Altimeter Question

Mark Hansen wrote in
news:Nr2dnRgnVOuoTpXVnZ2dnUVZ_t7inZ2d@surewest:

On 04/18/08 08:38, Michael Ash wrote:
In rec.aviation.student Andy Hawkins wrote:
The PAN actually sounds to me like a good idea, but as I always say
I'm still a lowly stude! Being able to differentiate between a
Mayday (basically aircraft in imminent danger) and PAN (something
that needs priority but nothing that will endanger the aircraft in
short order) seems like a good idea to me.

Given the rarity of emergency calls, it seems like the important
thing is to make the emergency known in a simple and easy fashion
first, then work out the details later on as they're needed. The
distinction is useful, but I think that it's not worth putting extra
workload on the pilot to figure out just what degree his emergency is
in his moment of crisis.


If the pilot is in a moment of crisis, then an emergency should be
declared. PAN is used when it is not at that level.



That's th epoint, Pan is no longer in the common lexicon. The guy I
quoted earlier risked his passeneger's life being a pedantic ****.


Bertie

Stealth Pilot wrote in
:

On Thu, 17 Apr 2008 14:54:53 +0000 (UTC), Bertie the Bunyip
wrote:

terry wrote in news:179c2f21-99ad-4415-a9b2-
:

On Apr 18, 12:07*am, Bertie the Bunyip wrote:
terry wrote in news:234756e2-a583-4cbc-
8f42-
:

I am confused by this practice commercial nav question. ( at
least
I
am confused by the answer in the book which was b. but I think
both
a
and c are correct), but I appreciate some other opinions.

Day 1 Altimeter reads elevation of 1390 feet with 1013 HPa set on
subscale
* * * * *( thats equivalent to 29.92 inches of Hg for the US f
olks)
Day 2 Altimeter reads elevation of 1000 feet
Assuming the altimeter subscale was not changed between day 1 and
day
2 it could be said that

a. The QNH is higher on day 2
b. The QNH is lower on day 2
c. The pressure altitude at the airport is lower on day 2
d. *The atmospheric pressure at the aerodrome has not changed.

It's A. It could also be C if the airfield has a serious subsidance
problem.

you are really confusing me now Bertie, I got learned that the
pressure ht was wot your altimeter reads when you have 1013.2 in the
window ( or 29.92 for you ...or maybe not cos everyone knows bunyips
are aussies ) 1000 is lower than 1390 therefore pressure altitude
is
lower on day 2.. surely!.


Yer right, of course, I just couldn't resist the joke! There's a name
for that, if I'm not mistaken, and it's QNE. But theyre going for A,
I'm
pretty sure and made an error in what thye were trying to say in C.
I'm
bi-barometric, BTW.

Bertie

bi-barometric? is that as bad as being queer :-)


Depends, I beleive a queer in your neck of the woods is someone who
prefers women to beer.


Bertie

terry wrote in news:ea7c4c43-ffdf-4802-825b-
:

On Apr 18, 9:05Â*am, Bertie the Bunyip wrote:
terry wrote in news:375462b0-66e7-4ed0-b45d-
:







On Apr 18, 7:10�am, Stefan wrote:
WingFlaps schrieb:

Perhap we are at crossed purposes but an ARFOR does not refer to
an
airfield -that's a METAR and not all fields issue them. So in
this
case how can QNH give field elevation unless it's an ISA day?

Again: QNH gives *by definition* the field elevation. If an ARFOR
gives
you a QNH, then it is related to one well defined spot on the
surface.

As I understand it ( In Australia) the QNH in an ARFOR must be
within
5 mbar of the "real QNH" Â*- ie what gives you field elevation for
a
ny
place within that area. otherwise the area will be broken up into
sub
areas and no 2 adjacant sub areas must differ by more than 5 mbar.
That way the errors which Wing flap alludes to, and must certainly
exist in non ISA atmosphere, would result in errors of no more than
150 feet between aircraft using either the correct AFROR QNH or the
airfield set QNH

Yipes! Are you studying to be an astronaut?

Are there any openings?


Sure! Lots of applicants though.

Bertie

Stefan wrote in news:ac07e$4808485c$54487328
:

Bertie the Bunyip schrieb:

Again: QNH gives *by definition* the field elevation.

Only at the airport ref point, so, no, it doesn't.

Fascinating: You, who *never* ever have trimmed a post before you
answered, are doing this for the first time! A miracle? A convert?
No, a closer look reveals your reason: The untrimmed text was

Again: QNH gives *by definition* the field elevation. If an ARFOR
gives
you a QNH, then it is related to one well defined spot on the
surface.

Which is exactly what you wrote in your answer. So without trimming,
you
couldn't have written "no". You're such an asshole.



nice try.

