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14 CFR Ch. I (1–1–24 Edition) 

§ 29.1509 

§ 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. deter-

mined under § 29.309(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 § 29.33 (a)(1) and (c)(1). 

§ 29.1517

Limiting height-velocity en-

velope. 

For Category A rotorcraft, if a range 

of heights exists at any speed, includ-
ing zero, within which it is not possible 
to make a safe landing following power 
failure, the range of heights and its 
variation with forward speed must be 
established, together with any other 
pertinent information, such as the kind 
of landing surface. 

[Amdt. 29–21, 48 FR 4391, Jan. 31, 1983, as 
amended by Amdt. 29–59, 88 FR 8739, Feb. 10, 
2023] 

§ 29.1519

Weight and center of gravity. 

The weight and center of gravity lim-

itations determined under §§ 29.25 and 
29.27, respectively, must be established 
as operating limitations. 

§ 29.1521

Powerplant limitations. 

(a) 

General.  The powerplant limita-

tions prescribed in this section must be 
established so that they do not exceed 
the corresponding limits for which the 
engines are type certificated. 

(b) 

Takeoff operation. The powerplant 

takeoff operation must be limited by— 

(1) The maximum rotational speed, 

which may not be greater than— 

(i) The maximum value determined 

by the rotor design; or 

(ii) The maximum value shown dur-

ing the type tests; 

(2) The maximum allowable manifold 

pressure (for reciprocating engines); 

(3) The maximum allowable turbine 

inlet or turbine outlet gas temperature 
(for turbine engines); 

(4) The maximum allowable power or 

torque for each engine, considering the 
power input limitations of the trans-
mission with all engines operating; 

(5) The maximum allowable power or 

torque for each engine considering the 
power input limitations of the trans-
mission with one engine inoperative; 

(6) The time limit for the use of the 

power corresponding to the limitations 
established in paragraphs (b)(1) 
through (5) of this section; and 

(7) If the time limit established in 

paragraph (b)(6) of this section exceeds 
2 minutes— 

(i) The maximum allowable cylinder 

head or coolant outlet temperature (for 
reciprocating engines); and 

(ii) The maximum allowable engine 

and transmission oil temperatures. 

(c) 

Continuous operation. The contin-

uous operation must be limited by— 

(1) The maximum rotational speed, 

which may not be greater than— 

(i) The maximum value determined 

by the rotor design; or 

(ii) The maximum value shown dur-

ing the type tests; 

(2) The minimum rotational speed 

shown under the rotor speed require-
ments in § 29.1509(c). 

(3) The maximum allowable manifold 

pressure (for reciprocating engines); 

(4) The maximum allowable turbine 

inlet or turbine outlet gas temperature 
(for turbine engines); 

(5) The maximum allowable power or 

torque for each engine, considering the 
power input limitations of the trans-
mission with all engines operating; 

(6) The maximum allowable power or 

torque for each engine, considering the 
power input limitations of the trans-
mission with one engine inoperative; 
and 

(7) The maximum allowable tempera-

tures for— 

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