Altimeter Setting

On May 31, 11:06*pm, ContestID67 wrote:
Rolf,


So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. Seems like learning and adhering to the FARs is a
critical part of soaring. If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

On Jun 2, 10:43*am, Rob wrote:
On May 31, 11:06*pm, ContestID67 wrote:

Rolf,

So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. *Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. *Seems like learning and adhering to the FARs is a
critical part of soaring. *If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

That maybe you have the wrong instructor.
UH

On Jun 2, 10:57*am, wrote:
On Jun 2, 10:43*am, Rob wrote:

On May 31, 11:06*pm, ContestID67 wrote:

Rolf,

So about 5 years ago my Club's flight chair said that flying AGL was
wrong, dangerous and (if I am not mistaken) illegal. *

The "legal" issue is a slippery slope. *Newbies to the sport (and I
still consider myself one) may take everything their instructor says
as the bible. *Seems like learning and adhering to the FARs is a
critical part of soaring. *If we're taught to break certain FARs from
the get go, what is the lesson there?

Rob

That maybe you have the wrong instructor.
UH

Perhaps, but the student is the wrong person to judge the
professionalism of the instructor. I seem to recall that as one
of the 1 hour sessions in my last CFI clinic, after all. All of us
instructors do have the duty to be professional about what we're
teaching.

When I started flying many years ago the glider operation used
QFE since we were only doing local flying. It was pointed out at some
point that we would have to convert to doing it the proper way, but
that
pattern ops were easier to teach that way. Later I moved to
a club environment that pretty much used QNH. I took my flight test
there and it was pointed out that you had to switch over to QNH
before you could take the test. After that, I moved to yet another
club that was mostly using QFE, but after several years Tom came to
visit, and we've used QNH since then. I have to say that it never
really
bothered me as to which setting was in use.

Whenever going cross country, of course, I have always used QNH and,
for that matter,
I never look at my altimeter once I'm established on downwind, anyway.
At the very first place we used Tom's landing checklist that ended
with
"ignore the altimeter", and that's stuck with me all along. I fly
at least 80 flights a year as a primary instructor, and truthfully I
can't tell
you at what altitude we turn base or final. I judge those turns
entirely
by angle.

-- Matt

On Jun 2, 10:27*pm, "
wrote:
Then how about "metric" altimiters? *300 meters per revolution

I've never seen that, but I've flown a few gliders with altimeters
where one revolution is 3000 ft -- presumably designed to be 1000m
and tweaked by 10%.


I really can't see that it's important what you set before takeoff in
a glider. QFE is as good as anything if you're not going to talk to
anyone, and all you usually care about is which way the needle is
rotating. If you *do* have to talk to someone then you should be
listening on the radio to set your altimeter to the appropriate and
latest QNH for the area.

On Jun 2, 11:41*am, Bruce Hoult wrote:
On Jun 2, 10:27*pm, "

wrote:
Then how about "metric" altimiters? *300 meters per revolution

I've never seen that, but I've flown a few gliders with altimeters
where one revolution is 3000 ft *-- presumably designed to be 1000m
and tweaked by 10%.

I really can't see that it's important what you set before takeoff in
a glider. QFE is as good as anything if you're not going to talk to
anyone, and all you usually care about is which way the needle is
rotating. *If you *do* have to talk to someone then you should be
listening on the radio to set your altimeter to the appropriate and
latest QNH for the area.

But it's so easy to do this correctly (QNH)... all the time. It costs
nothing.

-T8

On Jun 2, 6:39*am, "
wrote:
On Jun 2, 7:16*am, Cats wrote:

....Also MSL is not the
"datum" used in collision aviodance.

Cookie

Uh, wrong. When you report your altitude over the radio, you are
going to read it off the altimeter, and if you are below 18,000ft (in
the US) it should be set to QFE for the closest reporting point.

