Altimeter Setting

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.

"Yeah, but as for 91.121 you're not maintaining any particular
cruising
altitude or flight level when operating a glider. "


The FAA legal department told me they recognize the problem /
confusion with the English language usage used in the regulation.
Gliders do not "cruise." However, the intent of the rule is clear.
Glider pilots must be aware of airspace altitude restrictions
including aircraft cruising.

Recognized exceptions to setting the altimeter to MSL include crop
dusting and aerobatics.

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.

It will only take a very few of these encounters for gliders to be
required to have ADS-B transponders and perhaps be banned from certain
airspace near airports where larger aircraft fly altogether.

A new, highly accurate GPS satellite was launched yesterday. First of
a series leading up to the new transponder technology.

Tom Knauff

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, 6:36*am, Tom wrote:
"Yeah, but as for 91.121 you're not maintaining any particular
cruising
altitude or flight level when operating a glider. "

The FAA legal department told me they recognize the problem /
confusion with the English language usage used in the regulation.
Gliders do not "cruise." However, the intent of the rule is clear.
Glider pilots must be aware of airspace altitude restrictions
including aircraft cruising.

Recognized exceptions to setting the altimeter to MSL include crop
dusting and aerobatics.

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.

It will only take *a very few of these encounters for gliders to be
required to have ADS-B transponders and perhaps be banned from certain
airspace near airports where larger aircraft fly altogether.

A new, highly accurate GPS satellite was launched yesterday. First of
a series leading up to the new transponder technology.

Tom Knauff


Thanks for the clarification of the FAA perspective on this. That and
just commons sense also says teach and use QNH, do instructors want
glider pilots to talk to other traffic?, to ATC when needed?, if there
is no other traffic or ATC locally, do instructors want pilots to have
the good foundation to do so when it would add to saftey? Do they want
pilots fixated on altimeter measurements in off-field landings (which
setting QFE may encourage), etc. Do they want new student pilots to be
heading towards flying XC or wasting time flying patterns? Start them
doing things properly and it won't need to be undone if those students
happen to blunder their way to a successful transition to XC flying.
It maybe is more a worry if there are DPE's out there that let a
student pass a check ride with QFE set. I know at some locations the
difference may not be noticed.

---

On the near miss, was they point that the glider pilot should have
been talking to ATC, and that QNH vs. QFE settings there a factor? Or
was the point something else?

If it was in an area of high density airline traffic then a good
option for the glider pilot would be to install a transponder.
Different ATC facilities are also very accommodating in terms of
working with gliders on flight following or similar procedures, most
would much rather hear from us than not.

Unfortunately Tom's post seems to confuse ADS-B and transponders.
Since we are facing lots of confusion sorting our the benefits,
issues, etc. with ADS-B I really want to avoid confusion on basic
points like this.

The new GPS satellite really has nothing directly to do with ADS-B,
although it will help improve GPS overall.

ADS-B is not a transponder. If using UATs there is no transponder
involved. If using 1090ES then the transponder is transmitting ADS-B
data but that's kind of an entirely separate function from it's role
as a transponder. Transponder literally means something that replies
to an interrogation. ADS-B is the reverse, the "A" means "automatic"
i.e. no interrogation. So strictly there is no such thing as an "ADS-B
transponder".

To my previous post in a separate thread on ADS-B, if the issue is
gliders flying in areas of high airline or fast jet traffic, that
traffic is very well equipped with TCAS II which can issue a
resolution advisory (RA) to help avoid the glider. TCAS II only can do
so if the glider is equipped with a Mode C or Mode S transponder. TCAS
cannot issue an RA against an ADS-B UAT equipped glider that does not
also have a transponder. Those airliners and fast jets may or may not
be able to display ADS-B UAT equipped glider traffic depending on
whether they have ADS-B CDTI capabilities on their traffic displays
(and again CDTI does not issue an RA, that's TCAS-II's jobs). There is
no requirement for anybody to equip with CDTI. As the FAA rolls out
ADS-B GBTs (Ground Based Transceivers==ground stations) ATC will see
ADS-B UAT traffic on their traffic displays. It is quite likely that
ATC radar will not see gliders today that are not transponder
equipped, and the GBTs will at least provide visibility of a UAT
equipped glider to ATC (and over a much larger airspace volume than
conventional SSR coverage). But without a transponder that last
fallback of TCAS-II won't work without transponders.