You wuz wrong, cheese nazi.

Bertie

WingFlaps wrote in
:

On Apr 18, 11:04*am, Bertie the Bunyip wrote:
Stefan wrote in
news:c9458$4807bcae$54487328$455
1
@news.hispeed.ch:

WingFlaps schrieb:

Perhap we are at crossed purposes but an ARFOR does not refer to
an airfield -that's a METAR and not all fields issue them. So in
this case how can QNH give field elevation unless it's an ISA day?

Again: QNH gives *by definition* the field elevation.

Only at the airport ref point, so, no, it doesn't.

He'll get it in the end... high to low look out below! I'll guess he's
not flown Xcountry to non ATIS fields?


I doubt he flies at all.


Bertie

Stefan wrote in
:

WingFlaps schrieb:

BINGO! That's right, setting QNH on an altimeter DOES NOT does give
field elevation UNLESS it's issued for that field :-)

Which has been pretty obvious, hasn't it? But I forgot that this is
Usenet.



Oowww!


Backpedaling and obfuscating!




How predictable.


Bertie

Stefan wrote in
:

WingFlaps schrieb:
On Apr 18, 6:56 pm, Stefan wrote:
WingFlaps schrieb:

BINGO! That's right, setting QNH on an altimeter DOES NOT does give
field elevation UNLESS it's issued for that field :-)
Which has been pretty obvious, hasn't it? But I forgot that this is
Usenet.

Nope it's not Usenet, it comes back to correcting the erroneous idea
that setting QNH on an altimeter makes it faithfully report altitude.

Which nobody claimed.




Yes, you did.

Shoudlnt; you be counting some gold teeth or something?

Bertie

Bertie the Bunyip wrote:
What happens is that the transition level is localised. they're usually
between 3,000 and 5,000 above the local terrain, though that depends on
airspace divisions around the area and local state views and traditions.
Usually you can expect to transition around 4-5 thou above the airport
going up. In mountainous areas, minimu flight levels are dictated by the
QNH and temperature. The US is the only country I know of that has a
nationwide transition as high as 180.


Understood about the flight levels, but how does one set QFE on an
altimeter on a high altitude airport? Most altimeters I've seen don't have a
sufficient range in the Kollsman window to set anything above 3,000 ft. or so.


John Galban=====N4BQ (PA28-180)

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200804/1

"JGalban via AviationKB.com" u32749@uwe wrote in
news:82df7b9654bd5@uwe:

Bertie the Bunyip wrote:
What happens is that the transition level is localised. they're
usually between 3,000 and 5,000 above the local terrain, though that
depends on airspace divisions around the area and local state views
and traditions. Usually you can expect to transition around 4-5 thou
above the airport going up. In mountainous areas, minimu flight levels
are dictated by the QNH and temperature. The US is the only country I
know of that has a nationwide transition as high as 180.


Understood about the flight levels, but how does one set QFE on an
altimeter on a high altitude airport? Most altimeters I've seen don't
have a sufficient range in the Kollsman window to set anything above
3,000 ft. or so.



Ah, right. I see what you mean now. I have a friend who operates for a
company that uses QFE and he says you nearly need a crank handle on it
for some high alt airfields! I don't know if he has a different sort of
altimeter in the 767 he flies, but I ran out of nubers at 1050 when I
was in helsinki a while back and it was at 1052. Maybe it's a special
order. he was talking about a plce that was about 6,000 feet up.
I used to work for a place that used QFE for approach and landing and I
found it a major PITA.
We never went anywhere over 2,000 feet, though.


Bertie

If the pilot is in a moment of crisis, then an emergency should be declared.
PAN is used when it is not at that level.

The AIM goes into this in detail. MAYDAY is for an aircraft in distress,
while PAN-PAN is for an urgency condition. Both are emergencies:

6-1-2 a. An emergency can be either a distress or urgency condition as defined
in the Pilot/Controller Glossary. Pilots do not hesitate to declare an
emergency when they are faced with distress conditions such as fire,
mechanical failure, or structural damage. However, some are reluctant to
report an urgency condition when they encounter situations which may not be
immediately perilous, but are potentially catastrophic. An aircraft is in at
least an urgency condition the moment the pilot becomes doubtful about
position, fuel endurance, weather, or any other condition that could adversely
affect flight safety. This is the time to ask for help, not after the
situation has developed into a distress condition.

6-3-1 c. The initial communication, and if considered necessary, any
subsequent transmissions by an aircraft in distress should begin with the
signal MAYDAY, preferably repeated three times. The signal PAN-PAN should be
used in the same manner for an urgency condition.

http://www.faa.gov/airports_airtraff...6/aim0601.html