14 CFR 27.1541 - General.
(a) The rotorcraft must contain -
(1) The markings and placards specified in §§ 27.1545 through 27.1565, and
(b) Each marking and placard prescribed in paragraph (a) of this section -
(1) Must be displayed in a conspicuous place; and
(2) May not be easily erased, disfigured, or obscured.