495 

Federal Aviation Administration, DOT 

§ 27.143 

§ 27.87

Height-velocity envelope. 

(a) If there is any combination of 

height and forward velocity (including 
hover) under which a safe landing can-
not be made under the applicable power 
failure condition in paragraph (b) of 
this section, a limiting height-velocity 
envelope must be established (includ-
ing all pertinent information) for that 
condition, throughout the ranges of— 

(1) Altitude, from standard sea level 

conditions to the maximum altitude 
capability of the rotorcraft, or 7000 feet 
density altitude, whichever is less; and 

(2) Weight, from the maximum 

weight at sea level to the weight se-
lected by the applicant for each alti-
tude covered by paragraph (a)(1) of this 
section. For helicopters, the weight at 
altitudes above sea level may not be 
less than the maximum weight or the 
highest weight allowing hovering out- 
of-ground effect, whichever is lower. 

(b) The applicable power failure con-

ditions are— 

(1) For single-engine helicopters, full 

autorotation; 

(2) For multiengine helicopters, OEI 

(where engine isolation features ensure 
continued operation of the remaining 
engines), and the remaining engine(s) 
within approved limits and at the min-
imum installed specification power 
available for the most critical com-
bination of approved ambient tempera-
ture and pressure altitude resulting in 
7000 feet density altitude or the max-
imum altitude capability of the heli-
copter, whichever is less, and 

(3) For other rotorcraft, conditions 

appropriate to the type. 

(Secs. 313(a), 601, 603, 604, Federal Aviation 
Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, 1424), 
sec. 6(c), Dept. of Transportation Act (49 
U.S.C. 1655(c))) 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–14, 43 FR 2324, Jan. 16, 
1978; Amdt. 27–21, 49 FR 44433, Nov. 6, 1984; 
Amdt. 27–44, 73 FR 10999, Feb. 29, 2008; Amdt. 
27–51, 88 FR 8737, Feb. 10, 2023] 

F

LIGHT

C

HARACTERISTICS

 

§ 27.141

General. 

The rotorcraft must— 
(a) Except as specifically required in 

the applicable section, meet the flight 
characteristics requirements of this 
subpart— 

(1) At the altitudes and temperatures 

expected in operation; 

(2) Under any critical loading condi-

tion within the range of weights and 
centers of gravity for which certifi-
cation is requested; 

(3) For power-on operations, under 

any condition of speed, power, and 
rotor r.p.m. for which certification is 
requested; and 

(4) For power-off operations, under 

any condition of speed and rotor r.p.m. 
for which certification is requested 
that is attainable with the controls 
rigged in accordance with the approved 
rigging instructions and tolerances; 

(b) Be able to maintain any required 

flight condition and make a smooth 
transition from any flight condition to 
any other flight condition without ex-
ceptional piloting skill, alertness, or 
strength, and without danger of ex-
ceeding the limit load factor under any 
operating condition probable for the 
type, including— 

(1) Sudden failure of one engine, for 

multiengine rotorcraft meeting Trans-
port Category A engine isolation re-
quirements of Part 29 of this chapter; 

(2) Sudden, complete power failure 

for other rotorcraft; and 

(3) Sudden, complete control system 

failures specified in § 27.695 of this part; 
and 

(c) Have any additional char-

acteristic required for night or instru-
ment operation, if certification for 
those kinds of operation is requested. 
Requirements for helicopter instru-
ment flight are contained in appendix 
B of this part. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–2, 33 FR 962, Jan. 26, 
1968; Amdt. 27–11, 41 FR 55468, Dec. 20, 1976; 
Amdt. 27–19, 48 FR 4389, Jan. 31, 1983; Amdt. 
27–21, 49 FR 44433, Nov. 6, 1984] 

§ 27.143

Controllability and maneuver-

ability. 

(a) The rotorcraft must be safely con-

trollable and maneuverable— 

(1) During steady flight; and 
(2) During any maneuver appropriate 

to the type, including— 

(i) Takeoff; 
(ii) Climb; 
(iii) Level flight; 
(iv) Turning flight; 
(v) Autorotation; 

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