Altimeter settings: QNH versus QFE

Just another point in this discussion: when I look at an approach map of
an airfield, the pattern altitude is expressed as a height above
ground. To me, this means the easiest way of complying is to fly QFE
when entering the pattern (no mathematics needed) - providing of course
you can get the necessary information.

If you want to fly QNH, pattern altitudes should be expressed AMSL.

By the way, here in Europe (except UK, of course) glider altimeters are
in meters, not feet, thereby conforming to ICAO annex 5 whose purpose
it is to standardize units of measurement to the ISU. As the approach
maps (and other aviation maps) usually are in feet, we already have to
make computations anyhow.

It's high time we got rid of feet, knots and nautical miles! Their only
real purpose in aviation seems to be to make it more difficult to get a
pilot's licence, as you have to adjust to a new set of units. (Yes, I
know there are certain countries where they like to use outdated unit
systems. I also know the classical arguments like "a nautical mile
equals a minute of latitude", but how often do you fly true north or
south?)


--
stephanevdv
------------------------------------------------------------------------
Posted via OziPilots Online [ http://www.OziPilotsOnline.com.au ]
- A website for Australian Pilots regardless of when, why, or what they fly -

All of the aruguing aside, can anybody out there tell me a little of
the history of QNH, QFE, and QNE (etc.), specifically, WHAT does the
"Q" stand for??? The "F"? The "N", the "H" or the "E"???

I can see reasons for using each and every setting, and I can see
reasons for NOT using each and every setting.

My opinion is that we should all learn to do the math (in both
directions), and I am not practicing what I've just preached (at least
when it comes to using QFE!).

Just wait until there's another mid-air, and suddenly all gliders are
required to be equipped with transponders, TCAS, ADS-B, radio
altimeters and "bitchin' betty's" to annoy pilots getting too close to
stall (or spin)...

Again, where did the "Q" come from???

-Pete
#309

Argg I specifically didn't want to go into this can of worms! (see the
original post). IFR approach plates (at least in the US, where QFE
isn't used) give all approach altitudes in QHN, hence the need for an
accurate and recent altimeter setting. VFR pattern altitudes are often
given AGL, but they are pretty consistent: 1000', 1500' for jets,
perhaps 800' for gliders, etc. It really doesn't require a calculator
in the cockpit to figure out what number to put behind the needle on
the altimeter to be at the right altitude in the pattern. And it is a
lot easier to figure out the proper pattern altitude than to go through
the hassle of getting the QFE setting - assuming the airfield you are
landing at is low enough. It's a moot point in the US - ask tower for
a QFE setting and all you will get is "huh, say again?".

I understand in Europe it is common to have two altimeters in power
planes so that one can be set to QFE. Makes sense for instrument/low
vis approaches (pre-radar altimeter), if the "system" is setup for it
(QFE available from tower, appropriate approach plates, proper training
etc). Is this a correct assumption?

As far as going metric in aviation, sorry but I absolutely disagree -
metric units just don't work as well in aviation as feet/knots/NM,
IMHO. Metric altimeters are an abomination! And since almost all the
big boys (general aviation, airlines and military) use feet/knots/NMs,
everybody should. There is nothing sacred about the meter, after all -
any arbitrary unit will do if it is used consistently and satisfies the
needs of the users. Not that I expect any agreement on this point from
my European friends!

And the nice thing about nautical miles is that it is extremely easy to
get a quick distance measurement off a sectional chart by using the
nearest latitude scale - regardless of heading. Especially when the
kilometer scale is buried under the folds of the chart (or is on the
piece that got torn off to make the chart small enought to use in an
LS6's cockpit!)

My pet peeve in the US is that we usually fly in feet/knots, but set
tasks and give XC speeds in statute miles/MPH, then use kilometers for
badge and OLC flights. Absurd!

Seriously, it's interesting that the responses to the original topic of
this thread have not included any real defenders of using QFE in
gliders, just some reasons (excuses?) why it is done. Cmon, let's hear
it from you guys who are teaching it to your students!

Cheers,

Kirk
66

309 wrote:

All of the aruguing aside, can anybody out there tell me a little of
the history of QNH, QFE, and QNE (etc.), specifically, WHAT does the
"Q" stand for??? The "F"? The "N", the "H" or the "E"???

