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