allowable compass error...

My FARAIM is at my daughter's house and I can't find anything on the 'net to
answer my questions. Please indulge me....

Scenario:
1) line up with runway centerline[for my hypothetical, the runway is
dead nuts to the compass]
2) note compass heading
3) add/subtract compass card correction

Questions:
1) How much error is allowable between known heading and corrected
compass reading?
2) Does a significant error down the airplane as unworthy?
3) Where can I find applicable references?

I searched for "compass error" on my Summit CD-ROM and got 11 hits, all
definitions except one that, when referring to radio installations, said
that the compass card had to be checked with radios both on and off, with
the max allowable deviation 10 degrees. I don't think that there are any
regs that speak directly to the situation you describe.

Bob Gardner

"Casey Wilson" N2310D @ gmail.com wrote in message
news:xQllg.2530$RU4.408@trnddc03...
My FARAIM is at my daughter's house and I can't find anything on the 'net
to answer my questions. Please indulge me....

Scenario:
1) line up with runway centerline[for my hypothetical, the runway is
dead nuts to the compass]
2) note compass heading
3) add/subtract compass card correction

Questions:
1) How much error is allowable between known heading and corrected
compass reading?
2) Does a significant error down the airplane as unworthy?
3) Where can I find applicable references?

Don't know, but if you are using the runway heading to judge whether
your compass reading is in error, remember that runway headings are not
always true. There are other ways to calibrate your compass.

Casey Wilson wrote:
My FARAIM is at my daughter's house and I can't find anything on the 'net to
answer my questions. Please indulge me....

Scenario:
1) line up with runway centerline[for my hypothetical, the runway is
dead nuts to the compass]
2) note compass heading
3) add/subtract compass card correction

Questions:
1) How much error is allowable between known heading and corrected
compass reading?
2) Does a significant error down the airplane as unworthy?
3) Where can I find applicable references?

Part 23 and Part 43.

Runways are to the nearest 5 degrees and will be renumbered
as required. During the annual inspection the compass
should be checked to be sure it is within degrees on all
headings and any time there has been a change in the
airplane that would cause the deviation to change.


Yes, an error greater than 10 degrees, even with the
correction card, requires correction.


--
James H. Macklin
ATP,CFI,A&P

"RomeoMike" wrote in message
...
| Don't know, but if you are using the runway heading to
judge whether
| your compass reading is in error, remember that runway
headings are not
| always true. There are other ways to calibrate your
compass.
|
| Casey Wilson wrote:
| My FARAIM is at my daughter's house and I can't find
anything on the 'net to
| answer my questions. Please indulge me....
|
| Scenario:
| 1) line up with runway centerline[for my
hypothetical, the runway is
| dead nuts to the compass]
| 2) note compass heading
| 3) add/subtract compass card correction
|
| Questions:
| 1) How much error is allowable between known heading
and corrected
| compass reading?
| 2) Does a significant error down the airplane as
unworthy?
| 3) Where can I find applicable references?
|
|
|

Runways are to the nearest 5 degrees and will be renumbered
as required.

Usually. LAX has five runways with the same alignment; they cheat the
numbers.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Okay, Jim, I think you said an error greater than ten degrees will ground
the airplance. I'll accept that. Can you give me the reference for the ten
degree figure? Are you saying that the airplane should be taken to the
compass rose during the annual or is there some "quick check?"

"Jim Macklin" wrote in message
news:NBplg.49163$ZW3.16236@dukeread04...
Part 23 and Part 43.

Runways are to the nearest 5 degrees and will be renumbered
as required. During the annual inspection the compass
should be checked to be sure it is within degrees on all
headings and any time there has been a change in the
airplane that would cause the deviation to change.


Yes, an error greater than 10 degrees, even with the
correction card, requires correction.


--
James H. Macklin
ATP,CFI,A&P

"RomeoMike" wrote in message
...
| Don't know, but if you are using the runway heading to
judge whether
| your compass reading is in error, remember that runway
headings are not
| always true. There are other ways to calibrate your
compass.
|
| Casey Wilson wrote:
| My FARAIM is at my daughter's house and I can't find
anything on the 'net to
| answer my questions. Please indulge me....
|
| Scenario:
| 1) line up with runway centerline[for my
hypothetical, the runway is
| dead nuts to the compass]
| 2) note compass heading
| 3) add/subtract compass card correction
|
| Questions:
| 1) How much error is allowable between known heading
and corrected
| compass reading?
| 2) Does a significant error down the airplane as
unworthy?
| 3) Where can I find applicable references?
|
|
|

§ 23.1327 Magnetic direction indicator.
(a) Except as provided in paragraph (b) of this section-

(1) Each magnetic direction indicator must be installed so
that its accuracy is not excessively affected by the
airplane's vibration or magnetic fields; and

(2) The compensated installation may not have a deviation in
level flight, greater than ten degrees on any heading.

