feel compelled to point out that zee73 has answered a thread that was last posted to sixteen years ago.
 
BravoOne
Posts: 1454
Joined: Fri Apr 12, 2013 2:27 pm

Re: QNH

Sun Oct 30, 2016 1:34 pm

XAM2175 wrote:
I feel compelled to point out that zee73 has answered a thread that was last posted to sixteen years ago.



No problem, as time goes by so fast at my age:)
 
Viscount724
Posts: 19287
Joined: Thu Oct 12, 2006 7:32 pm

Re: QNH

Mon Oct 31, 2016 4:04 am

XAM2175 wrote:
I feel compelled to point out that zee73 has answered a thread that was last posted to sixteen years ago.


It would be polite and helpful to other members if people would mention it when they resurrect old threads. And how do they even find such an old thread?
 
SAAFNAV
Posts: 366
Joined: Wed Mar 17, 2010 5:41 pm

Re: QNH

Mon Oct 31, 2016 2:22 pm

BravoOne wrote:
Sorry my previous post was directed to SAAFNAV. I assume he is a current or former South African Air Force Navigator and if so, must experience using QFE along with the rest of the Q Codes.


Well, up to today I was a C-130 navigator.

We did get trained during ab initio training on all the Q-codes and in SA some of them are still used in MET reports for take-off data.

We never use QFE, but I've heard that survey and agricultural aircraft uses it.
A majority of airfields in SA is above 4 000' AMSL, so I doubt if you could even set QFE on older mechanical altimers without running off-scale.
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zee73
Posts: 16
Joined: Fri Sep 16, 2016 8:14 am

Re: QNH

Tue Nov 01, 2016 9:34 am

Hi Friends how are u all ,1st of all im like a born baby in aviation industry so please dnt get upset due to my post as i said im new so i do surf on this website pages to learn from your experiences ,as far as i remember i found Qcodes online which mention that it used to use in early time of aviation and it comes from maritime and also said that u can use QUEENS/QUBEC or NORMAL/NATURAL ,if u google QCODES i hope u will find this type of documents and thanks to share ur experience and made me correct CHEERs
 
Pihero
Posts: 4237
Joined: Mon Jan 31, 2005 5:11 am

Re: QNH

Tue Nov 01, 2016 11:29 am

Funny how history gets transformed / distorted .
1/- There wasn't / has never been a good mnemotechnic method for remembering the meaning of each code as their definition was highly accurate and putting the queen in that sacred technique was at least a waste of time, at most a dangerous endeavour.
For instance, QNH means : "setting on the subscale of my altimeter so that the instrument would indicate its elevation if my aircraft were on the ground at your station"
the hidden characteristic is that setting , as it is already on an instrument, has already been corrected of all instrumental errors : temperature / instrumental...etc...
As a matter of fact, that value was only good for the airfield weather station, another close one would have another setting.

2/- QNE is defined as :" indication will my altimeter give on landing at ... (place) at ... hours, my sub-scale being set to 1013.2 millibars (29.92 inches)"
As a matter of fact, we have then two very accurate meanings of QNE :
2.a/- the airfield presure altitude
2.b/- the value one would dial on a Kollsman altimeter( for instance ) so that the altimeter would read 0 ft upon landing

3/- QFE was in general use until short range radio altimeters became more and more reliable, and the use of the QNH, with normally short setting differences with standard would lessen the risk of a setting mistake.

4/- The procedure was in fact very simple and quick : the query came as a question and the message would just be (for instance) "what's the QNH at your field ? = / QNH IMI / or DAA DAA DI DAA DAA DI DI DI DI DI DI DI DAA DAA DI DI (the question mark group transmitted without spaces)
By the way, one could fly an instrument approach with Qs and morse.

Last time I used morse and Q codes was in 1978 on a night flight to Kiev.
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