868
14 CFR Ch. I (1–1–14 Edition)
§ 33.76
Table 3, aimed at the fan assembly’s
most critical location outboard of the
primary core flowpath, and in accord-
ance with the applicable test condi-
tions of this paragraph, that the engine
can comply with the acceptance cri-
teria of this paragraph.
(4) A small bird ingestion test is not
required if the prescribed number of
medium birds pass into the engine
rotor blades during the medium bird
test.
(5) Small bird ingestion tests shall be
conducted so as to simulate a flock en-
counter using one 85 gram (0.187 lb.)
bird for each 0.032 square-meter (49.6
square-inches) of inlet area, or fraction
thereof, up to a maximum of 16 birds.
The birds will be aimed so as to ac-
count for any critical exposed locations
on the first stage rotor blades, with
any remaining birds evenly distributed
over the engine face area.
(6) Ingestion of small and medium
birds tested under the conditions pre-
scribed in this paragraph may not
cause any of the following:
(i) More than a sustained 25-percent
power or thrust loss;
(ii) The engine to be shut down dur-
ing the required run-on demonstration
prescribed in paragraphs (c)(7) or (c)(8)
of this section;
(iii) The conditions defined in para-
graph (b)(3) of this section.
(iv) Unacceptable deterioration of en-
gine handling characteristics.
(7) Except for rotorcraft engines, the
following test schedule shall be used:
(i) Ingestion so as to simulate a flock
encounter, with approximately 1 sec-
ond elapsed time from the moment of
the first bird ingestion to the last.
(ii) Followed by 2 minutes without
power lever movement after the inges-
tion.
(iii) Followed by 3 minutes at 75-per-
cent of the test condition.
(iv) Followed by 6 minutes at 60-per-
cent of the test condition.
(v) Followed by 6 minutes at 40-per-
cent of the test condition.
(vi) Followed by 1 minute at ap-
proach idle.
(vii) Followed by 2 minutes at 75-per-
cent of the test condition.
(viii) Followed by stabilizing at idle
and engine shut down.
(ix) The durations specified are times
at the defined conditions with the
power being changed between each con-
dition in less than 10 seconds.
(8) For rotorcraft engines, the fol-
lowing test schedule shall be used:
(i) Ingestion so as to simulate a flock
encounter within approximately 1 sec-
ond elapsed time between the first in-
gestion and the last.
(ii) Followed by 3 minutes at 75-per-
cent of the test condition.
(iii) Followed by 90 seconds at de-
scent flight idle.
(iv) Followed by 30 seconds at 75-per-
cent of the test condition.
(v) Followed by stabilizing at idle
and engine shut down.
(vi) The durations specified are times
at the defined conditions with the
power being changed between each con-
dition in less than 10 seconds.
(9) Engines intended for use in multi-
engine rotorcraft are not required to
comply with the medium bird ingestion
portion of this section, providing that
the appropriate type certificate docu-
mentation is so endorsed.
(10) If any engine operating limit(s) is
exceeded during the initial 2 minutes
without power lever movement, as pro-
vided by paragraph (c)(7)(ii) of this sec-
tion, then it shall be established that
the limit exceedence will not result in
an unsafe condition.
T
ABLE
2
TO
§ 33.76—M
EDIUM
F
LOCKING
B
IRD
W
EIGHT AND
Q
UANTITY
R
EQUIREMENTS
Engine Inlet Throat Area (A)—
Square-meters (square-inches)
Bird
quantity
Bird weight
kg. (lb.)
0.05 (77.5)>A ...................................
none .....
0.05 (77.5)
≤
A <0.10 (155) ...............
1 ...........
0.35 (0.77)
0.10 (155)
≤
A <0.20 (310) ................
1 ...........
0.45 (0.99)
0.20 (310)
≤
A <0.40 (620) ................
2 ...........
0.45 (0.99)
0.40 (620)
≤
A <0.60 (930) ................
2 ...........
0.70 (1.54)
0.60 (930)
≤
A <1.00 (1,550) .............
3 ...........
0.70 (1.54)
1.00 (1,550)
≤
A <1.35 (2,092) ..........
4 ...........
0.70 (1.54)
1.35 (2,092)
≤
A <1.70 (2,635) ..........
1 ...........
1.15 (2.53)
plus 3 ...
0.70 (1.54)
1.70 (2,635)
≤
A <2.10 (3,255) ..........
1 ...........
1.15 (2.53)
plus 4 ...
0.70 (1.54)
2.10 (3,255)
≤
A <2.50 (3,875) ..........
1 ...........
1.15 (2.53)
plus 5 ...
0.70 (1.54)
2.50 (3,875)
≤
A <3.90 (6045) ...........
1 ...........
1.15 (2.53)
plus 6 ...
0.70 (1.54)
3.90 (6045)
≤
A <4.50 (6975) ............
3 ...........
1.15 (2.53)
4.50 (6975)
≤
A ..................................
4 ...........
1.15 (2.53)
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