What is it?

The altimeter in this illustration http://en.wikipedia.org/wiki/Altimeter is
almost identical to the one in our Archer. I've been puzzling over what
that little black and white hatched area is on the dial ever since I bought
into the plane. It doesn't rotate with the Kollsman window knob, although
perhaps it rotates with the thousands hand, since it appears in this
illustration to be exactly opposite the hand. Anyone know what it's used
for? Inquiring minds want to know.

--
Bob (Chief Pilot, White Knuckle Airways)

"Bob Chilcoat" wrote in message
...

The altimeter in this illustration http://en.wikipedia.org/wiki/Altimeter
is almost identical to the one in our Archer. I've been puzzling over
what that little black and white hatched area is on the dial ever since I
bought into the plane. It doesn't rotate with the Kollsman window knob,
although perhaps it rotates with the thousands hand, since it appears in
this illustration to be exactly opposite the hand. Anyone know what it's
used for? Inquiring minds want to know.


It does rotate, just rather slowly. It tells you when you're over 10,000
MSL.

Steven P. McNicoll wrote:



It does rotate, just rather slowly. It tells you when you're over 10,000
MSL.


Nope. The hatch marks are painted on the same face that the big numbers
are painted on. They are stationary. The disk that supports the 10,000
ft pointer, and has the letters ALT painted on it, has a "window" cut
out of it, that will slowly cover up the hatchings as elevation
increases. At 10,000 ft, about 75% of the hatch marks are obscured. I
think this is to aid in visually identifying that you have reached the
tens of thousands of ft. elevation.

Happy Flying!
Scott Skylane

"Scott Skylane" wrote in message
...

Nope. The hatch marks are painted on the same face that the big numbers
are painted on. They are stationary. The disk that supports the 10,000
ft pointer, and has the letters ALT painted on it, has a "window" cut out
of it, that will slowly cover up the hatchings as elevation increases. At
10,000 ft, about 75% of the hatch marks are obscured. I think this is to
aid in visually identifying that you have reached the tens of thousands of
ft. elevation.


Nope? You just said it tells you when you're over 10,000 MSL.

Steven P. McNicoll wrote:
"Scott Skylane" wrote in message
...
Nope. The hatch marks are painted on the same face that the big numbers
are painted on. They are stationary. The disk that supports the 10,000
ft pointer, and has the letters ALT painted on it, has a "window" cut out
of it, that will slowly cover up the hatchings as elevation increases. At
10,000 ft, about 75% of the hatch marks are obscured. I think this is to
aid in visually identifying that you have reached the tens of thousands of
ft. elevation.


Nope? You just said it tells you when you're over 10,000 MSL.


I think what he meant was, "it" (the stripped area) doesn't rotate, the
window you see it through rotates with the 10000's pointer.

Brad

I believe, but am not absolutely sure, that the aircraft in this picture is
at 10,100 feet. The hatched area disappears slowly as you descent below
10,000. At sea level it ought to be mostly gone.

Jim


"Bob Chilcoat" wrote in message
...
The altimeter in this illustration http://en.wikipedia.org/wiki/Altimeter
is almost identical to the one in our Archer. I've been puzzling over
what that little black and white hatched area is on the dial ever since I
bought into the plane. It doesn't rotate with the Kollsman window knob,
although perhaps it rotates with the thousands hand, since it appears in
this illustration to be exactly opposite the hand. Anyone know what it's
used for? Inquiring minds want to know.

--
Bob (Chief Pilot, White Knuckle Airways)

RST Engineering wrote:

I believe, but am not absolutely sure, that the aircraft in this picture is
at 10,100 feet. The hatched area disappears slowly as you descent below
10,000. At sea level it ought to be mostly gone.

Just the opposite, Jim. The pictured altimeter is near sea level. At
10,000 ft, the hatched area is mostly obscured.

Happy Flying!
Scott Skylane

Does POH Ch 9 say anything about it?


Bob Chilcoat wrote:
The altimeter in this illustration http://en.wikipedia.org/wiki/Altimeter is
almost identical to the one in our Archer. I've been puzzling over what
that little black and white hatched area is on the dial ever since I bought
into the plane. It doesn't rotate with the Kollsman window knob, although
perhaps it rotates with the thousands hand, since it appears in this
illustration to be exactly opposite the hand. Anyone know what it's used
for? Inquiring minds want to know.

It warns you when you're low enough to hit ground. Useful in
instrument flying.

According to FAA's "Instrument Flying Handbook":

"Below 10,000 feet, a striped segment is visible. Above this altitude,
a mask begins to cover it, and above 15,000 feet, all of the stripes
are covered."

- Tom

On Sat, 22 Jul 2006 16:43:49 -0400, "Bob Chilcoat"
wrote:

The altimeter in this illustration http://en.wikipedia.org/wiki/Altimeter is
almost identical to the one in our Archer. I've been puzzling over what
that little black and white hatched area is on the dial ever since I bought
into the plane. It doesn't rotate with the Kollsman window knob, although
perhaps it rotates with the thousands hand, since it appears in this
illustration to be exactly opposite the hand. Anyone know what it's used
for? Inquiring minds want to know.