867 

Federal Aviation Administration, DOT 

§ 33.76 

(3) The impact to the front of the en-

gine from the large single bird, the sin-
gle largest medium bird which can 
enter the inlet, and the large flocking 
bird must be evaluated. Applicants 
must show that the associated compo-
nents when struck under the condi-
tions prescribed in paragraphs (b), (c) 
or (d) of this section, as applicable, will 
not affect the engine to the extent that 
the engine cannot comply with the re-
quirements of paragraphs (b)(3), (c)(6) 
and (d)(4) of this section. 

(4) For an engine that incorporates 

an inlet protection device, compliance 
with this section shall be established 
with the device functioning. The en-
gine approval will be endorsed to show 
that compliance with the requirements 
has been established with the device 
functioning. 

(5) Objects that are accepted by the 

Administrator may be substituted for 
birds when conducting the bird inges-
tion tests required by paragraphs (b), 
(c) and (d) of this section. 

(6) If compliance with the require-

ments of this section is not estab-
lished, the engine type certification 
documentation will show that the en-
gine shall be limited to aircraft instal-
lations in which it is shown that a bird 
cannot strike the engine, or be in-
gested into the engine, or adversely re-
strict airflow into the engine. 

(b) 

Large single bird.Compliance with 

the large bird ingestion requirements 
shall be in accordance with the fol-
lowing: 

(1) The large bird ingestion test shall 

be conducted using one bird of a weight 
determined from Table 1 aimed at the 
most critical exposed location on the 
first stage rotor blades and ingested at 
a bird speed of 200-knots for engines to 
be installed on airplanes, or the max-
imum airspeed for normal rotorcraft 
flight operations for engines to be in-
stalled on rotorcraft. 

(2) Power lever movement is not per-

mitted within 15 seconds following in-
gestion of the large bird. 

(3) Ingestion of a single large bird 

tested under the conditions prescribed 
in this section may not result in any 
condition described in § 33.75(g)(2) of 
this part. 

(4) Compliance with the large bird in-

gestion requirements of this paragraph 

may be shown by demonstrating that 
the requirements of § 33.94(a) constitute 
a more severe demonstration of blade 
containment and rotor unbalance than 
the requirements of this paragraph. 

T

ABLE

1 

TO

§ 33.76—L

ARGE

B

IRD

W

EIGHT

 

R

EQUIREMENTS

 

Engine Inlet Throat Area 

(A)—Square-meters (square- 

inches) 

Bird weight kg. (lb.) 

1.35 (2,092)>A .......................

1.85 (4.07) minimum, unless 

a smaller bird is deter-
mined to be a more severe 
demonstration. 

1.35 (2,092)

≤

A<3.90 (6,045)

2.75 (6.05) 

3.90 (6,045)

≤

A .......................

3.65 (8.03) 

(c) 

Small and medium flocking bird. 

Compliance with the small and me-
dium bird ingestion requirements shall 
be in accordance with the following: 

(1) Analysis or component test, or 

both, acceptable to the Administrator, 
shall be conducted to determine the 
critical ingestion parameters affecting 
power loss and damage. Critical inges-
tion parameters shall include, but are 
not limited to, the effects of bird speed, 
critical target location, and first stage 
rotor speed. The critical bird ingestion 
speed should reflect the most critical 
condition within the range of airspeeds 
used for normal flight operations up to 
1,500 feet above ground level, but not 
less than V

1

minimum for airplanes. 

(2) Medium bird engine tests shall be 

conducted so as to simulate a flock en-
counter, and will use the bird weights 
and quantities specified in Table 2. 
When only one bird is specified, that 
bird will be aimed at the engine core 
primary flow path; the other critical 
locations on the engine face area must 
be addressed, as necessary, by appro-
priate tests or analysis, or both. When 
two or more birds are specified in Table 
2, the largest of those birds must be 
aimed at the engine core primary flow 
path, and a second bird must be aimed 
at the most critical exposed location 
on the first stage rotor blades. Any re-
maining birds must be evenly distrib-
uted over the engine face area. 

(3) In addition, except for rotorcraft 

engines, it must also be substantiated 
by appropriate tests or analysis or 
both, that when the full fan assembly 
is subjected to the ingestion of the 
quantity and weights of bird from 

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