493 

Federal Aviation Administration, DOT 

§ 27.65 

(b) The performance must correspond 

to the engine power available under the 
particular ambient atmospheric condi-
tions, the particular flight condition, 
and the relative humidity specified in 
paragraphs (d) or (e) of this section, as 
appropriate. 

(c) The available power must cor-

respond to engine power, not exceeding 
the approved power, less— 

(1) Installation losses; and 
(2) The power absorbed by the acces-

sories and services appropriate to the 
particular ambient atmopheric condi-
tions and the particular flight condi-
tion. 

(d) For reciprocating engine-powered 

rotorcraft, the performance, as affected 
by engine power, must be based on a 
relative humidity of 80 percent in a 
standard atmosphere. 

(e) For turbine engine-powered rotor-

craft, the performance, as affected by 
engine power, must be based on a rel-
ative humidity of— 

(1) 80 percent, at and below standard 

temperature; and 

(2) 34 percent, at and above standard 

temperature plus 50 degrees F. Between 
these two temperatures, the relative 
humidity must vary linearly. 

(f) For turbine-engine-powered rotor-

craft, a means must be provided to per-
mit the pilot to determine prior to 
takeoff that each engine is capable of 
developing the power necessary to 
achieve the applicable rotorcraft per-
formance prescribed in this subpart. 

(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 2324, Jan. 16, 1978, as 
amended by Amdt. 27–21, 49 FR 44432, Nov. 6, 
1984] 

§ 27.49

Performance at minimum oper-

ating speed. 

(a) For helicopters— 
(1) The hovering ceiling must be de-

termined over the ranges of weight, al-
titude, and temperature for which cer-
tification is requested, with— 

(i) Takeoff power; 
(ii) The landing gear extended; and 
(iii) The helicopter in-ground effect 

at a height consistent with normal 
takeoff procedures; and 

(2) The hovering ceiling determined 

under paragraph (a)(1) of this section 
must be at least— 

(i) For reciprocating engine powered 

helicopters, 4,000 feet at maximum 
weight with a standard atmosphere; 

(ii) For turbine engine powered heli-

copters, 2,500 feet pressure altitude at 
maximum weight at a temperature of 
standard plus 22 

°

C (standard plus 40 

°

F). 

(3) The out-of-ground effect hovering 

performance must be determined over 
the ranges of weight, altitude, and 
temperature for which certification is 
requested, using takeoff power. 

(b) For rotorcraft other than heli-

copters, the steady rate of climb at the 
minimum operating speed must be de-
termined over the ranges of weight, al-
titude, and temperature for which cer-
tification is requested, with— 

(1) Takeoff power; and 
(2) The landing gear extended. 

[Amdt. 27–44, 73 FR 10998, Feb. 29, 2008] 

§ 27.51

Takeoff. 

The takeoff, with takeoff power and 

r.p.m. at the most critical center of 
gravity, and with weight from the max-
imum weight at sea level to the weight 
for which takeoff certification is re-
quested for each altitude covered by 
this section— 

(a) May not require exceptional pilot-

ing skill or exceptionally favorable 
conditions throughout the ranges of al-
titude from standard sea level condi-
tions to the maximum altitude for 
which takeoff and landing certification 
is requested, and 

(b) Must be made in such a manner 

that a landing can be made safely at 
any point along the flight path if an 
engine fails. This must be dem-
onstrated up to the maximum altitude 
for which takeoff and landing certifi-
cation is requested or 7,000 feet density 
altitude, whichever is less. 

[Amdt. 27–44, 73 FR 10999, Feb. 29, 2008] 

§ 27.65

Climb: all engines operating. 

(a) For rotorcraft other than heli-

copters— 

(1) The steady rate of climb, at 

V

Y,

 

must be determined— 

(i) With maximum continuous power 

on each engine; 

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