What is the minimum never-exceed speed (VNE) for large rotorcraft under CS 29.1505?

The never-exceed speed (VNE) must not be less than 74 km/h (40 knots) (CAS).

What conditions must be met to establish a stabilised power-off VNE (VNE power-off) for helicopters according to CS 29.1505?

VNE (power-off) is not less than a speed midway between the power-on VNE and the speed used in meeting certain requirements for Category A and B helicopters, and VNE (power-off) is a constant airspeed, a constant amount less than power-on VNE, or a combination of both over different altitude ranges.

How is the never-exceed speed (VNE) established for large rotorcraft according to CS 29.1505?

The never-exceed speed, VNE, must be established so that it is not more than the lesser of: 0.9 times the maximum forward speeds established under CS 29.309; 0.9 times the maximum speed shown under CS 29.251 and 29.629; or 0.9 times the maximum speed substantiated for advancing blade tip mach number effects under critical altitude conditions.

CS 29.1505 Never-exceed speed

Q: Under what conditions can VNE vary with altitude, rpm, temperature, and weight according to CS 29.1505?

VNE may vary with altitude, rpm, temperature, and weight if no more than two of these variables (or no more than two instruments integrating more than one of these variables) are used at one time; and the ranges of these variables are large enough to allow an operationally practical and safe variation of VNE.

Q: What are the options for defining VNE (power-off) according to CS 29.1505?

VNE (power-off) can be a constant airspeed, a constant amount less than power-on VNE, or a constant airspeed for a portion of the altitude range and a constant amount less than power-on VNE for the remainder of the altitude range.

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CS 29.1505 Never-exceed speed

ED Decision 2003/16/RM

(a) The never-exceed speed, V_NE, must be established so that it is:

(1) Not less than 74 km/h (40 knots) (CAS); and

(2) Not more than the lesser of:

(i) 0.9 times the maximum forward speeds established under CS 29.309;

(ii) 0.9 times the maximum speed shown under CS 29.251 and 29.629; or

(iii) 0.9 times the maximum speed substantiated for advancing blade tip mach number effects under critical altitude conditions.

(b) V_NE may vary with altitude, rpm, temperature, and weight, if:

(1) No more than two of these variables (or no more than two instruments integrating more than one of these variables) are used at one time; and

(2) The ranges of these variables (or of the indications on instruments integrating more than one of these variables) are large enough to allow an operationally practical and safe variation of V_NE.

(c) For helicopters, a stabilised power-off V_NE denoted as V_NE (power-off) may be established at a speed less than V_NE established pursuant to sub-paragraph (a), if the following conditions are met:

(1) V_NE (power-off) is not less than a speed midway between the power-on V_NE and the speed used in meeting the requirements of:

(i) CS 29.67(a)(3) for Category A helicopters;

(ii) CS 29.65(a) for Category B helicopters, except multi-engine helicopters meeting the requirements of CS 29.67(b); and

(iii) CS 29.67(b) for multi-engine Category B helicopters meeting the requirements of CS 29.67(b).

(2) V_NE(power-off) is:

(i) A constant airspeed;

(ii) A constant amount less than power-on V_NE; or

(iii) A constant airspeed for a portion of the altitude range for which certification is requested, and a constant amount less than power-on V_NE for the remainder of the altitude range.

Details

Source-Title: CS 29.1505 Never-exceed speed

Erulesid: ERULES-1963177438-5695 Compare versions

Domain: Initial airworthiness

Amendedby: Initial issue

Applicabilitydate: 14 November, 2003

Entryintoforcedate: 14 November, 2003

Regulatorysource: ED Decision 2003/16/RM Navigate

Regulatorysubject: CS-29

Typeofcontent: CS (Certification specification)

Origin: EASA

Category: EAR