Text in force at CS29-12: from CS29-12, effective 10 Dec 2024.
(a) Each airspeed indicator must be marked as specified in sub-paragraph (b), 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; and
(ii) For helicopters, at VNE (power-on).
(2) A red, cross-hatched line at VNE (power-off) for helicopters, if VNE (power- off) is less than VNE (power-on).
(3) For the caution range, a yellow range.
(4) For the safe operating range, a green or unmarked range.
ED Decision 2024/009/R · Source