Qnh, Qne, Qfe??

[loNslo]

What exactly does QNE, QNH, QFE mean? I tried to explain it to an associate of mind and wound up just confussing both of us. It's been a while since I've used these terms. Thanks

 

[gnx99]

Try this (bottom of the page)
http://www.booty.demon.co.uk/metinfo/isa.htm

 

[bigsky]

In laymens terms:
Qnh: what we are most used to in the USA with light aircraft. As long as we have the current altimeter setting we will indicate height above M.S.L.
QNE: in the USA at and above 18000 (transition) we display 29.92 or P.A. Note in most other countries transition is much lower and varies from airport to airport- usually 5000-8000 feet.
QFE is an altimeter setting that will display zero when the aircraft touches down or airport elevation. Still used in China and parts of former Soviet Union.

 

[bobbysamd]

QNH, et al

Further to the above, I believe that these are ICAO terms. The military may use them as well.

 

[FearlessFreep]

After learning the difference between QNH, QNE & QFE there are two other important factors to understand, these being "Transition Level" & "Transition Altitude".

Here in the states we use just one, commonly referred to as the transition level which in fact is both the transition level and transition altitude. At 18,000' we set QNE (29.92) when ascending and QNH (current local altimeter setting) when descending.

Overseas there might be two different altitudes and they might change according to notices or altimeter setting.

Basically remember this,

Climbing through the "Transition Altitude" set QNE

Descending through the "Transition Level" set QNH

I just mentally associate "altitude" with "ascent" to keep differentiated between the two transitions.

 

[skiddriver]

These Q-codes are from the old radio-telegraph days when info was sent over the radio using a Morse code key. Once upon a time, a radio-telegraph operator was a normal member of airline crews. I think it's interesting (if anachronistic) that we still use these terms. Here's just a couple links that explain their origin, though you can find a lot more by doing a web search on "Q-codes".

http://www.computerpilot.com/readerarticles/qcodesresponse.htm

http://www.computerpilot.com/readerarticles/qcodes.htm

http://www.kloth.net/informations/qcodes.htm

 

[airtoair]

I've also been told QNH = Queen's Nautical Hands??? ( A wise man once told me)

 

[bigsky]

FearlessFreep had a good point. On most foreign approach plates you will find transition altitude listed. This is the altitude where you switch to 29.92 during climb/ascent. The transition level will normally be given by ATC or on atis. It is not the same altitude as in the USA- but will normally be 1000/2000 feet higher.( for example the chart says TA 5000 and ATC will call TL 7000) I havent figured out why they do it that way and we dont as our single transition works pretty well and is one less thing to worry about on the busy arrival or approach.

 

[loNslo]

Thanks for all the great info. It has provided a good review.

 

[AAflyer]

One other point. With the setting of altimeter in Europe through a transition altitude and level set it in Millibars, that is normally what is given. Trying to compute the two can lead to error. Think MB!!!!

AAflyer

Till 1998 AA used QFE here in the US!! Thank goodness I missed that.

 

[PilotoHalcon]

Here is Western Asia we use transition altitudes and transition levels also. Bigsky, you will also find the altitudes and the appropriate high chart. For here it is FL150, except for UAE which is FL145, go figure.
j

 

[bigsky]

I was not aware of that! Are those NoAA charts or Jepps/ or both?

 

[rudedog]

<< What exactly does QNE, QNH, QFE mean? I tried to explain it to an associate of mind and wound up just confussing both of us. It's been a while since I've used these terms. Thanks >>

loNslo,

Heres' how I remember them:

Q = Q
N = Normal
H = Height


Q = Q
N = Normal
E = Enroute


Q = Q
F = Field
E = Elevation


The rest is from 'bigsky':

"In laymens terms:

QNH: what we are most used to in the USA with light aircraft. As long as we have the current altimeter setting we will indicate height above M.S.L.

QNE: in the USA at and above 18000 (transition) we display 29.92 or P.A. Note in most other countries transition is much lower and varies from airport to airport- usually 5000-8000 feet.

QFE is an altimeter setting that will display zero when the aircraft touches down or airport elevation. Still used in China and parts of former Soviet Union."

 

[PilotoHalcon]

Bigsky, the charts we use are the DOD/NIMA ones, and only on the high chart. Not on the lows for some reason. I have not seen a Jepp here so I have no idea what they have on them. Rudedogs way of remembering them is also the way I remember them.
j