310 

14 CFR Ch. I (1–1–24 Edition) 

§ 25.901 

as not to endanger the airplane, per-
sonnel, or operation of the installed 
electrical/electronic systems. 

[Amdt. 25–123, 72 FR 63405, Nov. 8, 2007] 

Subpart E—Powerplant 

G

ENERAL

 

§ 25.901

Installation. 

(a) For the purpose of this part, the 

airplane powerplant installation in-
cludes each component that— 

(1) Is necessary for propulsion; 
(2) Affects the control of the major 

propulsive units; or 

(3) Affects the safety of the major 

propulsive units between normal in-
spections or overhauls. 

(b) For each powerplant— 
(1) The installation must comply 

with— 

(i) The installation instructions pro-

vided under §§ 33.5 and 35.3 of this chap-
ter; and 

(ii) The applicable provisions of this 

subpart; 

(2) The components of the installa-

tion must be constructed, arranged, 
and installed so as to ensure their con-
tinued safe operation between normal 
inspections or overhauls; 

(3) The installation must be acces-

sible for necessary inspections and 
maintenance; and 

(4) The major components of the in-

stallation must be electrically bonded 
to the other parts of the airplane. 

(c) For each powerplant and auxiliary 

power unit installation, it must be es-
tablished that no single failure or mal-
function or probable combination of 
failures will jeopardize the safe oper-
ation of the airplane except that the 
failure of structural elements need not 
be considered if the probability of such 
failure is extremely remote. 

(d) Each auxiliary power unit instal-

lation must meet the applicable provi-
sions of this subpart. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–23, 35 FR 5676, Apr. 8, 
1970; Amdt. 25–40, 42 FR 15042, Mar. 17, 1977; 
Amdt. 25–46, 43 FR 50597, Oct. 30, 1978; Amdt. 
25–126, 73 FR 63345, Oct. 24, 2008] 

§ 25.903

Engines. 

(a) 

Engine type certificate. (1) Each en-

gine must have a type certificate and 

must meet the applicable requirements 
of part 34 of this chapter. 

(2) Each turbine engine must comply 

with one of the following: 

(i) Sections 33.76, 33.77 and 33.78 of 

this chapter in effect on December 13, 
2000, or as subsequently amended; or 

(ii) Sections 33.77 and 33.78 of this 

chapter in effect on April 30, 1998, or as 
subsequently amended before Decem-
ber 13, 2000; or 

(iii) Comply with § 33.77 of this chap-

ter in effect on October 31, 1974, or as 
subsequently amended prior to April 
30, 1998, unless that engine’s foreign ob-
ject ingestion service history has re-
sulted in an unsafe condition; or 

(iv) Be shown to have a foreign object 

ingestion service history in similar in-
stallation locations which has not re-
sulted in any unsafe condition. 

N

OTE

: § 33.77 of this chapter in effect on Oc-

tober 31, 1974, was published in 14 CFR parts 
1 to 59, Revised as of January 1, 1975. See 39 
FR 35467, October 1, 1974. 

(3) Each turbine engine must comply 

with one of the following paragraphs: 

(i) Section 33.68 of this chapter in ef-

fect on January 5, 2015, or as subse-
quently amended; or 

(ii) Section 33.68 of this chapter in ef-

fect on March 26, 1984, or as subse-
quently amended before January 5, 
2015, unless that engine’s ice accumula-
tion service history has resulted in an 
unsafe condition; or 

(iii) Section 33.68 of this chapter in 

effect on October 31, 1974, or as subse-
quently amended prior to February 23, 
1984, unless that engine’s ice accumula-
tion service history has resulted in an 
unsafe condition; or 

(iv) Be shown to have an ice accumu-

lation service history in similar instal-
lation locations which has not resulted 
in any unsafe conditions. 

(b) 

Engine isolation. The powerplants 

must be arranged and isolated from 
each other to allow operation, in at 
least one configuration, so that the 
failure or malfunction of any engine, or 
of any system that can affect the en-
gine, will not— 

(1) Prevent the continued safe oper-

ation of the remaining engines; or 

(2) Require immediate action by any 

crewmember for continued safe oper-
ation. 

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