562 

14 CFR Ch. I (1–1–24 Edition) 

§ 27.1523 

to multiengine, turbine-powered rotor-
craft for not longer than 30 minutes 
after failure of an engine. The use of 30- 
minute OEI power must also 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 dem-

onstrated during the type tests; 

(2) The maximum allowable gas tem-

perature; and 

(3) The maximum allowable torque. 
(i) 

Continuous OEI power operation. 

Unless otherwise authorized, the use of 
continuous OEI power must be limited 
to multiengine, turbine-powered rotor-
craft for continued flight after failure 
of an engine. The use of continuous 
OEI power must also 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 dem-

onstrated during the type tests; 

(2) The maximum allowable gas tem-

perature; and 

(3) The maximum allowable torque. 
(j) 

Rated 30-second OEI power oper-

ation.  Rated 30-second OEI power is 
permitted only on multiengine, tur-
bine-powered rotorcraft, also certifi-
cated for the use of rated 2-minute OEI 
power, and can only be used for contin-
ued operation of the remaining en-
gine(s) after a failure or precautionary 
shutdown of an engine. It must be 
shown that following application of 30- 
second OEI power, any damage will be 
readily detectable by the applicable in-
spections and other related procedures 
furnished in accordance with Section 
A27.4 of appendix A of this part and 
Section A33.4 of appendix A of part 33. 
The use of 30-second OEI power must be 
limited to not more than 30 seconds for 
any period in which that power is used, 
and 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 dem-

onstrated during the type tests; 

(2) The maximum allowable gas tem-

perature; and 

(3) The maximum allowable torque. 

(k) 

Rated 2-minute OEI power oper-

ation. Rated 2-minute OEI power is per-
mitted only on multiengine, turbine- 
powered rotorcraft, also certificated 
for the use of rated 30-second OEI 
power, and can only be used for contin-
ued operation of the remaining en-
gine(s) after a failure or precautionary 
shutdown of an engine. It must be 
shown that following application of 2- 
minute OEI power, any damage will be 
readily detectable by the applicable in-
spections and other related procedures 
furnished in accordance with Section 
A27.4 of appendix A of this part and 
Section A33.4 of appendix A of part 33. 
The use of 2-minute OEI power must be 
limited to not more than 2 minutes for 
any period in which that power is used, 
and 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 dem-

onstrated during the type tests; 

(2) The maximum allowable gas tem-

perature; and 

(3) The maximum allowable torque. 

(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. 27–14, 43 FR 2325, Jan. 16, 
1978; Amdt. 27–23, 53 FR 34214, Sept. 2, 1988; 
Amdt. 27–29, 59 FR 47767, Sept. 16, 1994] 

§ 27.1523

Minimum flight crew. 

The minimum flight crew must be es-

tablished so that it is sufficient for safe 
operation, considering— 

(a) The workload on individual crew-

members; 

(b) The accessibility and ease of oper-

ation of necessary controls by the ap-
propriate crewmember; and 

(c) The kinds of operation authorized 

under § 27.1525. 

§ 27.1525

Kinds of operations. 

The kinds of operations (such as 

VFR, IFR, day, night, or icing) for 
which the rotorcraft is approved are es-
tablished by demonstrated compliance 

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563 

Federal Aviation Administration, DOT 

§ 27.1547 

with the applicable certification re-
quirements and by the installed equip-
ment. 

[Amdt. 27–21, 49 FR 44435, Nov. 6, 1984] 

§ 27.1527

Maximum operating altitude. 

The maximum altitude up to which 

operation is allowed, as limited by 
flight, structural, powerplant, func-
tional, or equipment characteristics, 
must be established. 

(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] 

§ 27.1529

Instructions for Continued 

Airworthiness. 

The applicant must prepare Instruc-

tions for Continued Airworthiness in 
accordance with appendix A to this 
part that are acceptable to the Admin-
istrator. The instructions may be in-
complete at type certification if a pro-
gram exists to ensure their completion 
prior to delivery of the first rotorcraft 
or issuance of a standard certificate of 
airworthiness, whichever occurs later. 

[Amdt. 27–18, 45 FR 60177, Sept. 11, 1980] 

M

ARKINGS AND

P

LACARDS

 

§ 27.1541

General. 

(a) The rotorcraft must contain— 
(1) The markings and placards speci-

fied in §§ 27.1545 through 27.1565, and 

(2) Any additional information, in-

strument markings, and placards re-
quired for the safe operation of rotor-
craft with unusual design, operating or 
handling characteristics. 

(b) Each marking and placard pre-

scribed in paragraph (a) of this sec-
tion— 

(1) Must be displayed in a con-

spicuous place; and 

(2) May not be easily erased, dis-

figured, or obscured. 

§ 27.1543

Instrument markings: gen-

eral. 

For each instrument— 
(a) When markings are on the cover 

glass of the instrument, there must be 
means to maintain the correct align-

ment of the glass cover with the face of 
the dial; and 

(b) Each arc and line must be wide 

enough, and located, to be clearly visi-
ble to the pilot. 

§ 27.1545

Airspeed indicator. 

(a) Each airspeed indicator must be 

marked as specified in paragraph (b) of 
this section, with the marks located at 
the corresponding indicated airspeeds. 

(b) The following markings must be 

made: 

(1) A red line— 
(i) For rotorcraft other than heli-

copters, at V

NE

. 

(ii) For helicopters, at V

NE

(power- 

on). 

(iii) For helicopters, at V

NE

(power- 

off). If V

NE

(power-off) is less than V

NE

 

(power-on) and both are simulta-
neously displayed, the red line at V

NE

 

(power-off) must be clearly distinguish-
able from the red line at V

NE

(power- 

on). 

(2) [Reserved] 
(3) For the caution range, a yellow 

range. 

(4) For the normal operating range, a 

green or unmarked 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))) 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–14, 43 FR 2325, Jan. 16, 
1978; 43 FR 3900, Jan. 30, 1978; Amdt. 27–16, 43 
FR 50599, Oct. 30, 1978; Amdt. 27–51, 88 FR 
8738, Feb. 10, 2023] 

§ 27.1547

Magnetic direction indicator. 

(a) A placard meeting the require-

ments of this section must be installed 
on or near the magnetic direction indi-
cator. 

(b) The placard must show the cali-

bration of the instrument in level 
flight with the engines operating. 

(c) The placard must state whether 

the calibration was made with radio re-
ceivers on or off. 

(d) Each calibration reading must be 

in terms of magnetic heading in not 
more than 45 degree increments. 

(e) If a magnetic nonstabilized direc-

tion indicator can have a deviation of 
more than 10 degrees caused by the op-
eration of electrical equipment, the 

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