263 

Federal Aviation Administration, DOT 

§ 25.607 

need not be considered. Corrective ac-
tion to be taken by the pilot following 
the incident, such as limiting maneu-
vers, avoiding turbulence, and reducing 
speed, must be considered. If signifi-
cant changes in structural stiffness or 
geometry, or both, follow from a struc-
tural failure or partial failure, the ef-
fect on damage tolerance must be fur-
ther investigated. 

[Amdt. 25–45, 43 FR 46242, Oct. 5, 1978, as 
amended by Amdt. 25–54, 45 FR 60173, Sept. 
11, 1980; Amdt. 25–72, 55 FR 29776, July 20, 
1990; Amdt. 25–86, 61 FR 5222, Feb. 9, 1996; 
Amdt. 25–96, 63 FR 15714, Mar. 31, 1998; 63 FR 
23338, Apr. 28, 1998; Amdt. 25–132, 75 FR 69781, 
Nov. 15, 2010] 

L

IGHTNING

P

ROTECTION

 

§ 25.581

Lightning protection. 

(a) The airplane must be protected 

against catastrophic effects from light-
ning. 

(b) For metallic components, compli-

ance with paragraph (a) of this section 
may be shown by— 

(1) Bonding the components properly 

to the airframe; or 

(2) Designing the components so that 

a strike will not endanger the airplane. 

(c) For nonmetallic components, 

compliance with paragraph (a) of this 
section may be shown by— 

(1) Designing the components to min-

imize the effect of a strike; or 

(2) Incorporating acceptable means of 

diverting the resulting electrical cur-
rent so as not to endanger the airplane. 

[Amdt. 25–23, 35 FR 5674, Apr. 8, 1970] 

Subpart D—Design and 

Construction 

G

ENERAL

 

§ 25.601

General. 

The airplane may not have design 

features or details that experience has 
shown to be hazardous or unreliable. 
The suitability of each questionable 
design detail and part must be estab-
lished by tests. 

§ 25.603

Materials. 

The suitability and durability of ma-

terials used for parts, the failure of 
which could adversely affect safety, 
must— 

(a) Be established on the basis of ex-

perience or tests; 

(b) Conform to approved specifica-

tions (such as industry or military 
specifications, or Technical Standard 
Orders) that ensure their having the 
strength and other properties assumed 
in the design data; and 

(c) Take into account the effects of 

environmental conditions, such as tem-
perature and humidity, expected in 
service. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–38, 41 FR 55466, Dec. 20, 
1976; Amdt. 25–46, 43 FR 50595, Oct. 30, 1978] 

§ 25.605

Fabrication methods. 

(a) The methods of fabrication used 

must produce a consistently sound 
structure. If a fabrication process (such 
as gluing, spot welding, or heat treat-
ing) requires close control to reach this 
objective, the process must be per-
formed under an approved process spec-
ification. 

(b) Each new aircraft fabrication 

method must be substantiated by a 
test program. 

[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as 
amended by Amdt. 25–46, 43 FR 50595, Oct. 30, 
1978] 

§ 25.607

Fasteners. 

(a) Each removable bolt, screw, nut, 

pin, or other removable fastener must 
incorporate two separate locking de-
vices if— 

(1) Its loss could preclude continued 

flight and landing within the design 
limitations of the airplane using nor-
mal pilot skill and strength; or 

(2) Its loss could result in reduction 

in pitch, yaw, or roll control capability 
or response below that required by 
Subpart B of this chapter. 

(b) The fasteners specified in para-

graph (a) of this section and their lock-
ing devices may not be adversely af-
fected by the environmental conditions 
associated with the particular installa-
tion. 

(c) No self-locking nut may be used 

on any bolt subject to rotation in oper-
ation unless a nonfriction locking de-
vice is used in addition to the self-lock-
ing device. 

[Amdt. 25–23, 35 FR 5674, Apr. 8, 1970] 

VerDate Sep<11>2014 

12:50 Apr 30, 2019

Jkt 247046

PO 00000

Frm 00273

Fmt 8010

Sfmt 8010

Y:\SGML\247046.XXX

247046

spaschal on DSK3GDR082PROD with CFR