- General
If certification for night operation is requested, the rotorcraft must have an anti-collision light system that:
- Consists of one or more approved anti-collision lights located so that their emitted light will not impair the crew’s vision or detract from the conspicuity of the position lights; and
- Meets the requirements of subparagraphs (b) to (f)
- 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 rotorcraft. The field of coverage must
extend in each direction within at least 30° above
and 30° below the horizontal plane of the
rotorcraft, except that there may be solid angles
of obstructed visibility totalling not more than
0.5 steradians.
- Flashing characteristics
The
arrangement of the system, that is, the number of
light sources, beam width, speed of rotation, and
other characteristics, must give an effective flash
frequency of not less than 40, nor more than 100,
cycles per minute. The effective 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.
- Colour
Each anti-collision light must
be aviation red and must meet the applicable
requirements of CS 27.1397.
- 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
requirements of sub-paragraph (f). The following
relation must be assumed:
$$I_e = \frac{\int_{t1}^{t2}}{0.2 + (t_2 - t_1)}$$
where:
- Ie
- effective intensity, candles
- I(t)
- instantaneous intensity as a function of time
- t2 - t1
- flash time interval (seconds); Normally, the maximum value of effective
intensity is obtained when t2 and t1 are chosen so
that the effective intensity is equal to the
instantaneous intensity at t2 and t1.
- Minimum effective intensities for anticollision
light
Each anti-collision light effective
intensity must equal or exceed the applicable
values in the following table:
Angle above or below
the horizontal plane |
Effective intensity
(candelas) |
| 0 ° to 5 ° |
150 |
| 5 ° to 10 ° |
90 |
| 10 ° to 20 ° |
30 |
| 20 ° to 30 ° |
15 |