661 

Federal Aviation Administration, DOT 

§ 29.1353 

and do not cause a smoke or fire haz-
ard; 

(5) There are means accessible in 

flight to appropriate crewmembers for 
the individual and collective dis-
connection of the electrical power 
sources from the main bus; and 

(6) There are means to indicate to ap-

propriate crewmembers the generating 
system quantities essential for the safe 
operation of the system, such as the 
voltage and current supplied by each 
generator. 

(c) 

External power. 

If provisions are 

made for connecting external power to 
the rotorcraft, and that external power 
can be electrically connected to equip-
ment other than that used for engine 
starting, means must be provided to 
ensure that no external power supply 
having a reverse polarity, or a reverse 
phase sequence, can supply power to 
the rotorcraft’s electrical system. 

(d) Operation with the normal elec-

trical power generating system inoper-
ative. 

(1) It must be shown by analysis, 

tests, or both, that the rotorcraft can 
be operated safely in VFR conditions 
for a period of not less than 5 minutes, 
with the normal electrical power gen-
erating system (electrical power 
sources excluding the battery) inoper-
ative, with critical type fuel (from the 
standpoint of flameout and restart ca-
pability), and with the rotorcraft ini-
tially at the maximum certificated al-
titude. Parts of the electrical system 
may remain on if— 

(i) A single malfunction, including a 

wire bundle or junction box fire, can-
not result in loss of the part turned off 
and the part turned on; 

(ii) The parts turned on are elec-

trically and mechanically isolated 
from the parts turned off; and 

(2) Additional requirements for Cat-

egory A Rotorcraft. 

(i) Unless it can be shown that the 

loss of the normal electrical power gen-
erating system is extremely improb-
able, an emergency electrical power 
system, independent of the normal 
electrical power generating system, 
must be provided, with sufficient ca-
pacity to power all systems necessary 
for continued safe flight and landing. 

(ii) Failures, including junction box, 

control panel, or wire bundle fires, 

which would result in the loss of the 
normal and emergency systems, must 
be shown to be extremely improbable. 

(iii) Systems necessary for imme-

diate safety must continue to operate 
following the loss of the normal elec-
trical power generating system, with-
out the need for flight crew action. 

(Secs. 313(a), 601, 603, 604, and 605 of the Fed-
eral Aviation Act of 1958 (49 U.S.C. 1354(a), 
1421, 1423, 1424, and 1425); and sec. 6(c), Dept. 
of Transportation Act (49 U.S.C. 1655(c))) 

[Doc. No. 5084, 29 FR 16150, Dec. 3, 1964, as 
amended by Amdt. 29–14, 42 FR 36973, July 18, 
1977; Amdt. 29–40, 61 FR 21908, May 10, 1996; 
Amdt. 29–42, 63 FR 43285, Aug. 12, 1998] 

§ 29.1353

Electrical equipment and in-

stallations. 

(a) Electrical equipment, controls, 

and wiring must be installed so that 
operation of any one unit or system of 
units will not adversely affect the si-
multaneous operation of any other 
electrical unit or system essential to 
safe operation. 

(b) Cables must be grouped, routed, 

and spaced so that damage to essential 
circuits will be minimized if there are 
faults in heavy current-carrying ca-
bles. 

(c) Storage batteries must be de-

signed and installed as follows: 

(1) Safe cell temperatures and pres-

sures must be maintained during any 
probable charging and discharging con-
dition. No uncontrolled increase in cell 
temperature may result when the bat-
tery is recharged (after previous com-
plete discharge)— 

(i) At maximum regulated voltage or 

power; 

(ii) During a flight of maximum dura-

tion; and 

(iii) Under the most adverse cooling 

condition likely in service. 

(2) Compliance with paragraph (a)(1) 

of this section must be shown by test 
unless experience with similar bat-
teries and installations has shown that 
maintaining safe cell temperatures and 
pressures presents no problem. 

(3) No explosive or toxic gases emit-

ted by any battery in normal oper-
ation, or as the result of any probable 
malfunction in the charging system or 
battery installation, may accumulate 
in hazardous quantities within the 
rotorcraft. 

VerDate Sep<11>2014 

12:50 Apr 30, 2019

Jkt 247046

PO 00000

Frm 00671

Fmt 8010

Sfmt 8010

Y:\SGML\247046.XXX

247046

spaschal on DSK3GDR082PROD with CFR