Magnetic Direction Indicator
Does the D10A remote compass meet the requirements set forth by FAR 91.205 (b)3, (magnetic direction indicator)? Is a traditional compass still required? I know one of you DARs has the answer.
Thanks
Jeff
Jeff,
Several weeks ago I started a thread about the requirement for a compass correction card. I am reposting the response that I received from a Fed who actually writes these regulations. You may find his response informative and is posted below:
With the help of a friend, who knows one of the regulation writers in DC, we recieved a very informative response posted below:
You can find the requirement for a compass (magnetic direction indicator)
at Title 14 of the Code of Federal Regulations (14 CFR) section 91.205
(b)(3).
BTW, you can find the latest regulations at:
http://ecfr.gpoaccess.gov/
Go to Title 14 and you can figure out the rest.
14 CFR § 91.205 Powered civil aircraft with
standard category U.S.
airworthiness certificates: Instrument and equipment requirements.
(a) General. Except as provided in paragraphs (c)(3) and (e) of this
section, no person may operate a powered civil aircraft with a
standard category U.S. airworthiness certificate in any operation
described in paragraphs (b) through (f) of this section unless that
aircraft contains the instruments and equipment specified in those
paragraphs (or FAA-approved equivalents) for that type of operation,
and those instruments and items of equipment are in operable
condition.
(b) Visual-flight rules (day). For VFR flight during the day,
the following instruments and equipment are required:
(3) Magnetic direction indicator.
Now if you go to the type certification rules (airworthiness requirements)
to 14 CFR 23.1547 and 25.1547, you will find the requirement for a compass,
complete with compass card, or placard as the regulations call it.
14
CFR § 23.1547 Magnetic direction indicator.
(a) A placard meeting the requirements of this section must be
installed on or near the magnetic direction indicator.
(b) The placard must show the calibration of the instrument in level
flight with the engines operating.
(c) The placard must state whether the calibration was made with
radio receivers on or off.
(d) Each calibration reading must be in terms of magnetic headings in
not more than 30 degree increments.
(e) If a magnetic nonstabilized direction indicator can have a
deviation of more than 10 degrees caused by the operation of
electrical equipment, the placard must state which electrical loads,
or combination of loads, would cause a deviation of more than 10
degrees when turned on.
So the type certification requirements require a compass card for
airworthiness certification. So unless the aircraft is properly altered
with something other than a magnetic direction indicator, a compass card is
required for a aircraft with a standard category certificate of
airworthiness.
TSO C7e for non stabilized magnetic direction indicators also figures in
there also. The manufacturer’s technical documents will usually indicate
that the compass card is part of the magnetic direction indicator system.
Now looking at homebuilt/experimental is quite another matter. These
aircraft are outside the scope of § 91.205 as well as the type
certification rules, however, if the aircraft with an experimental
certificate has previously held a standard category certificate of
airworthiness, then those requirements still apply unless otherwise
modified by the experimental nature of the aircraft.
Homebuilts can have just about anything the builder wants.
Both aircraft having a special certificate of airworthiness in the
experimental classification and homebuilts come under the operating
limitations outlined at 14 CFR § 91.319 which, among a plethora of other
restrictions, restrict those aircraft to VFR day only.
However, after all of that, there is no regulation that would prevent an
operator from accomplishing a compass calibration procedure and installing
a compass deviation placard when the regulations do not otherwise require
one.
Anyway, hope this helps
Best Regards
Russ
Russell S. Unangst, Jr.
Technical Advisor, Airworthiness
FAA Headquarters/Flight Standards Service, AFS-305
5th Fl, 950 L'Enfant Plaza, SW
Washington, DC 20024
202-385-6440