So when someone calls out that he is "Eastbound over Littletown at
7300ft" on a hazy afternoon, and you are westbound over Littletown,
staring into the sun, at 7400ft, you had better hope he is using the
correct altimeter setting! Cuz that's how you are going to check to
see if you have altitude deconfliction (since I doubt you have TCAS in
your glider).

You are correct that transponders use pressure altitude when
reporting, but that is a different issue - you don't normally use raw
Mode C altitude data in the cockpit for altitude deconfliction - and
ATC applies a correction when reporting traffic altitude over the
radio.

My .02$: QFE can be useful for low altitude aerobatics - for an
airshow pilot who performs at a lot of different locations. That's
about it, since the advent of radio altimeters and GPS. Otherwise,
QNH is what should be used (and it's arguably required by the FARs),
from the very beginning. I don't want to share airspace with someone
who can't do the math and needs the altimeter to know when to turn
Base and Final! (Hint - if you are really math-in-the-cockpit
challenged, write the darn pattern altitude on the back of your
hand!).

Kirk
66

On Jun 2, 2:36*pm, Tom wrote:
snip

Yesterday, there was a very close near-miss with a glider and
commercial jet descending for a landing. The club where the glider
flies commonly uses and teaches using AGL altimeter settings.
snip

And did the glider's altimeter setting have anything to do with the
near-miss?

On Jun 2, 6:36*am, Tom wrote:

required to have ADS-B transponders

Unless I completely misunderstood the concept ADS-B (OUT) is not a
transponder system. It will transmit without interrogation.

Andy

On Jun 2, 11:10*am, "kirk.stant" wrote:
On Jun 2, 6:39*am, "
wrote: On Jun 2, 7:16*am, Cats wrote:

...Also MSL is not the

"datum" used in collision aviodance.
Cookie

Uh, wrong. *When you report your altitude over the radio, you are
going to read it off the altimeter, and if you are below 18,000ft (in
the US) it should be set to QFE for the closest reporting point.

Doh... obviously, I meant "QNH" (set to read MSL) not QFE (set to read
height above selected airfield).

Later reference to QFE is correct.

Everyone sufficiently confused now?

Now back to your regular program....

Kirk
66

On Jun 2, 8:04*am, 150flivver wrote:
On Jun 2, 12:38*am, (Alan) wrote:





In article 150flivver writes:

On May 31, 10:14=A0pm, GM wrote:

Rolf, if memory serves me right, the FARs are clear about it: setting
to MSL is required.

I don't recall any regulation requiring the altimeter to be set to QNH
unless the particular operation requires it (eg. an instrument
approach).

* 14 CFR 91.121 * (aka FAR 91.121)

* For extra credit, note 91.121(a)(1)(i) which says you must use the setting
from the local radio source in preference to setting to the field elevation.
As was pointed out in this group a couple years ago, the examiner in the back
seat knows that regulation.

* * * * Alan

Yeah, but as for 91.121 you're not maintaining any particular cruising
altitude or flight level when operating a glider. *I certainly agree
that cross country gliders should be operating off QNH but if you're
flying *locally, you should have the option of setting QFE. *I fly a
towplane and use QFE 99% of the time--any position calls I make I
convert to MSL (I have a table to reference on my legboard). *If I
have to go and retrieve a landout, I'll use QNH.- Hide quoted text -

- Show quoted text -

Interesting. I also fly a towplane for a club and use QNH exclusively
- so when I call the glider release, it's MSL and doesn't need any
conversion (and associated potential for mistake). That call is a
safety-of-flight issue, IMHO - and not only for local club traffic,
but for any other aircraft passing by - and much more important than
reporting the tow height to the ground for billing purposes (which, in
our club, is not a tow pilot responsibility anyway - the member logs
it after the flight or gets charged a flat 3k ft tow...). As chief
tow pilot I don't want my tow pilots doing anything during their tow
flight that takes them away from clearing their flight path,
especially with lots of gliders milling around!

Kirk
66