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altimeter

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kerrjohna(at)comcast.net
Guest

Posted: Fri May 05, 2006 7:31 am Post subject: altimeter

Okay guys, I have aquired an older altimeter with Kolzman window, and this is what has me wondering, when the barometer is adjusted there is a bug that moves around the perimeter of the altimeter.  The bug moves faster than either of the needles.  What purpose does the bug serve?



John

<html><body>

<DIV>Okay guys, I have aquired an older altimeter with Kolzman window, and this is what has me wondering, when the barometer is adjusted there is a bug that moves around the perimeter of the altimeter.&nbsp; The bug moves faster than either of the needles.&nbsp; What purpose does the bug serve?</DIV>

<DIV>&nbsp;</DIV>

<DIV>John</DIV></body></html>

bmwebb(at)cox.net
Guest

Posted: Fri May 05, 2006 1:51 pm Post subject: altimeter

Dunno. Possibly pressure altitude?



Bradley



--

smokey_bear_40220(at)yaho
Guest

Posted: Fri May 05, 2006 9:07 pm Post subject: altimeter

It is a reminder bug for the minimums on IFR

approachs.  I use it every time at work.



Kurt S.



--- Bradley M Webb <bmwebb(at)cox.net> wrote:



[quote] Dunno. Possibly pressure altitude?

 

 Bradley

 

 --

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Fri May 05, 2006 10:20 pm Post subject: altimeter

On May 6, 2006, at 7:03 AM, kurt schrader wrote:



 	  Quote: 	
		   It is a reminder bug for the minimums on IFR approachs.  I use it 

 every time at work.


	


My licence being VFR only, but for the sake of my general interest for 

aviation, please could you, please, explain "minimum IFR approach," 

Kurt?

Since the bug moves are one adjusts the pressure, I guess this is only 

valid under transition altitude, when on QNH setting. Does the bug 

shows transition level (a variable) ? But that changes from AD to AD, 

doesn't it? I am sure I am completely on the wrong track and I look 

forward to your answer.

PS: Springtime has finally come to Norway: 18 C and sunshine. Got my 

oil cooler re-installed on the Kitfox and I am ready for a nice flying 

summer!



Cheers,

Michel



do not archive

_________________
Kitfox 3 - Jabiru 2200

smokey_bear_40220(at)yaho
Guest

Posted: Fri May 05, 2006 11:47 pm Post subject: altimeter

Great question Michel,

And a serious one my company and others are struggling

with right now.

When you fly an IFR approach, you have a certain

descent point at which you can go no lower until you

see something.  There is a long list of what you have

to be able to see first before you descend to land,

but basically enough to land on the runway and not

highway 65 or the baskin robbins by mistake, etc.

On nonprecesion approaches you descend to an altitude,

then fly to a point and take a missed approach, if you

don't see enough to land.

On a precision approach you descend to an altitude on

a glidepath and then must do the missed approach

immediately at that altitude, if you don't see enough

to land.

In either case you set that bug to the altitude for

the approach and stop descent there - no lower unless

you can land.

The problem is that there are different transition

altitudes, inches of mercury and millibar settings,

QNE, QFE and QNH settings and different missed

approach altitudes for every runway.  One missed

setting and you get "skidmarks in the sky" or a

surprise landing where you shouldn't.

And for some approaches you don't look at that

altimeter, but at the radio altimeter instead.

I have missed altimeter settings 3 times since

starting flying in 1966 with maybe 14,000 hrs since

then.  Two of them were this year!

In reporting this I learned that it is a major trend

right now for pilots.  We have no transition altitude

bug, just the missed approach bug we are talking about

here.  It is mostly the transition altitude that is

the current problem and the reason "why now" and what

to do about it are in discussion.

Add in the different altitudes and altimeter settings,

a Costa Rican pilot with a Boston accent, an

Equidorian controller trying to speak English,

mountains, weather, other pilots trying to speak

english, spanish or portugese, an approach checklist

you do at 25,000 feet that has the altimeter setting

on it, but you don't actually change the altimeter

until 6,000 feet, today only, because of the weather,

and you go trouble.

If using QFE, you land at zero.  Otherwise you land at

the airport elevation above sea level.  That bug has

to be set to, say 200 feet if landing at zero, or 200

feet above the airport elevation, which may be 8370

feet, like in Bogata Columbia.  And you don't change

the other bug, the altimeter setting, until 18,000',

or 6000', or 3000' or whatever the contoller or ATIS

says happens to be right day.

Basically this is an accident waiting to happen.  You

have to make an important change out of sequence in

the checklist, at a different point each day, during

the busiest part of the flight, without a reminder.

I have gone to sticky note pads on my altimeter as a

fix for the present.

One simple gauge and we have to make it so complex to

apply!  And in the computer age.

We suggested the computer should remind us.  It has

the info built in for all airports, just not used. 

Another thing would be for us all to be consistant as

to when to change and milibars or hectopascals.  Not

happening even if lives depend on it.

So one knob changes the altimeter to current pressure,

the other remindes you of how low you can go, and the

third is missing.

Kurt S.