(b) A magnetic nonstabilized direction indicator may deviate
more than ten degrees due to the operation of electrically
powered systems such as electrically heated windshields if
either a magnetic stabilized direction indicator, which does
not have a deviation in level flight greater than ten
degrees on any heading, or a gyroscopic direction indicator,
is installed. Deviations of a magnetic nonstabilized
direction indicator of more than 10 degrees must be
placarded in accordance with §23.1547(e).

[Amdt. 23-20, 42 FR 36969, July 18, 1977]


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--
James H. Macklin
ATP,CFI,A&P

"Casey Wilson" N2310D @ gmail.com wrote in message
news:0sylg.2531$DI2.2291@trnddc05...
| Okay, Jim, I think you said an error greater than ten
degrees will ground
| the airplance. I'll accept that. Can you give me the
reference for the ten
| degree figure? Are you saying that the airplane should be
taken to the
| compass rose during the annual or is there some "quick
check?"
|
| "Jim Macklin" wrote
in message
| news:NBplg.49163$ZW3.16236@dukeread04...
| Part 23 and Part 43.
|
| Runways are to the nearest 5 degrees and will be
renumbered
| as required. During the annual inspection the compass
| should be checked to be sure it is within degrees on all
| headings and any time there has been a change in the
| airplane that would cause the deviation to change.
|
|
| Yes, an error greater than 10 degrees, even with the
| correction card, requires correction.
|
|
| --
| James H. Macklin
| ATP,CFI,A&P
|
| "RomeoMike" wrote in
message
| ...
| | Don't know, but if you are using the runway heading to
| judge whether
| | your compass reading is in error, remember that runway
| headings are not
| | always true. There are other ways to calibrate your
| compass.
| |
| | Casey Wilson wrote:
| | My FARAIM is at my daughter's house and I can't find
| anything on the 'net to
| | answer my questions. Please indulge me....
| |
| | Scenario:
| | 1) line up with runway centerline[for my
| hypothetical, the runway is
| | dead nuts to the compass]
| | 2) note compass heading
| | 3) add/subtract compass card correction
| |
| | Questions:
| | 1) How much error is allowable between known
heading
| and corrected
| | compass reading?
| | 2) Does a significant error down the airplane as
| unworthy?
| | 3) Where can I find applicable references?
| |
| |
| |
|
|
|
|

Ah, Jim, finally.... thank you, thank you...

Casey


"Jim Macklin" wrote in message
news:FqFlg.49206$ZW3.9522@dukeread04...
' 23.1327 Magnetic direction indicator.
(a) Except as provided in paragraph (b) of this section-

(1) Each magnetic direction indicator must be installed so
that its accuracy is not excessively affected by the
airplane's vibration or magnetic fields; and

(2) The compensated installation may not have a deviation in
level flight, greater than ten degrees on any heading.

(b) A magnetic nonstabilized direction indicator may deviate
more than ten degrees due to the operation of electrically
powered systems such as electrically heated windshields if
either a magnetic stabilized direction indicator, which does
not have a deviation in level flight greater than ten
degrees on any heading, or a gyroscopic direction indicator,
is installed. Deviations of a magnetic nonstabilized
direction indicator of more than 10 degrees must be
placarded in accordance with '23.1547(e).

[Amdt. 23-20, 42 FR 36969, July 18, 1977]

Thanks, I know about compass roses and swinging the compass. What I'm
looking for is an indication that the compass needs swinging. That's why my
hypothetical scenario stated that the runway alignment is correct. That does
happen, by the way, even if the odds are against it.

"RomeoMike" wrote in message
...
Don't know, but if you are using the runway heading to judge whether your
compass reading is in error, remember that runway headings are not always
true. There are other ways to calibrate your compass.

Casey Wilson wrote:
My FARAIM is at my daughter's house and I can't find anything on the 'net
to answer my questions. Please indulge me....

Scenario:
1) line up with runway centerline[for my hypothetical, the runway is
dead nuts to the compass]
2) note compass heading
3) add/subtract compass card correction

Questions:
1) How much error is allowable between known heading and corrected
compass reading?
2) Does a significant error down the airplane as unworthy?
3) Where can I find applicable references?

I had a thought, what do you think? If you are tracking a radial on a VOR
couldn't you compare the radial to the compass heading and get a good idea of
the compass error?


On Mon, 19 Jun 2006 14:17:23 GMT, "Casey Wilson" N2310D @ gmail.com wrote:

Thanks, I know about compass roses and swinging the compass. What I'm
looking for is an indication that the compass needs swinging. That's why my
hypothetical scenario stated that the runway alignment is correct. That does
happen, by the way, even if the odds are against it.

GeorgeC