Nothing. It's just a code, the Q-code, to be precise :-) Maybe the Q has
a story, I don't know, but the latter two letters definitely do not.
Think of it as a numbered set of commonly used phrases.

A complete list of all Q-codes is at http://www.htc.ch/de/der_Q_code.htm
(German only).

Stefan

I was introduced to the Q codes as an army cadet in the signals wing.
One of the wonderful ones that stuck in my memory all these years was
"Shall I point my searchlight at a cloud, occulting if necessary, in
order to pinpoint my position" All that in 3 letters! They were used
for morse code communications before RT was available.

Andy

In article .com,
"309" wrote:

All of the aruguing aside, can anybody out there tell me a little of
the history of QNH, QFE, and QNE (etc.), specifically, WHAT does the
"Q" stand for??? The "F"? The "N", the "H" or the "E"???

"Query". These are Morse radio operator's abbreviations for common
questions they might ask of or be asked by a ground station.

http://en.wikipedia.org/wiki/Q_code

QNH is I believe "Nautical Height" and QFE is "Field Elevation" though
these are more mnemonics than definitions. What is the difference
between height and elevation? If you know, please explain why QNE might
be "Nautical Elevation".. (some sources suggest the mnemonic "anywhere"
for NE)

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

stephanevdv wrote:
Just another point in this discussion: when I look at an approach map of
an airfield, the pattern altitude is expressed as a height above
ground.
The only ones I knew did that were the old Aeradio ones published for BA
when they used QFE. Never seen a Jepp chart in QFE - but I guess
they're produced that way for some operators.

If you want to fly QNH, pattern altitudes should be expressed AMSL.
They almost always are on the charts I've seen.

By the way, here in Europe (except UK, of course) glider altimeters are
in meters, not feet, thereby conforming to ICAO annex 5
True. But in non-conformity to the great bulk of aviation globally. A
classic example of the problems of one-nation one-vote in these matters.

BTW - Aren't your altimeters in metres, not meters?

whose purpose
it is to standardize units of measurement to the ISU
No. Its purpose is just to standardise measurements. Feet are
perfectly good units to standardise on.

. As the approach
maps (and other aviation maps) usually are in feet, we already have to
make computations anyhow.
Well stop resisting. Learn to think in feet instead of metres.

It's high time we got rid of feet, knots and nautical miles! Their only
real purpose in aviation seems to be to make it more difficult to get a
pilot's licence, as you have to adjust to a new set of units. (Yes, I
know there are certain countries where they like to use outdated unit
systems. I also know the classical arguments like "a nautical mile
equals a minute of latitude", but how often do you fly true north or
south?)

ICAO working document(23/9/04): "...a study...completed in 1997,
indicated that 97% of jet aircraft worldwide were non-SI equipped
aircraft. Moreover, a growing number of non-SI equipped aircraft were
being operated by airlines of the small number of States which use SI
units."

You'll be flying in feet, knots and nautical miles for quite a while.
Better relax and go with the flow.

GC


--
stephanevdv
------------------------------------------------------------------------
Posted via OziPilots Online [ http://www.OziPilotsOnline.com.au ]
- A website for Australian Pilots regardless of when, why, or what they fly -

309 wrote:

All of the aruguing aside, can anybody out there tell me a little of
the history of QNH, QFE, and QNE (etc.), specifically, WHAT does the
"Q" stand for??? The "F"? The "N", the "H" or the "E"???

The three letter "Q" codes date back to W/T, radio operators and Morse
code. They were a shorthand way of requesting/passing information and I
don't recall any where the other letters have any significance.

The only others I remember still in use are QDM - ILS inbound track or
runway direction and QSL - followed by a number to indicate radio signal
strength or readability.

Others (especially radio hams) may remember a lot more.

GC

Todd,

I was referring to the part of my original post where I said: "And
please, no tangential discussion about using QFE for IMC approaches
- unless you have two altimeters in your glider..." since I had a
feeling it would crop up and divert attention from the issue at hand.

As far as the pseudo QFE - amazing what some people will do to avoid
doing a little thinking in the cockpit.

Great discussion by all involved - I guess I'll just have to bite the
bullet and become a CFIG so I can impose my will on others!

Kirk

stephanevdv wrote:

I also know the classical arguments like "a nautical mile
equals a minute of latitude", but how often do you fly true north or
south?)

How often do you look at a map?


Jack