496 

14 CFR Ch. I (1–1–24 Edition) 

§ 27.151 

(vi) Landing (power on and power 

off); and 

(vii) Recovery to power-on flight 

from a balked autorotative approach. 

(b) The margin of cyclic control must 

allow satisfactory roll and pitch con-
trol at V

NE

with— 

(1) Critical weight; 
(2) Critical center of gravity; 
(3) Critical rotor r.p.m.; and 
(4) Power off (except for helicopters 

demonstrating compliance with para-
graph (f) of this section) and power on. 

(c) Wind velocities from zero to at 

least 17 knots, from all azimuths, must 
be established in which the rotorcraft 
can be operated without loss of control 
on or near the ground in any maneuver 
appropriate to the type (such as cross-
wind takeoffs, sideward flight, and 
rearward flight)— 

(1) With altitude, from standard sea 

level conditions to the maximum take-
off and landing altitude capability of 
the rotorcraft or 7000 feet density alti-
tude, whichever is less; with— 

(i) Critical Weight; 
(ii) Critical center of gravity; 
(iii) Critical rotor r.p.m.; 
(2) For takeoff and landing altitudes 

above 7000 feet density altitude with— 

(i) Weight selected by the applicant; 
(ii) Critical center of gravity; and 
(iii) Critical rotor r.p.m. 
(d) Wind velocities from zero to at 

least 17 knots, from all azimuths, must 
be established in which the rotorcraft 
can be operated without loss of control 
out-of-ground-effect, with— 

(1) Weight selected by the applicant; 
(2) Critical center of gravity; 
(3) Rotor r.p.m. selected by the appli-

cant; and 

(4) Altitude, from standard sea level 

conditions to the maximum takeoff 
and landing altitude capability of the 
rotorcraft. 

(e) The rotorcraft, after (1) failure of 

one engine in the case of multiengine 
rotorcraft that meet Transport Cat-
egory A engine isolation requirements, 
or (2) complete engine failure in the 
case of other rotorcraft, must be con-
trollable over the range of speeds and 
altitudes for which certification is re-
quested when such power failure occurs 
with maximum continuous power and 
critical weight. No corrective action 

time delay for any condition following 
power failure may be less than— 

(i) For the cruise condition, one sec-

ond, or normal pilot reaction time 
(whichever is greater); and 

(ii) For any other condition, normal 

pilot reaction time. 

(f) For helicopters for which a V

NE

 

(power-off) is established under 
§ 27.1505(c), compliance must be dem-
onstrated with the following require-
ments with critical weight, critical 
center of gravity, and critical rotor 
r.p.m.: 

(1) The helicopter must be safely 

slowed to V

NE

(power-off), without ex-

ceptional pilot skill, after the last op-
erating engine is made inoperative at 
power-on V

NE.

 

(2) At a speed of 1.1 V

NE

(power-off), 

the margin of cyclic control must 
allow satisfactory roll and pitch con-
trol with power off. 

(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))) 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–2, 33 FR 963, Jan. 26, 
1968; Amdt. 27–14, 43 FR 2325, Jan. 16, 1978; 
Amdt. 27–21, 49 FR 44433, Nov. 6, 1984; Amdt. 
27–44, 73 FR 10999, Feb. 29, 2008] 

§ 27.151

Flight controls. 

(a) Longitudinal, lateral, directional, 

and collective controls may not exhibit 
excessive breakout force, friction, or 
preload. 

(b) Control system forces and free 

play may not inhibit a smooth, direct 
rotorcraft response to control system 
input. 

[Amdt. 27–21, 49 FR 44433, Nov. 6, 1984] 

§ 27.161

Trim control. 

The trim control— 
(a) Must trim any steady longitu-

dinal, lateral, and collective control 
forces to zero in level flight at any ap-
propriate speed; and 

(b) May not introduce any undesir-

able discontinuities in control force 
gradients. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–21, 49 FR 44433, Nov. 6, 
1984] 

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