14 CFR § 29.1509 - Rotor speed.

---
identifier: "/us/cfr/t14/s29.1509"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "14 CFR § 29.1509 - Rotor speed."
title_number: 14
title_name: "Aeronautics and Space"
section_number: "29.1509"
section_name: "Rotor speed."
chapter_name: "FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
subchapter_number: "C"
subchapter_name: "AIRCRAFT"
part_number: "29"
part_name: "AIRWORTHINESS STANDARDS: TRANSPORT 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. 5084, 29 FR 16150, Dec. 3, 1964, unless otherwise noted."
cfr_part: "29"
---


# 29.1509 Rotor speed.

(a) *Maximum power-off (autorotation).* The maximum power-off rotor speed must be established so that it does not exceed 95 percent of the lesser of—

(1) The maximum design r.p.m. determined under § 29.309(b); and

(2) The maximum r.p.m. shown during the type tests.

(b) *Minimum power-off.* The minimum power-off rotor speed must be established so that it is not less than 105 percent of the greater of—

(1) The minimum shown during the type tests; and

(2) The minimum determined by design substantiation.

(c) *Minimum power-on.* The minimum power-on rotor speed must be established so that it is—

(1) Not less than the greater of—

(i) The minimum shown during the type tests; and

(ii) The minimum determined by design substantiation; and

(2) Not more than a value determined under § 29.33 (a)(1) and (c)(1).