Compass swinging?

Stache wrote:
Roy Smith wrote:
I've got AC 43.13-1B, which describes the procedure to swing a compass.
What I can't find is the bureaucratic stuff -- who can do it (any pilot?),
and what paperwork follow-up is required (airframe logbook entry, or is
just making the new compass card sufficient?).


Recently the compass rose has come up office conversation and who,
when, how, and what type of compass survey should be accomplished. I
can assure everyone reading this not all airport have a surveyed
compass rose (calibrated). Many airports have compass roses that may
not be accurate due to underground pipes or other metal objects that
will affect the accuracy of the survey.

The FAA has published a document FAA No. 405, Standards for
Aeronautical Surveys and Related Products that explains why and how a
compass rose should be surveyed.

Next who can perform the calibration to your onboard compass installed
in your aircraft? Only a Repair station with the proper ratings with
the proper training, current manuals available, and proper tooling.
This is where it may get sticky for some. FAR 65 Subpart D for
Mechanics does NOT allow Airframe rated mechanic to calibrate
compasses. Only a repair station with the proper rating can perform
this task. FAR 65.81(a) excluded airframe mechanics form performing
maintenance, major repairs to, and major alterations of, propellers,
and any repair to, or alterations of instruments. FAR 1.1 under
maintenance explains calibrations are considered a repair. So this
just leaves repair stations to adjust your compass.

Needless to say a pilot cannot perform this task as it is not
considered preventive maintenance.

AC 43.13-1B does explain how to perform a compass swing and is
acceptable data however the compass rose has to be surveyed to make it
legal. The repair station will make an airframe record entry stated
what data the followed such as AC 43.13-1B, chapter 1, section 3. FAR
23.1327 explain the installed compass has to be accurate and all
compasses are classified as instruments.

Bottom line is the compass rose has to be surveyed (check with your
local airport) and a repair station has to perform the compass swing
and make a airframe record entry.

Stache


When we discussed this topic on another web page I posted this question
to the FAA , and here is the answer I got from them.

An A&P mechanic is authorized to approve an aircraft for return to
service after performing a compass swing. Adjustment of the readily
available compensating adjustments of a wet compass are included in
the
procedures described in AC 43.13-1B Chapter 12, Section 3.

While the FAA believes that the calibration and repair of all
instruments should be classified as appliance major repairs, which
an
A&P mechanic is not authorized to approve and return to service (see
14
CFR §65.85(a)), calibration procedures normally require the
instrument
case to be opened, special skill and knowledge, and the use of test
equipment. Calibration does not include those adjustments of
instruments and equipment which are accomplished using readily
accessible simple adjusting means that do not have an appreciable
effect
on the airworthiness of the instrument. Swinging a compass,
adjusting
the compensators to minimize error, and preparation of a compass
correction card is typically considered minor airframe maintenance.


Charles Fellows
Federal Aviation Administration
General Aviation & Avionics Branch, AFS-350
Phone (202) 267-3922
Fax (202) 267-5115

I hope this clearifies the question of who can swing a compass

Tom Downey A&P-IA

In article . com,
wrote:

Stache wrote:
Roy Smith wrote:
I've got AC 43.13-1B, which describes the procedure to swing a compass.
What I can't find is the bureaucratic stuff -- who can do it (any pilot?),
and what paperwork follow-up is required (airframe logbook entry, or is
just making the new compass card sufficient?).


Recently the compass rose has come up office conversation and who,
when, how, and what type of compass survey should be accomplished. I
can assure everyone reading this not all airport have a surveyed
compass rose (calibrated). Many airports have compass roses that may
not be accurate due to underground pipes or other metal objects that
will affect the accuracy of the survey.

The FAA has published a document FAA No. 405, Standards for
Aeronautical Surveys and Related Products that explains why and how a
compass rose should be surveyed.

