---
kind: "range"
citation: "14 C.F.R. §§ 27.49–27.87"
title: "14"
from: "27.49"
to: "27.87"
count: 7
url: "https://uscodex.org/cfr/14/27.49..27.87"
---

# §27.49. Performance at minimum operating speed.

- (a) **For helicopters—**
  - (1) The hovering ceiling must be determined over the ranges of weight, altitude, and temperature for which certification is requested, with—
    - (i) Takeoff power;
    - (ii) The landing gear extended; and
    - (iii) The helicopter in-ground effect at a height consistent with normal takeoff procedures; and
  - (2) The hovering ceiling determined under [paragraph (a)(1)](#a-1) of this section must be at least—
    - (i) For reciprocating engine powered helicopters, 4,000 feet at maximum weight with a standard atmosphere;
    - (ii) For turbine engine powered helicopters, 2,500 feet pressure altitude at maximum weight at a temperature of standard plus 22 °C (standard plus 40 °F).
  - (3) The out-of-ground effect hovering performance must be determined over the ranges of weight, altitude, and temperature for which certification is requested, using takeoff power.
- (b) For rotorcraft other than helicopters, the steady rate of climb at the minimum operating speed must be determined over the ranges of weight, altitude, and temperature for which certification is requested, with—
  - (1) Takeoff power; and
  - (2) **The landing gear extended.**

# §27.51. Takeoff.


The takeoff, with takeoff power and r.p.m. at the most critical center of gravity, and with weight from the maximum weight at sea level to the weight for which takeoff certification is requested for each altitude covered by this section—

- (a) May not require exceptional piloting skill or exceptionally favorable conditions throughout the ranges of altitude from standard sea level conditions to the maximum altitude for which takeoff and landing certification is requested, and
- (b) Must be made in such a manner that a landing can be made safely at any point along the flight path if an engine fails. This must be demonstrated up to the maximum altitude for which takeoff and landing certification is requested or 7,000 feet density altitude, whichever is less.

# §27.65. Climb: all engines operating.

- (a) **For rotorcraft other than helicopters—**
  - (1) The steady rate of climb, at VY, must be determined—
    - (i) With maximum continuous power on each engine;
    - (ii) With the landing gear retracted; and
    - (iii) For the weights, altitudes, and temperatures for which certification is requested; and
  - (2) The climb gradient, at the rate of climb determined in accordance with [paragraph (a)(1)](#a-1) of this section, must be either—
    - (i) **At least 1—** 10 if the horizontal distance required to take off and climb over a 50-foot obstacle is determined for each weight, altitude, and temperature within the range for which certification is requested; or
    - (ii) **At least 1—** 6 under standard sea level conditions.
- (b) Each helicopter must meet the following requirements:
  - (1) VY must be determined—
    - (i) For standard sea level conditions;
    - (ii) At maximum weight; and
    - (iii) **With maximum continuous power on each engine.**
  - (2) The steady rate of climb must be determined—
    - (i) At the climb speed selected by the applicant at or below VNE;
    - (ii) Within the range from sea level up to the maximum altitude for which certification is requested;
    - (iii) For the weights and temperatures that correspond to the altitude range set forth in [paragraph (b)(2)(ii)](#b-2-ii) of this section and for which certification is requested; and
    - (iv) **With maximum continuous power on each engine.**

# §27.67. Climb: one engine inoperative.


For multiengine helicopters, the steady rate of climb (or descent), at Vy (or at the speed for minimum rate of descent), must be determined with—

- (a) Maximum weight;
- (b) **The critical engine inoperative and the remaining engines at either—**
  - (1) Maximum continuous power and, for helicopters for which certification for the use of 30-minute OEI power is requested, at 30-minute OEI power; or
  - (2) Continuous OEI power for helicopters for which certification for the use of continuous OEI power is requested.

# §27.71. Autorotation performance.


For single-engine helicopters and multiengine helicopters that do not meet the Category A engine isolation requirements of [Part 29](/cfr/14/part29.md) of this chapter, the minimum rate of descent airspeed and the best angle-of-glide airspeed must be determined in autorotation at—

- (a) Maximum weight; and
- (b) **Rotor speed(s) selected by the applicant.**

# §27.75. Landing.

- (a) The rotorcraft must be able to be landed with no excessive vertical acceleration, no tendency to bounce, nose over, ground loop, porpoise, or water loop, and without exceptional piloting skill or exceptionally favorable conditions, with—
  - (1) Approach or autorotation speeds appropriate to the type of rotorcraft and selected by the applicant;
  - (2) **The approach and landing made with—**
    - (i) Power off, for single engine rotorcraft and entered from steady state autorotation; or
    - (ii) One-engine inoperative (OEI) for multiengine rotorcraft, with each operating engine within approved operating limitations, and entered from an established OEI approach.
- (b) Multiengine rotorcraft must be able to be landed safely after complete power failure under normal operating conditions.

# §27.87. Height-velocity envelope.

- (a) If there is any combination of height and forward velocity (including hover) under which a safe landing cannot be made under the applicable power failure condition in [paragraph (b)](#b) of this section, a limiting height-velocity envelope must be established (including all pertinent information) for that condition, throughout the ranges of—
  - (1) Altitude, from standard sea level conditions to the maximum altitude capability of the rotorcraft, or 7000 feet density altitude, whichever is less; and
  - (2) Weight, from the maximum weight at sea level to the weight selected by the applicant for each altitude covered by [paragraph (a)(1)](#a-1) of this section. For helicopters, the weight at altitudes above sea level may not be less than the maximum weight or the highest weight allowing hovering out-of-ground effect, whichever is lower.
- (b) **The applicable power failure conditions are—**
  - (1) For single-engine helicopters, full autorotation;
  - (2) For multiengine helicopters, OEI (where engine isolation features ensure continued operation of the remaining engines), and the remaining engine(s) within approved limits and at the minimum installed specification power available for the most critical combination of approved ambient temperature and pressure altitude resulting in 7000 feet density altitude or the maximum altitude capability of the helicopter, whichever is less, and
  - (3) **For other rotorcraft, conditions appropriate to the type.**