---
kind: "section"
citation: "14 C.F.R. § 29.1323"
title: "14"
number: "29.1323"
heading: "Airspeed indicating system."
url: "https://uscodex.org/cfr/14/29.1323"
---

# §29.1323. Airspeed indicating system.


For each airspeed indicating system, the following apply:

- (a) Each airspeed indicating instrument must be calibrated to indicate true airspeed (at sea level with a standard atmosphere) with a minimum practicable instrument calibration error when the corresponding pitot and static pressures are applied.
- (b) Each system must be calibrated to determine system error excluding airspeed instrument error. This calibration must be determined—
  - (1) In level flight at speeds of 20 knots and greater, and over an appropriate range of speeds for flight conditions of climb and autorotation; and
  - (2) **During takeoff, with repeatable and readable indications that ensure—**
    - (i) Consistent realization of the field lengths specified in the Rotorcraft Flight Manual; and
    - (ii) Avoidance of the critical areas of the height-velocity envelope as established under [§ 29.87](/cfr/14/29.87.md).
- (c) **For Category A rotorcraft—**
  - (1) The indication must allow consistent definition of the takeoff decision point; and
  - (2) The system error, excluding the airspeed instrument calibration error, may not exceed—
    - (i) Three percent or 5 knots, whichever is greater, in level flight at speeds above 80 percent of takeoff safety speed; and
    - (ii) **Ten knots in climb at speeds from 10 knots below takeoff safety speed to 10 knots above V<I>Y</I>.**
- (d) For Category B rotorcraft, the system error, excluding the airspeed instrument calibration error, may not exceed 3 percent or 5 knots, whichever is greater, in level flight at speeds above 80 percent of the climbout speed attained at 50 feet when complying with [§ 29.63](/cfr/14/29.63.md).
- (e) Each system must be arranged, so far as practicable, to prevent malfunction or serious error due to the entry of moisture, dirt, or other substances.
- (f) Each system must have a heated pitot tube or an equivalent means of preventing malfunction due to icing.

## Notes

### Amendments

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as amended by Amdt. 29-3, 33 FR 970, Jan. 26, 1968; Amdt. 29-24, 49 FR 44439, Nov. 6, 1984; Amdt. 29-39, 61 FR 21901, May 10, 1996; Amdt. 29-44, 64 FR 45338, Aug. 19, 1999]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704.

### Source

Source: Docket No. 5084, 29 FR 16150, Dec. 3, 1964, unless otherwise noted.

### Amendments

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as amended by Amdt. 29-3, 33 FR 970, Jan. 26, 1968; Amdt. 29-24, 49 FR 44439, Nov. 6, 1984; Amdt. 29-39, 61 FR 21901, May 10, 1996; Amdt. 29-44, 64 FR 45338, Aug. 19, 1999]