Next who can perform the calibration to your onboard compass installed
in your aircraft? Only a Repair station with the proper ratings with
the proper training, current manuals available, and proper tooling.
This is where it may get sticky for some. FAR 65 Subpart D for
Mechanics does NOT allow Airframe rated mechanic to calibrate
compasses. Only a repair station with the proper rating can perform
this task. FAR 65.81(a) excluded airframe mechanics form performing
maintenance, major repairs to, and major alterations of, propellers,
and any repair to, or alterations of instruments. FAR 1.1 under
maintenance explains calibrations are considered a repair. So this
just leaves repair stations to adjust your compass.

Needless to say a pilot cannot perform this task as it is not
considered preventive maintenance.

AC 43.13-1B does explain how to perform a compass swing and is
acceptable data however the compass rose has to be surveyed to make it
legal. The repair station will make an airframe record entry stated
what data the followed such as AC 43.13-1B, chapter 1, section 3. FAR
23.1327 explain the installed compass has to be accurate and all
compasses are classified as instruments.

Bottom line is the compass rose has to be surveyed (check with your
local airport) and a repair station has to perform the compass swing
and make a airframe record entry.

Stache


When we discussed this topic on another web page I posted this question
to the FAA , and here is the answer I got from them.

An A&P mechanic is authorized to approve an aircraft for return to
service after performing a compass swing. Adjustment of the readily
available compensating adjustments of a wet compass are included in
the
procedures described in AC 43.13-1B Chapter 12, Section 3.

While the FAA believes that the calibration and repair of all
instruments should be classified as appliance major repairs, which
an
A&P mechanic is not authorized to approve and return to service (see
14
CFR ?65.85(a)), calibration procedures normally require the
instrument
case to be opened, special skill and knowledge, and the use of test
equipment. Calibration does not include those adjustments of
instruments and equipment which are accomplished using readily
accessible simple adjusting means that do not have an appreciable
effect
on the airworthiness of the instrument. Swinging a compass,
adjusting
the compensators to minimize error, and preparation of a compass
correction card is typically considered minor airframe maintenance.


Charles Fellows
Federal Aviation Administration
General Aviation & Avionics Branch, AFS-350
Phone (202) 267-3922
Fax (202) 267-5115

I hope this clearifies the question of who can swing a compass

Tom Downey A&P-IA

Thanks! That does indeed answer the question.

M wrote:
RST Engineering wrote:
C'mon Roy, you've been around airplanes long enough to know the real
answer -- "Why that compass card has been in the airplane since I bought
it."


Same reaction here. Doesn't everyone here have at least two GPS's
onboard that show a ground track bearing 10 times better than the
compass?

No, and you won't either next time your alternator decides to go
south.

Dan

wrote:

No, and you won't either next time your alternator decides to go
south.

Alternator? We don't need no steenkin' alternator!

Both the avaiation GPS on my panel, and the portable hiking unit in my
bag have alkaline power. The hiking unit even has a magnetic compass
and barometric altimeter.

I also have spare alkalines in my bag and flashlights. G

wrote in message
ps.com...

M wrote:
RST Engineering wrote:
C'mon Roy, you've been around airplanes long enough to know the real
answer -- "Why that compass card has been in the airplane since I
bought
it."


Same reaction here. Doesn't everyone here have at least two GPS's
onboard that show a ground track bearing 10 times better than the
compass?

No, and you won't either next time your alternator decides to go
south.

Gee, Dan! Do you sleep in a house? You know, you'd be squashed like a bug
when your roof collapses!


--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

Matt Barrow wrote:
wrote in message
ps.com...

M wrote:
RST Engineering wrote:
C'mon Roy, you've been around airplanes long enough to know the real
answer -- "Why that compass card has been in the airplane since I
bought
it."


Same reaction here. Doesn't everyone here have at least two GPS's
onboard that show a ground track bearing 10 times better than the
compass?

No, and you won't either next time your alternator decides to go
south.

Gee, Dan! Do you sleep in a house? You know, you'd be squashed like a bug
when your roof collapses!


