§ 27.1509 Rotor speed.

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Title 14 CFR: Aeronautics and Space › Chapter I: FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION › Part 27: AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT › Subpart G: Operating Limitations and Information › § 27.1509: § 27.1509 Rotor speed.

This text was captured on Aug 14, 2026. It is a snapshot, not a live feed, so check the official code before relying on it.

Text

(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 § 27.309(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 § 27.33(a)(1) and (b)(1).

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