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14 CFR Ch. I (1–1–19 Edition) 

§ 33.76 

items that could fail in a latent man-
ner. When necessary to prevent haz-
ardous engine effects, these mainte-
nance actions and intervals must be 
published in the instructions for con-
tinued airworthiness required under 
§ 33.4 of this part. Additionally, if er-
rors in maintenance of the engine, in-
cluding the control system, could lead 
to hazardous engine effects, the appro-
priate procedures must be included in 
the relevant engine manuals. 

(2) Verification of the satisfactory 

functioning of safety or other devices 
at pre-flight or other stated periods. 
The details of this satisfactory func-
tioning must be published in the appro-
priate manual. 

(3) The provisions of specific instru-

mentation not otherwise required. 

(4) Flight crew actions to be specified 

in the operating instructions estab-
lished under § 33.5. 

(f) If applicable, the safety analysis 

must also include, but not be limited 
to, investigation of the following: 

(1) Indicating equipment; 
(2) Manual and automatic controls; 
(3) Compressor bleed systems; 
(4) Refrigerant injection systems; 
(5) Gas temperature control systems; 
(6) Engine speed, power, or thrust 

governors and fuel control systems; 

(7) Engine overspeed, overtempera-

ture, or topping limiters; 

(8) Propeller control systems; and 
(9) Engine or propeller thrust rever-

sal systems. 

(g) Unless otherwise approved by the 

FAA and stated in the safety analysis, 
for compliance with part 33, the fol-
lowing failure definitions apply to the 

(1) An engine failure in which the 

only consequence is partial or com-
plete loss of thrust or power (and asso-
ciated engine services) from the engine 
will be regarded as a minor engine ef-

(2) The following effects will be re-

garded as hazardous engine effects: 

(i) Non-containment of high-energy 


(ii) Concentration of toxic products 

in the engine bleed air intended for the 
cabin sufficient to incapacitate crew or 

(iii) Significant thrust in the oppo-

site direction to that commanded by 
the pilot; 

(iv) Uncontrolled fire; 
(v) Failure of the engine mount sys-

tem leading to inadvertent engine sep-

(vi) Release of the propeller by the 

engine, if applicable; and 

(vii) Complete inability to shut the 

engine down. 

(3) An effect whose severity falls be-

tween those effects covered in para-
graphs (g)(1) and (g)(2) of this section 
will be regarded as a major engine ef-

[Amdt. 33–24, 72 FR 50867, Sept. 4, 2007] 

§ 33.76

Bird ingestion. 



Compliance with para-

graphs (b), (c), and (d) of this section 
shall be in accordance with the fol-

(1) Except as specified in paragraph 

(d) of this section, all ingestion tests 
must be conducted with the engine sta-
bilized at no less than 100-percent take-
off power or thrust, for test day ambi-
ent conditions prior to the ingestion. 
In addition, the demonstration of com-
pliance must account for engine oper-
ation at sea level takeoff conditions on 
the hottest day that a minimum engine 
can achieve maximum rated takeoff 
thrust or power. 

(2) The engine inlet throat area as 

used in this section to determine the 
bird quantity and weights will be es-
tablished by the applicant and identi-
fied as a limitation in the installation 
instructions required under § 33.5. 

(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 

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