(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.