FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) The rotorcraft must contain --

(1) The markings and placards specified in §§29.1545 through 29.1565; and

(2) Any additional information, instrument markings, and placards required for the safe operation of the rotorcraft if it has unusual design, operating or handling characteristics.

(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.