Don't be dumb. The magnetic compass is legally required because it
operates independently of any electrical supply, unlike any other
navigational doodad you might have. And in some areas we fly here in
Canada, the mag compass has saved a lot of lives when the rest of the
goodies failed. An accurate compass and a pilot able to use it is
absolutely necessary for finding the way home when other stuff quits,
especially the GPS. There are no other navaids in much of this country.
When the visiblility is low, you can miss your airport by a mile or two
and never see it. A one-degree error on a 60-mile track is a mile off
course, so we teach some of our navigation exercises in an airplane
with nothing more than a compass. We have had alternator failures
several times over the years, even with carrying out the 500-hour
alternator inspections.
On the other hand, the compass is mostly useless in the far
North due to magnetic dip. Up there pilots sometimes keep the "sun's
true bearing" tables aboard.

Dan

wrote:
: Don't be dumb. The magnetic compass is legally required because it
: operates independently of any electrical supply, unlike any other
: navigational doodad you might have. And in some areas we fly here in
: Canada, the mag compass has saved a lot of lives when the rest of the
: goodies failed. An accurate compass and a pilot able to use it is
: absolutely necessary for finding the way home when other stuff quits,
: especially the GPS. There are no other navaids in much of this country.
: When the visiblility is low, you can miss your airport by a mile or two
: and never see it. A one-degree error on a 60-mile track is a mile off
: course, so we teach some of our navigation exercises in an airplane
: with nothing more than a compass. We have had alternator failures
: several times over the years, even with carrying out the 500-hour
: alternator inspections.
: On the other hand, the compass is mostly useless in the far
: North due to magnetic dip. Up there pilots sometimes keep the "sun's
: true bearing" tables aboard.

: Dan

Pretty telling a year or so ago flying along the Alaska Highway in the Yukon. A 60 mile long Victor airway between two VORs
might have as much as a 5 degree difference from end-to-end headings and "180-degreee reciprocal" headings. In the far Canadian
north, I know it's even worse.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

On Mon, 18 Dec 2006 11:48:14 -0500, B A R R Y
wrote:

wrote:

No, and you won't either next time your alternator decides to go
south.

Alternator? We don't need no steenkin' alternator!

Both the avaiation GPS on my panel, and the portable hiking unit in my
bag have alkaline power. The hiking unit even has a magnetic compass
and barometric altimeter.

I also have spare alkalines in my bag and flashlights. G

And when the GPS signal goes out? It's happened twice. OTOH we're
near the bottom of the solar cycle. BUT OT OH there was a major class
9 coronal mass ejection a week or so ago which fortunately missed us.


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

wrote in message
oups.com...

Matt Barrow wrote:
wrote in message
ps.com...

M wrote:
RST Engineering wrote:
C'mon Roy, you've been around airplanes long enough to know the real
answer -- "Why that compass card has been in the airplane since I
bought
it."


Same reaction here. Doesn't everyone here have at least two GPS's
onboard that show a ground track bearing 10 times better than the
compass?

No, and you won't either next time your alternator decides to go
south.

Gee, Dan! Do you sleep in a house? You know, you'd be squashed like a bug
when your roof collapses!


Don't be dumb.

Well bless my stars (as my grandfather used to say), that's a great CYA!

The magnetic compass is legally required because it
operates independently of any electrical supply, unlike any other
navigational doodad you might have.

Duh!

And in some areas we fly here in
Canada, the mag compass has saved a lot of lives when the rest of the
goodies failed.

And how many died because they navigated by compass alone and got hopelessly
lost or ran into something...like a mountain?

Matt Barrow wrote:
wrote in message
And how many died because they navigated by compass alone and got hopelessly
lost or ran into something...like a mountain?

People who run into mountains aren't using their eyes, much less
the compass. That's what VFR minima are for. Anyone in the mountains in
low viz is likely to die and it's not the compass' (or the
government's) fault. IFR minima require a flight altitude 2000' above
the peaks.
As I said befo Your fancy electronics (and gyros, too) can
die from any number of diseases, leaving you with only your magnetic
compass, and if it isn't accurate (and you don't have your VNC handy
and know exactly where you are) you might regret it. At least the mag
compass will continue to work much more reliably than the electronics.
ELTs are another item often ignored, and we've heard the stories
of the guys down in the bush, watching the search planes fly over
looking for that needle in the haystack while they think about their
ELT with the long-expired battery. They've just bought the farm for the
price of an ELT battery and recertification. The diaries they leave
behind are sad.

Dan