--- Michel Verheughe <michel(at)online.no> wrote:

 	  Quote: 	
		   On May 6, 2006, at 7:03 AM, kurt schrader wrote:

 > It is a reminder bug for the minimums on IFR

 approachs.  I use it 

 > every time at work.

 My licence being VFR only, but for the sake of my

 general interest for 

 aviation, please could you, please, explain "minimum

 IFR approach," 

 Kurt?

 Since the bug moves are one adjusts the pressure, I

 guess this is only 

 valid under transition altitude, when on QNH

 setting. Does the bug 

 shows transition level (a variable) ? But that

 changes from AD to AD, 

 doesn't it? I am sure I am completely on the wrong

 track and I look forward to your answer.

 	  Quote: 	
		   PS: Springtime has finally come to Norway: 18 C and

 sunshine. Got my oil cooler re-installed on the

 Kitfox and I am ready for a nice flying summer!

 Cheers,

 Michel

 do not archive

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kerrjohna(at)comcast.net
Guest

Posted: Sat May 06, 2006 6:24 am Post subject: altimeter

Kurt, Thanks, I think. But it can not be adjusted independently of the the altimeter setting.

John

-------------- Original message -------------- 

From: kurt schrader <smokey_bear_40220(at)yahoo.com> 

[quote] 

 It is a reminder bug for the minimums on IFR 

 approachs. I use it every time at work. 

 Kurt S. 

 --- Bradley M Webb wrote: 

 > Dunno. Possibly pressure altitude? 

 > 

 > Bradley 

 > 

 > --

bmwebb(at)cox.net
Guest

Posted: Sat May 06, 2006 8:26 am Post subject: altimeter

John,

Put your baro setting at 29.92. Now read the altitude at the needles. Now

set it to local QNH. Read what the bug says. I'd bet they're the same

reading.



Bradley



--

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Sat May 06, 2006 11:33 am Post subject: altimeter

On May 6, 2006, at 9:42 AM, kurt schrader wrote:



 	  Quote: 	
		   That bug has to be set to, say 200 feet if landing at zero, or 200

 feet above the airport elevation,


	


Thanks Kurt, I understand now the use of your "bug setting" in 

consideration to minima. But John means that his instrument has only 

one knob, the one for the "Q" setting and the same knob turns that bug 

too.

Talking about "Qs" there is also QFF, which is only relevant to 

meteorology.



 	  Quote: 	
		   Another thing would be for us all to be consistant as

 to when to change and milibars or hectopascals.


	


As a life-time pilot, are you ready to make the jump, Kurt? Mind you, 

officially, the US has gone metric. Time Magazine, the trend setter, 

writes in meters for some years now. But I guess old habits are 

difficult to quit. Nothing is better with the hectopascals, it's just 

that we must standardise on something and it looks like the French with 

their meter have won the war of the measures. Mind you, the lost it a 

century ago, with Greenwich as the prime meridian, but they got a half 

victory recently when they got GMT renamed UTC. Ah, the damn froggies!  

Zut! ze damn roastbeef, remember Joan of Arc!  Sorry guys, I have 

been at sea with Brits and French on the same boat. I am still laughing 

at it! 



Cheers,

Michel



do not archive

_________________
Kitfox 3 - Jabiru 2200

smokey_bear_40220(at)yaho
Guest

Posted: Sun May 07, 2006 8:35 am Post subject: altimeter

Hi Michel,

Flying above 10,000 feet opened pilots to new

problems.  Lack of oxygen was one, but there was

another....

There are "old wives' tales" of early high flying

planes descending to 10,000 feet at night and landing

in the ocean.  While that may not be true, it isn't

hard to misread an altimeter by 10-20-30,000 feet, if

all you have are the 2 hands to look at.  There were

very likely times when pilots found themselves much

lower than they thought from misreading altimeters,

especially in the military on diving bomb runs.  Those

hands spin pretty fast going verticle!  I know.  I

went 1000 feet low once myself and the pullout was

high G!

It is worse since our military maps are metric and the

altimeters are in feet.  Easy to hit a 400 meter hill

when descending to 1000 feet.

Some altimeters added a third short hand, or a bug to

show 10's of thousands.  The one with a bug might be

what John has.  I haven't seen one in quite a while. 

If you climb to 10,000 and the bugs moves to the 1, or

you climb to 5,000 and the bug moves 1/2 way to the

one, than that is it.

Newer altimeters have 2 hands and a drum roll of

numbers like an odometer so you can read both.  You

still have to avoid reporting FL 340 when your

altimeter says 34,984 and you should say FL 350.  That

34 really stands out on the drum roll because it is in

larger numbers.

Why aren't you at FL 350?  With 3 altimeters in the

cockpit, there will be disagreement up high and exact

altitudes are - well, the captain is always right!

I have also seen an altimeter with only one hand.  It

went up to 25,000 I think.  Maybe 15,000?  The face

was very busy or compressed with all the numbers and

it would be hard to quickly read altitudes closely.  I

wonder if they are used for baloons?  You have plenty

of time to read fine details on an altimeter in one of

those.

Heck-with-pascals?  Time Mag a trend setter?  Michel! 

