Altimeter setting

I was never confused until reading this thread...

The only valid use I can think of for using QFE is for low-level airshows,
e.g., inverted robbon cut.


"glidergeek" wrote in message
...
On Jan 26, 4:33 am, Tom wrote:
As a glider pilot, when are you allowed to use a zero altimeter
setting?

Back in July, I asked the FAA for a legal opinion regarding FAR
91.121. Yesterday, I finally received a response.

There is reason for a continued dialog, and I am continuing the
discussion with the FAA legal department.

This Saturday, immediately prior to the third Glider Safety Webinar,I
will provide subscribers to the webinar the exact wording of the FAA
response.

To join us in this discussion, please sign up for the third webinar on
our web site:www.eglider.org

Tom Knauff

If there is confusion it's because of an instructor not teaching
properly

This letter is in response to your July 19,2011 request for a legal
interpretation regarding
altimeter settings required in 14 CFR § 91.121. In your letter, you
state that there is
confusion among local area glider pilots as to whether altimeters must
be set to mean sea
level (MSL) when not using a cruising altitude, such as when
conducting student glider
flight training. Additionally, you indicate that glider operators are
unsure if the regulation
requires altimeters to be set to mean sea level (MSL) or above ground
level (AGL) during
student training and local flying.
The cruising altitude of an aircraft below 18,000 feet MSL shall be
maintained by
reference to an altimeter that is set to the current reported
altimeter setting of a station
located along the route of flight and within 100 nautical miles of the
aircraft. If there is no
such station, the current reported altimeter setting of an appropriate
available station shall
be used. In an aircraft having no radio, the altimeter shall be set to
the elevation of the
departure airport or an appropriate altimeter setting available before
departure. 14 CFR §
91.121(a)(1).
The cruising altitude is the MSL altitude or flight level maintained
during en route level
flight. For aircraft such as gliders, transient periods oftime at a
particular altitude do not
relieve pilots from the requirements to operate the aircraft in
reference to an altimeter that
is set according to the requirements of § 91.121(a). Thus, local area
glider pilots must set
their altimeters to MSL, not AGL, during glider operations, including
student glider
training flights.
Further FAA guidance on altimeter settings for glider operations can
be found in the Glider
Flying Handbook, FAA-H-8083-13, Chapter 4 (available online at
http://www .faa. gov/library/manuals/ aircraft! glider handbook/media/
faa-h-8083-13. pdf

The one situation where setting the altimeter to "zero' before flight
makes sense is flying a purely aerobatic flight. You will never be
towed high enough to bust airspace rules. You must be totally focused
on how high you are above the ground and to make sure you do not bust
the 1,500 floor for aerobatic flight. With so much going on in the
cockpit, setting the altimeter to zero makes the scan of the panel
very simple.

At 05:25 29 January 2012, guy wrote:
The one situation where setting the altimeter to "zero' before flight
makes sense is flying a purely aerobatic flight. You will never be
towed high enough to bust airspace rules. You must be totally focused
on how high you are above the ground and to make sure you do not bust
the 1,500 floor for aerobatic flight. With so much going on in the
cockpit, setting the altimeter to zero makes the scan of the panel
very simple.


I am coming to this thread late , but when I started we set QFE because we

only winch launched to 800ft and timed the flight in minutes and
seconds,you
new where you were going to land and when. Every thing has changed for me
,I now won,t rig if it is not soar able and always fly QNH ,but I still
like QFE
set for the first 3or4minutes till I am sure the rope isn't going to
break.But
then it,s a different world now the LX has QNH and AGL on the screen and
All
you need to do is re-set off tow.It is still nice to have QFE set for your

competition finish and I will re-set especially if control is giving it as
you call
5 minutes.

On Sat, 28 Jan 2012 21:25:13 -0800, guy wrote:

The one situation where setting the altimeter to "zero' before flight
makes sense is flying a purely aerobatic flight. You will never be
towed high enough to bust airspace rules. You must be totally focused
on how high you are above the ground and to make sure you do not bust
the 1,500 floor for aerobatic flight. With so much going on in the
cockpit, setting the altimeter to zero makes the scan of the panel very
simple.

Its also quite comforting if you're a flat-land flier and visiting a hill-
top site for a spot of ridge soaring.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

It is still nice to have QFE set for your
competition finish and I will re-set especially if control is giving it as
you call 5 minutes.


I don't get this at all. What is the advantage?

Aerobatics and local winch ops have the common feature that one
doesn't expect to be sharing airspace with other users. In this case,
it doesn't matter to others what you use for an altimeter setting.

When sharing airspace with others -- which is most of recreational and
virtually all of competition soaring -- it's stupid not to have
everyone on a common standard. This is just as true when local
soaring around a public use airport as it is for cross country.

-Evan Ludeman / T8

On Jan 29, 4:44*am, T8 wrote:
It is still nice to have QFE set for your
competition finish and I will re-set especially if control is giving it as
you call *5 minutes.

I don't get this at all. *What is the advantage?

Aerobatics and local winch ops have the common feature that one
doesn't expect to be sharing airspace with other users. *In this case,
it doesn't matter to others what you use for an altimeter setting.

When sharing airspace with others -- which is most of recreational and
virtually all of competition soaring -- it's stupid not to have
everyone on a common standard. *This is just as true when local
soaring around a public use airport as it is for cross country.

-Evan Ludeman / T8

Now that the webinar is over. What is Tom's take on all this?
Tom, do you set to zero, or actual field elevation prior to launch?
And why continue the discussion with the FAA.
91.121 is the rule with no exceptions.
We should be teaching our students the proper way and get them
ingrained to do the mental math to compute AGL from an MSL altimeter
from day one!

T