Altimeter settings: QNH versus QFE

I'd like to add that for aerobatic flight, it is common to use QFE, for
obvious reasons. But then, aerobatic flights are usually strictly local.

Stefan

Flying for 10 years over Northern Germany (which, except for the climate,
could be compared to Northern Florida) I always used a QFE setting with the
field 600ft MSL. Airspace regulations weren't that touchy in these days, and
sailplane altimeters aren't that precise anyways so there is just no point
to have it set at 400ft or 600ft. If you rely on judging your altitude by an
altimeter during the pattern for an outlanding, you shouldn't go x-country
in the first place. If you run into a high antenna or a tower on a hillside,
you should think about getting a new prescription for your glasses.

The last 15 years in the mountains are another story though.

--
Bert Willing

ASW20 "TW"


"Stefan" a écrit dans le message de news:
...
Kilo Charlie wrote:

How about mountains? How about large towers there in the "flatlands"
where elevations can vary even there

How about looking out of the window?

Stefan

I've yet to see a glider with an accurately calibrated altimeter.

Strange.
As they are supposed to be certified instruments, they are required to be
checked every two years here in New Zealand. Along with the Transponder and
encoder.
Paul

I was taught to fly in meters above ground and do a mental conversion
by multiplying the meters by three and adding 4 500ft to get the real
altitude when speaking to the ATC. I then bought a glider without a
meter altimeter - only a ft one which is set to show altitude above sea
level. No more problem when speaking to ATC but found I was doing
reverse calculations to find out how high I was above the hard stuff.
Then I set my palm up with Soaringpilot which now has a digital terrain
model built in. Now I know exactly how high I am above the ground -
even when I fly cross-country in the mountain regions not far from my
airfield. My LX 5000 computer is set up to show my height above my home
field, which is more important for final glide than anything else.

Clinton Birch
LAK 12

In message , T o d d P a t t
i s t writes
"BTIZ" wrote:

Best to learn the mental math now.. then later when you travel west for the
first time.

I agree 100%.
It has been really interesting to watch this one. I fly in the UK and
this is what I have been taught to do:

If local then QFE;
if XC then QNH;
If wave flying then QNE once you go above 3,500 QNH (this is transition
round where I am I know it is different in other places). This also
applies XC if you are going near a lot of airspace;

I am taught to land without reference to the altimeter and I don't think
I have ever used it when I carry out field landings.

Not that many glider pilots in the UK have radio licences and a fair
number of gliders do not have radios so the QNH is not generally updated
beyond the departure calculation and setting.

Now, I must say that this is a reworking of what I was taught for power,
not gliding and I can't remember it ever being laid down specifically
what I should do away from local flight other than making sure that I
could land and so on without use of the altimeter.

Cheers

Robin
--
Robin Birch

T o d d P a t t i s t wrote:
It's my understanding that this procedure is also used in
airplanes in the U.K. In the U.S., airplanes will only use
QNH or QNE (above 18,000') and never use QFE.

There is always an exception to any rule. American Airlines used to
always use QFE set altimeter for approach and landing in US. I was
involved in the development of the MD-11. We developed an altimeter
setting system that allowed easy transition between QFE, QNH and STD
for the glass cockpit altimeters. American was the only US operator
that used that customer option. They would land at Denver with
altimeter reading zero after getting QFE setting from local ground ops.
(I was involved in development and flight test, not American's ops, so
any America Airlines pilots on this forum may correct this).

Andy

it better be... if the transponder is installed..
BT

"Stefan" wrote in message
...
BTIZ wrote:

you do.. you listen to the local ATIS or ASOS or AWOS or check with FSS
or ATC on freq and find out what they are using in the local area

I've yet to see a glider with an accurately calibrated altimeter.

Stefan

BTIZ wrote:
it better be... if the transponder is installed..
BT

"Stefan" wrote in message
...

BTIZ wrote:


you do.. you listen to the local ATIS or ASOS or AWOS or check with FSS
or ATC on freq and find out what they are using in the local area

I've yet to see a glider with an accurately calibrated altimeter.

When I had my biennial check on my transponder, there was no check of
the altimeter. They did adjust the encoder to read the current pressure
altitude. I know there are strict requirements for encoder and altimeter
accuracy for IFR flight, which requires testing the encoder and
altimeter up to the altitude they will be used in. Is there some
regulation requiring an aircraft with a transponder used in VFR flight
to also have an altimeter calibration? I don't think Mode C is required,
so perhaps the regulation, if there is one, applies only if an encoder
is installed?



--
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Eric Greenwell
Washington State
USA

I admit to not being up on the current FAR's re altimeters but is there no
regulation for all aircraft in the US to have accurate altimeters?

I would like to think that mine is accurate within a certain limit since as
this discussion points out it is important. No doubt that in the conditions
that we fly in (changing pressure as the day progresses) there is some
inaccuracy but in my experience not more than a hundred feet or so and as
others have pointed out by tuning in to a local ATIS can be corrected.
Those influences are the same for whatever setting you decide to initially
use anyway.

Casey Lenox
KC
Phoenix

transponders 91.217, and 91.413

91.413 specify a 24 month check even if used for VFR only for the
transponder to report accurate altitude

AIM 7-2-3, check altimeter against know field elevation and baro setting, if
difference is greater than +/- 75ft from the known elevation. The altimeter
accuracy is suspect and should be reported to a repair station for
evaluation and correction.

The altimeter and transponder must be checked every 24 months for operations
in IFR. (91.411)

That is the only VFR "check" of the altimeter that I have found tonight. But
if the altitude or altitude reporting function (blind encoder) reports
altitude to the transponder, it must be checked every 24 months. If you
don't have a transponder, and you never fly IFR, if the baro setting
displays within 75ft of field elevation. It's "good to go".

BT

"Eric Greenwell" wrote in message
...
BTIZ wrote:
it better be... if the transponder is installed..
BT

"Stefan" wrote in message
...

BTIZ wrote:


you do.. you listen to the local ATIS or ASOS or AWOS or check with FSS
or ATC on freq and find out what they are using in the local area

I've yet to see a glider with an accurately calibrated altimeter.

When I had my biennial check on my transponder, there was no check of the
altimeter. They did adjust the encoder to read the current pressure
altitude. I know there are strict requirements for encoder and altimeter
accuracy for IFR flight, which requires testing the encoder and altimeter
up to the altitude they will be used in. Is there some regulation
requiring an aircraft with a transponder used in VFR flight to also have
an altimeter calibration? I don't think Mode C is required, so perhaps the
regulation, if there is one, applies only if an encoder is installed?



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Eric Greenwell
Washington State
USA