14 CFR § 27.175 - Demonstration of static longitudinal stability.

---
identifier: "/us/cfr/t14/s27.175"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 27.175 - Demonstration of static longitudinal stability."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "27.175"
section_name: "Demonstration of static longitudinal stability."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "27"
part_name: "AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704."
regulatory_source: "Docket No. 5074, 29 FR 15695, Nov. 24, 1964, unless otherwise noted."
cfr_part: "27"
---


# 27.175 Demonstration of static longitudinal stability.

(a) *Climb.* Static longitudinal stability must be shown in the climb condition at speeds from Vy − 10 kt to Vy + 10 kt with—

(1) Critical weight;

(2) Critical center of gravity;

(3) Maximum continuous power;

(4) The landing gear retracted; and

(5) The rotorcraft trimmed at *V*<sub>Y.</sub>

(b) *Cruise.* Static longitudinal stability must be shown in the cruise condition at speeds from 0.8 V<sub>NE</sub> − 10 kt to 0.8 V<sub>NE</sub> + 10 kt or, if V<sub>H</sub> is less than 0.8 V<sub>NE</sub>, from V<sub>H</sub> −10 kt to V<sub>H</sub> + 10 kt, with—

(1) Critical weight;

(2) Critical center of gravity;

(3) Power for level flight at 0.8 V<sub>NE</sub> or V<sub>H</sub>, whichever is less;

(4) The landing gear retracted; and

(5) The rotorcraft trimmed at 0.8 V<sub>NE</sub> or V<sub>H</sub>, whichever is less.

(c) *V*<sub>NE.</sub> Static longitudinal stability must be shown at speeds from V<sub>NE</sub> − 20 kt to V<sub>NE</sub> with—

(1) Critical weight;

(2) Critical center of gravity;

(3) Power required for level flight at V<sub>NE</sub> −10 kt or maximum continuous power, whichever is less;

(4) The landing gear retracted; and

(5) The rotorcraft trimmed at V<sub>NE</sub> − 10 kt.

(d) *Autorotation.* Static longitudinal stability must be shown in autorotation at—

(1) Airspeeds from the minimum rate of descent airspeed−10 kt to the minimum rate of descent airspeed + 10 kt, with—

(i) Critical weight;

(ii) Critical center of gravity;

(iii) The landing gear extended; and

(iv) The rotorcraft trimmed at the minimum rate of descent airspeed.

(2) Airspeeds from best angle-of-glide airspeed−10 kt to the best angle-of-glide airspeed + 10 kt, with—

(i) Critical weight;

(ii) Critical center of gravity;

(iii) The landing gear retracted; and

(iv) The rotorcraft trimmed at the best angle-of-glide airspeed.

(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. 27-2, 33 FR 963, Jan. 26, 1968; Amdt. 27-11, 41 FR 55468, Dec. 20, 1976; Amdt. 27-14, 43 FR 2325, Jan. 16, 1978; Amdt. 27-21, 49 FR 44433, Nov. 6, 1984; Amdt. 27-34, 62 FR 46173, Aug. 29, 1997; Amdt. 27-44, 73 FR 10999, Feb. 29, 2008]