373 

Federal Aviation Administration, DOT 

§ 25.1711 

adequate physical separation from hy-
draulic lines and other hydraulic sys-
tem components, so that: 

(1) An EWIS component failure will 

not create a hazardous condition. 

(2) Any hydraulic fluid leakage onto 

EWIS components will not create a 
hazardous condition. 

(g) Except to the extent necessary to 

provide electrical connection to the ox-
ygen systems components, EWIS must 
be designed and installed with ade-
quate physical separation from oxygen 
lines and other oxygen system compo-
nents, so that an EWIS component fail-
ure will not create a hazardous condi-
tion. 

(h) Except to the extent necessary to 

provide electrical connection to the 
water/waste systems components, 
EWIS must be designed and installed 
with adequate physical separation from 
water/waste lines and other water/ 
waste system components, so that: 

(1) An EWIS component failure will 

not create a hazardous condition. 

(2) Any water/waste leakage onto 

EWIS components will not create a 
hazardous condition. 

(i) EWIS must be designed and in-

stalled with adequate physical separa-
tion between the EWIS and flight or 
other mechanical control systems ca-
bles and associated system compo-
nents, so that: 

(1) Chafing, jamming, or other inter-

ference are prevented. 

(2) An EWIS component failure will 

not create a hazardous condition. 

(3) Failure of any flight or other me-

chanical control systems cables or sys-
tems components will not damage the 
EWIS and create a hazardous condi-
tion. 

(j) EWIS must be designed and in-

stalled with adequate physical separa-
tion between the EWIS components 
and heated equipment, hot air ducts, 
and lines, so that: 

(1) An EWIS component failure will 

not create a hazardous condition. 

(2) Any hot air leakage or heat gen-

erated onto EWIS components will not 
create a hazardous condition. 

(k) For systems for which redun-

dancy is required, by certification 
rules, by operating rules, or as a result 
of the assessment required by § 25.1709, 
EWIS components associated with 

those systems must be designed and in-
stalled with adequate physical separa-
tion. 

(l) Each EWIS must be designed and 

installed so there is adequate physical 
separation between it and other air-
craft components and aircraft struc-
ture, and so that the EWIS is protected 
from sharp edges and corners, to mini-
mize potential for abrasion/chafing, vi-
bration damage, and other types of me-
chanical damage. 

§ 25.1709

System safety: EWIS. 

Each EWIS must be designed and in-

stalled so that: 

(a) Each catastrophic failure condi-

tion— 

(1) Is extremely improbable; and 
(2) Does not result from a single fail-

ure. 

(b) Each hazardous failure condition 

is extremely remote. 

§ 25.1711

Component identification: 

EWIS. 

(a) EWIS components must be labeled 

or otherwise identified using a con-
sistent method that facilitates identi-
fication of the EWIS component, its 
function, and its design limitations, if 
any. 

(b) For systems for which redundancy 

is required, by certification rules, by 
operating rules, or as a result of the as-
sessment required by § 25.1709, EWIS 
components associated with those sys-
tems must be specifically identified 
with component part number, function, 
and separation requirement for bun-
dles. 

(1) The identification must be placed 

along the wire, cable, or wire bundle at 
appropriate intervals and in areas of 
the airplane where it is readily visible 
to maintenance, repair, or alteration 
personnel. 

(2) If an EWIS component cannot be 

marked physically, then other means 
of identification must be provided. 

(c) The identifying markings re-

quired by paragraphs (a) and (b) of this 
section must remain legible through-
out the expected service life of the 
EWIS component. 

(d) The means used for identifying 

each EWIS component as required by 
this section must not have an adverse 

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