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555 

Federal Aviation Administration, DOT 

§ 27.1411 

(b) Externally hung lights may be 

used. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–2, 33 FR 964, Jan. 26, 
1968] 

§ 27.1401

Anticollision light system. 

(a) 

General. 

If certification for night 

operation is requested, the rotorcraft 
must have an anticollision light sys-
tem that— 

(1) Consists of one or more approved 

anticollision lights located so that 
their emitted light will not impair the 
crew’s vision or detract from the con-
spicuity of the position lights; and 

(2) Meets the requirements of para-

graphs (b) through (f) of this section. 

(b) 

Field of coverage. 

The system must 

consist of enough lights to illuminate 
the vital areas around the rotorcraft, 
considering the physical configuration 
and flight characteristics of the rotor-
craft. The field of coverage must ex-
tend in each direction within at least 
30 degrees below the horizontal plane of 
the rotorcraft, except that there may 
be solid angles of obstructed visibility 
totaling not more than 0.5 steradians. 

(c) 

Flashing characteristics. 

The ar-

rangement of the system, that is, the 
number of light sources, beam width, 
speed of rotation, and other character-
istics, must give an effective flash fre-
quency of not less than 40, nor more 
than 100, cycles per minute. The effec-
tive flash frequency is the frequency at 
which the rotorcraft’s complete anti-
collision light system is observed from 
a distance, and applies to each sector 
of light including any overlaps that 
exist when the system consists of more 
than one light source. In overlaps, 
flash frequencies may exceed 100, but 
not 180, cycles per minute. 

(d) 

Color. 

Each anticollision light 

must be aviation red and must meet 
the applicable requirements of § 27.1397. 

(e) 

Light intensity. 

The minimum 

light intensities in any vertical plane, 
measured with the red filter (if used) 
and expressed in terms of ‘‘effective’’ 
intensities, must meet the require-
ments of paragraph (f) of this section. 
The following relation must be as-
sumed: 

I

I t dt

t

t

e

t

t

=

+

(

)

( )

.

1

2

0 2

2

1

where: 

I

e

= effective intensity (candles). 

I(t) 

= instantaneous intensity as a function 

of time. 

t

2

¥

t

1

= flash time interval (seconds). 

Normally, the maximum value of effective 
intensity is obtained when 

t

2

and 

t

1

are cho-

sen so that the effective intensity is equal to 
the instantaneous intensity at 

t

2

and 

t

1

(f) 

Minimum effective intensities for 

anticollision light. 

Each anticollision 

light effective intensity must equal or 
exceed the applicable values in the fol-
lowing table: 

Angle above or below the horizontal plane 

Effective 

intensity 

(candles) 

0

° 

to 5

°

................................................................

150 

5

° 

to 10

°

..............................................................

90 

10

° 

to 20

°

............................................................

30 

20

° 

to 30

°

............................................................

15 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–6, 36 FR 12972, July 10, 
1971; Amdt. 27–10, 41 FR 5290, Feb. 5, 1976] 

S

AFETY

E

QUIPMENT

 

§ 27.1411

General. 

(a) Required safety equipment to be 

used by the crew in an emergency, such 
as flares and automatic liferaft re-
leases, must be readily accessible. 

(b) Stowage provisions for required 

safety equipment must be furnished 
and must— 

(1) Be arranged so that the equip-

ment is directly accessible and its loca-
tion is obvious; and 

(2) Protect the safety equipment 

from damage caused by being subjected 
to the inertia loads specified in § 27.561. 

[Doc. No. 5074, 29 FR 15695, Nov. 24, 1964, as 
amended by Amdt. 27–11, 41 FR 55470, Dec. 20, 
1976] 

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