BTW I hope the ridge-running folks out there are trying to look at the
GBT coverage in areas they fly. That will give a good idea of the use
of ADS-B as a SAR/last know position tool. The other issue is going to
be a mixed environment of 1090ES and UAT devices on the ridges,
outside of GBT coverage to provide ADS-R (relay services) -- (e.g. at
points down low on a ridge) a Mode S transponder transmitting ADS-B
over 1090ES will not be seen by a UTA receiver and visa versa. The
only real solution I see there is dual-link receivers, luckily this is
not something terribly difficult, most of the work to do a UAT or
1090ES receiver is common, its just requires a bit more work, and
cost, to put both in one box.


Darryl

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

We can't set to "Zero" our MSL on the ground is higher than the altimeter
can adjust.

We train our students to "enter the downwind between 3800-3600 MSL (800-1000
AGL), then forget the altimeter. LOOK OUTSIDE

We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.

If the tow pilot cannot do mental math to call down the release height..
6400 release minus 2800 field elevation = 3.6 for the radio call then
perhaps the tow pilot is over tasked and should not be flying?
We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.

If we were to try to use zero... then how would our students or other
"trained pilots" know when they are bumping their heads on the Class B above
us defined by MSL, or if a transient traffic calls at a set altitude.. they
they may be at the same altitude and not 1000ft different?

We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.

A visiting pilot trying to set zero, will not be approved for local solo
flights until he can show proficiency at FAR required operations (91.121)

We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.


"kirk.stant" wrote in message
...
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

(snip)
We can't set to "Zero" our MSL on the ground is higher than the altimeter
can adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter can
adjust.

Uhh, nice try- but you were assigned 25 standards to write about not
being able to set "Zero" on your altimeter at your MSL on the ground -
and you only turned in five. Unacceptable. For that, you owe 25 more,
plus 25 additional standards about skimping on your assigned
standards.

When those are done and you've calmed down we can talk about when you
get to start soaring again, but for now your grounded mister. à²*_à²*

-Paul

ROFLMAO...


"sisu1a" wrote in message
...
(snip)
We can't set to "Zero" our MSL on the ground is higher than the altimeter
can adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter
can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter
can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter
can
adjust.
(snip)
We cannot set "Zero", our MSL on the ground is higher than the altimeter
can
adjust.

Uhh, nice try- but you were assigned 25 standards to write about not
being able to set "Zero" on your altimeter at your MSL on the ground -
and you only turned in five. Unacceptable. For that, you owe 25 more,
plus 25 additional standards about skimping on your assigned
standards.

When those are done and you've calmed down we can talk about when you
get to start soaring again, but for now your grounded mister. à²*_à²*

-Paul

II'm sure someone already pointed this out but in the US, I really
don't have a choice...

Sec. 91.121

Altimeter settings.

(a) Each person operating an aircraft shall maintain the cruising
altitude or flight level of that aircraft, as the case may be, by
reference to an altimeter that is set, when operating--
(1) Below 18,000 feet MSL, to--
(i) The current reported altimeter setting of a station along the
route and within 100 nautical miles of the aircraft;
(ii) If there is no station within the area prescribed in paragraph (a)
(1)(i) of this section, the current reported altimeter setting of an
appropriate available station; or
(iii) In the case of an aircraft not equipped with a radio, the
elevation of the departure airport or an appropriate altimeter setting
available before departure; or
(2) At or above 18,000 feet MSL, to 29.92'' Hg.