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557 

Federal Aviation Administration, DOT 

§ 27.1519 

(b) The operating limitations and 

other information necessary for safe 
operation must be made available to 
the crewmembers as prescribed in 
§§ 27.1541 through 27.1589. 

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral 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))) 

[Amdt. 27–14, 43 FR 2325, Jan. 16, 1978] 

O

PERATING

L

IMITATIONS

 

§ 27.1503

Airspeed limitations: general. 

(a) An operating speed range must be 

established. 

(b) When airspeed limitations are a 

function of weight, weight distribution, 
altitude, rotor speed, power, or other 
factors, airspeed limitations cor-
responding with the critical combina-
tions of these factors must be estab-
lished. 

§ 27.1505

Never-exceed speed. 

(a) The never-exceed speed, V

NE,

must 

be established so that it is— 

(1) Not less than 40 knots (CAS); and 
(2) Not more than the lesser of— 
(i) 0.9 times the maximum forward 

speeds established under § 27.309; 

(ii) 0.9 times the maximum speed 

shown under §§ 27.251 and 27.629; or 

(iii) 0.9 times the maximum speed 

substantiated for advancing blade tip 
mach number effects. 

(b) V

NE

may vary with altitude, 

r.p.m., temperature, and weight, if— 

(1) No more than two of these vari-

ables (or no more than two instru-
ments 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 inte-
grating more than one of these vari-
ables) are large enough to allow an 
operationally practical and safe vari-
ation of V

NE

(c) For helicopters, a stabilized 

power-off V

NE

denoted as V

NE

(power- 

off) may be established at a speed less 
than V

NE

established pursuant to para-

graph (a) of this section, if the fol-
lowing 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) § 27.65(b) for single engine heli-

copters; and 

(ii) § 27.67 for multiengine heli-

copters. 

(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 certifi-
cation is requested, and a constant 
amount less than power-on V

NE

for the 

remainder of the altitude range. 

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral 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))) 

[Amdt. 27–2, 33 FR 964, Jan. 26, 1968, and 
Amdt. 27–14, 43 FR 2325, Jan. 16, 1978; Amdt. 
27–21, 49 FR 44435, Nov. 6, 1984] 

§ 27.1509

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. deter-

mined under § 27.309(b); and 

(2) The maximum r.p.m. shown dur-

ing the type tests. 

(b)  Minimum power off. The minimum 

power-off rotor speed must be estab-
lished 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 de-

sign substantiation. 

(c)  Minimum power on. The minimum 

power-on rotor speed must be estab-
lished 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 de-

sign substantiation; and 

(2) Not more than a value determined 

under § 27.33(a)(1) and (b)(1). 

§ 27.1519

Weight and center of gravity. 

The weight and center of gravity lim-

itations determined under §§ 27.25 and 

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