Altimeter off

How can you adjust an altimeter if the pressure isn't correct in the
window for the altitude? I started talking to my examiner about it on
the checkride and he said that a lot of people adjust it themselves
(not an avionics shop, etc), and he said you take the front off (I
think) and theres a screw to adjust it? The plane would be used for
VFR only...

Is there an adjustment that can be made to the encoder as well if it's
off?

Not legal, you'll screw it up. Even an A&P is not allowed
to "adjust" instruments internally. You should take it to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.



"kevmor" wrote in message
ups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my examiner
about it on
| the checkride and he said that a lot of people adjust it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder as
well if it's
| off?
|

There's no adjustments on the encoder? I can set the altimeter on the
ground to the airport elevation, so I know it should be really close
to the correct altitude, but then ATC may see my altitude as being a
hundred feet off... The encoder never needs to be recalibrated? It
just sees what is at the static input?

On Mar 20, 2:16 pm, "Jim Macklin"
wrote:
Not legal, you'll screw it up. Even an A&P is not allowed
to "adjust" instruments internally. You should take it to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.

"kevmor" wrote in message

ups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my examiner
about it on
| the checkride and he said that a lot of people adjust it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder as
well if it's
| off?
|

On Mar 22, 1:13 pm, "kevmor" wrote:
There's no adjustments on the encoder? I can set the altimeter on the
ground to the airport elevation, so I know it should be really close
to the correct altitude, but then ATC may see my altitude as being a
hundred feet off... The encoder never needs to be recalibrated? It
just sees what is at the static input?

On Mar 20, 2:16 pm, "Jim Macklin"



wrote:
Not legal, you'll screw it up. Even an A&P is not allowed
to "adjust" instruments internally. You should take it to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.

"kevmor" wrote in message

oups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my examiner
about it on
| the checkride and he said that a lot of people adjust it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder as
well if it's
| off?
|- Hide quoted text -

- Show quoted text -

The encoder sends data as if it was always set to 2992. The ground
adjusts it for local altimeter setting.

Bill Hale

That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude to ATC.
ATC computes an altitude correction factor for their own displays.
Some cockpit instrumentation computes the identical correction,
allowing the pilot to know what altitude ATC is displaying.

"kevmor" wrote in message oups.com...
There's no adjustments on the encoder? I can set the altimeter on the
ground to the airport elevation, so I know it should be really close
to the correct altitude, but then ATC may see my altitude as being a
hundred feet off... The encoder never needs to be recalibrated? It
just sees what is at the static input?

On Mar 20, 2:16 pm, "Jim Macklin"
wrote:
Not legal, you'll screw it up. Even an A&P is not allowed
to "adjust" instruments internally. You should take it to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.

"kevmor" wrote in message

ups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my examiner
about it on
| the checkride and he said that a lot of people adjust it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder as
well if it's
| off?
|

There's no user-adjustable settings on the encoder, but there are
adjustments on the encoder (assuming an encoder, not an encoding
altimeter) which can be made, assuming the unit itself is not just
busted, by an avionics shop and a transponder test set which will
bring it back into spec.

On Thu, 22 Mar 2007 15:56:42 -0400, "John R. Copeland"
wrote:

That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude to ATC.
ATC computes an altitude correction factor for their own displays.
Some cockpit instrumentation computes the identical correction,
allowing the pilot to know what altitude ATC is displaying.

"kevmor" wrote in message oups.com...
There's no adjustments on the encoder? I can set the altimeter on the
ground to the airport elevation, so I know it should be really close
to the correct altitude, but then ATC may see my altitude as being a
hundred feet off... The encoder never needs to be recalibrated? It
just sees what is at the static input?

On Mar 20, 2:16 pm, "Jim Macklin"
wrote:
Not legal, you'll screw it up. Even an A&P is not allowed
to "adjust" instruments internally. You should take it to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.

"kevmor" wrote in message

ups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my examiner
about it on
| the checkride and he said that a lot of people adjust it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder as
well if it's
| off?
|

John R. Copeland wrote:
That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude to ATC.

Make that "pressure altitude".

"Dave Butler" wrote in message ...
John R. Copeland wrote:
That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude to ATC.

Make that "pressure altitude".

Oops! I really *do* know that.
I just screwed up. Thanks, Dave.

Thanks all for your advice, I also had a problem once or twice with
this transponder on the last digit not showing correctly on their
side. ATC asked to confirm my squawk a couple times, and then I
suppose he got a supervisor who said "the last digit of your
transponder...what does it read?" He told me to rotate the knob around
a few times, which fixed it. The airplane was set on 1200 and never
changed for a decade, maybe it just needed to be cycled some

Dave Butler wrote:
John R. Copeland wrote:
That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude to ATC.

Make that "pressure altitude".

"John R. Copeland" wrote in
message ...
That is correct - there's no adjustment on the encoder.
Your encoder reports density altitude [PRESSURE ALTITUDE]
to ATC.
ATC computes an altitude correction factor for their own
displays.
Some cockpit instrumentation computes the identical
correction,
allowing the pilot to know what altitude ATC is displaying.

"kevmor" wrote in message
oups.com...
There's no adjustments on the encoder? I can set the
altimeter on the
ground to the airport elevation, so I know it should be
really close
to the correct altitude, but then ATC may see my altitude
as being a
hundred feet off... The encoder never needs to be
recalibrated? It
just sees what is at the static input?

On Mar 20, 2:16 pm, "Jim Macklin"
wrote:
Not legal, you'll screw it up. Even an A&P is not
allowed
to "adjust" instruments internally. You should take it
to a
certified repair shop if it won't pass a IFR check. The
encoder is factory set at 1013.2 mb/29.92 and there are
no
field serviceable adjustments.

If the static systems is wrong, the altimeter system and
airspeed will also likely be wrong.

"kevmor" wrote in message

ups.com...
| How can you adjust an altimeter if the pressure isn't
correct in the
| window for the altitude? I started talking to my
examiner
about it on
| the checkride and he said that a lot of people adjust
it
themselves
| (not an avionics shop, etc), and he said you take the
front off (I
| think) and theres a screw to adjust it? The plane
would
be used for
| VFR only...
|
| Is there an adjustment that can be made to the encoder
as
well if it's
| off?
|