(a) Each airspeed indicator must be marked as specified in paragraph (b) of this section, with the marks located at the corresponding indicated airspeeds.

(b) The following markings must be made:

(1) A red line—

(i) For rotorcraft other than helicopters, at VNE.

(ii) For helicopters, at VNE (power-on).

(iii) For helicopters, at VNE (power-off). If VNE (power-off) is less than VNE (power-on) and both are simultaneously displayed, the red line at VNE (power-off) must be clearly distinguishable from the red line at VNE (power-on).

(2) [Reserved]

(3) For the caution range, a yellow range.

(4) For the normal operating range, a green or unmarked range.

(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. 27-14, 43 FR 2325, Jan. 16, 1978; 43 FR 3900, Jan. 30, 1978; Amdt. 27-16, 43 FR 50599, Oct. 30, 1978; Amdt. 27-51, 88 FR 8738, Feb. 10, 2023]