Sec. 27.1547 - Magnetic direction indicator.
(a) A placard meeting the requirements of this section must be installed on or near the 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 heading in not more than 45 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. (Secs. 313(a), 601, 603, 604, and 605 of the Federal Aviation Act
of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424, and 1425); and sec. 6(c) of
the Dept. of Transportation Act (49 U.S.C. 1655(c)))
[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as amended by Amdt.
27-13, 42 FR 36972, July 18, 1977]