527 

Federal Aviation Administration, DOT 

§ 25.1703 

the form of guidance material, includ-
ing any relevant limitations or infor-
mation. 

(5) An explanation of significant or 

unusual flight or ground handling char-
acteristics of the airplane. 

(6) Corrections to indicated values of 

airspeed, altitude, and outside air tem-
perature. 

(7) An explanation of operational 

landing runway length factors included 
in the presentation of the landing dis-
tance, if appropriate. 

[Doc. No. 2000–8511, 66 FR 34024, June 26, 2001, 
as amended by Amdt. 25–108, 67 FR 70828, 
Nov. 26, 2002] 

Subpart H—Electrical Wiring 

Interconnection Systems (EWIS) 

S

OURCE

: Docket No. FAA–2004–18379, 72 FR 

63406, Nov. 8, 2007, unless otherwise noted. 

§ 25.1701

Definition. 

(a) As used in this chapter, electrical 

wiring interconnection system (EWIS) 
means any wire, wiring device, or com-
bination of these, including termi-
nation devices, installed in any area of 
the airplane for the purpose of trans-
mitting electrical energy, including 
data and signals, between two or more 
intended termination points. This in-
cludes: 

(1) Wires and cables. 
(2) Bus bars. 
(3) The termination point on elec-

trical devices, including those on re-
lays, interrupters, switches, 
contactors, terminal blocks and circuit 
breakers, and other circuit protection 
devices. 

(4) Connectors, including feed- 

through connectors. 

(5) Connector accessories. 
(6) Electrical grounding and bonding 

devices and their associated connec-
tions. 

(7) Electrical splices. 
(8) Materials used to provide addi-

tional protection for wires, including 
wire insulation, wire sleeving, and con-
duits that have electrical termination 
for the purpose of bonding. 

(9) Shields or braids. 
(10) Clamps and other devices used to 

route and support the wire bundle. 

(11) Cable tie devices. 

(12) Labels or other means of identi-

fication. 

(13) Pressure seals. 
(14) EWIS components inside shelves, 

panels, racks, junction boxes, distribu-
tion panels, and back-planes of equip-
ment racks, including, but not limited 
to, circuit board back-planes, wire in-
tegration units, and external wiring of 
equipment. 

(b) Except for the equipment indi-

cated in paragraph (a)(14) of this sec-
tion, EWIS components inside the fol-
lowing equipment, and the external 
connectors that are part of that equip-
ment, are excluded from the definition 
in paragraph (a) of this section: 

(1) Electrical equipment or avionics 

that are qualified to environmental 
conditions and testing procedures when 
those conditions and procedures are— 

(i) Appropriate for the intended func-

tion and operating environment, and 

(ii) Acceptable to the FAA. 
(2) Portable electrical devices that 

are not part of the type design of the 
airplane. This includes personal enter-
tainment devices and laptop com-
puters. 

(3) Fiber optics. 

§ 25.1703

Function and installation: 

EWIS. 

(a) Each EWIS component installed 

in any area of the aircraft must: 

(1) Be of a kind and design appro-

priate to its intended function. 

(2) Be installed according to limita-

tions specified for the EWIS compo-
nents. 

(3) Perform the function for which it 

was intended without degrading the 
airworthiness of the airplane. 

(4) Be designed and installed in a way 

that will minimize mechanical strain. 

(b) Selection of wires must take into 

account known characteristics of the 
wire in relation to each installation 
and application to minimize the risk of 
wire damage, including any arc track-
ing phenomena. 

(c) The design and installation of the 

main power cables (including generator 
cables) in the fuselage must allow for a 
reasonable degree of deformation and 
stretching without failure. 

(d) EWIS components located in 

areas of known moisture accumulation 

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