Actually, as you know, companies like Ford had to

switch to metric to sell out of the U.S. long ago. 

This is the British revenge on us.  When everyone else

can relate weight to volume to distance, we are still

stuck with totally untrelated measures that make no

sense, except to the Crown's body measurements.  Like

with the altimeter, in metric you still have to watch

those zero's.  But metric is a much easier system to

see matematical relationships with.  We should have

switched before the Brits, but we were isolationists

back then.

Reminds me of the Romans.  Great engineers, but you

can't do "pie' in roman numerals.  They used Greek

matamaticians to do their calculations to make all

those arches!  How do you do fractions in Roman

numerals anyway?  Decimals?

Unfortunately hectopascals are not as fine a measure

as inches of mercury, so altimeter settings are not as

accurate with them.

But we sure showed the British by driving on the other

side of the street!  Now when we drive overseas, you

can tell right away.  The windshield wippers go on

whenever we make a left turn because the wipper switch

is on the other side from the signal switch.  (It

doesn't happen on right turns because the wipper

switch won't go down.)  And we look to the wrong side

when crossing the street.  And we see cars with only

passengers in them.....

So, yes, I am ready for a standard and metric makes

sense, mostly.  Heck-with-pascals!

Brits and French on the same boat!  Usually only

happened when one lost to the other.  Maybe that is

still the reason?    Who's boat was it and who was

captain?

Kurt S.

--- Michel Verheughe <michel(at)online.no> wrote:

 	  Quote: 	
		   On May 6, 2006, at 9:42 AM, kurt schrader wrote:

 	  Quote: 	
		   Thanks Kurt, I understand now the use of your "bug

 setting" in consideration to minima. But John means

 that his instrument has only one knob, the one for

 the "Q" setting and the same knob turns that bug 

 too.........

 > Another thing would be for us all to be consistant

 > as to when to change and milibars or hectopascals.

 As a life-time pilot, are you ready to make the

 jump, Kurt? Mind you, officially, the US has gone

 metric. Time Magazine, the trend setter, .......

 	  Quote: 	
		   ......the damn froggies!  

 Zut! ze damn roastbeef, remember Joan of Arc! 

 Sorry guys, I have been at sea with Brits and

 French on the same boat.  I am still laughing 

 at it! 

 Cheers,

 Michel

__________________________________________________

asq1(at)adelphia.net
Guest

Posted: Sun May 07, 2006 9:05 am Post subject: altimeter

Kurt ,

  Another good point for metrification. Remember,that is how we lost one of 

our Mars landers. One group was working in English measure,the other in 

Metric. Even the English don't use the "English " system any longer. Only 

countries in the known universe still using it ,I believe, are Liberia,Burma 

,and the USA. Wonder how many   people in the rest of the world want our 

oddball measured products.  Trade deficit? hmmmm

                                                    Larry

---

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Sun May 07, 2006 12:50 pm Post subject: altimeter

Hello Kurt,



On May 7, 2006, at 6:32 PM, kurt schrader wrote:

 	  Quote: 	
		   Some altimeters added a third short hand, or a bug to

 show 10's of thousands.


	


I understand, Kurt. Our Kitfoxes (at least, mine, with the original 

instruments) also has a "third handle" that moves as a disc, with the 

window showing the diagonal lines in the background, a line up and a 

small triangle, to indicate the thousands of feet. But John was talking 

of a "fast moving bug" as he adjusted the pressure knob. I guess we'll 

have to hear from him.



 	  Quote: 	
		   Heck-with-pascals?  Time Mag a trend setter?  Michel!  


	


I beg your pardon, Sire, but I owe most of my English from being 

subscribed for at least 20 years to this excellent magazine. They were 

the first to e.g. write Beijing instead of Peking, as the Chinese 

required. I once remember reading a reader's letter saying about this: 

In you article, you wrote that Mark Twain wrote: "I never read there 

letters." He surely didn't write that. To what the editor answered: 

Yes, indeed, he did!

Now that the best example of proof reading I know of: When quoting an 

author that makes a mistake, it is correctly "wrongly" written. That 

takes quite a professional team of proof readers, my friend! Remember 

that Time is used to teach English worldwide.



 	  Quote: 	
		   So, yes, I am ready for a standard and metric makes sense, mostly.  

 Heck-with-pascals!


	


Being myself a fan of binary notation and boolean logic, I must say the 

the division of the inch in 16th or 32th is quite interesting. I only 

wish the Sumerians had divided the circle not in 360 degrees (wrongly 

assumed as the daily sun's right ascension) but in 256. It would have 

made life so much easier for a lot of computer programmers. BTW, here 

is a good one: "There are 10 different kinds of people: Those who count 

binary and those who don't!"  (got it? 



 	  Quote: 	
		   Brits and French on the same boat!  Usually only happened when one 

 lost to the other.  Maybe that is

 still the reason?    Who's boat was it and who was captain?


	


Thank you for asking!  The captain was Norwegian, the deck hands 

were Spanish and the flag was from Singapore! Oh, did I mention that 

there was one Belgian too, on board? 



Cheers,

Michel



do not archive

_________________
Kitfox 3 - Jabiru 2200

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