FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 11. Aircraft Electrical Systems | 2. Storage Batteries | 11-22. Installation Practices
9/8/98
AC 43.13-1B
neutralize with a solution of baking
soda and water, and shower or flush
the affected area with water. For the
eyes, use an eye fountain and flush
with an abundance of water. If potas-
sium hydroxide contacts the skin, neu-
tralize with 9 percent acetic acid,
vinegar, or lemon juice and wash with
water. For the eyes, wash with a weak
solution of boric acid or a weak solu-
tion of vinegar and flush with water.
11-21. NOXIOUS FUMES. When charging
rates are excessive, the electrolyte may boil to
the extent that fumes containing droplets of the
electrolyte are emitted through the cell vents.
These fumes from lead-acid batteries may be-
come noxious to the crew members and pas-
sengers; therefore, thoroughly check the vent-
ing system. NiCad batteries will emit gas near
the end of the charging process and during
overcharge. The battery vent system in the air-
craft should have sufficient air flow to prevent
this explosive mixture from accumulating. It
is often advantageous to install a jar in the
battery vent discharge system serviced with an
agent to neutralize the corrosive effect of bat-
tery vapors.
c. Battery Venting. Battery fumes and
gases may cause an explosive mixture or con-
taminated compartments and should be dis-
persed by adequate ventilation. Venting sys-
tems often use ram pressure to flush fresh air
through the battery case or enclosure to a safe
overboard discharge point. The venting sys-
tem pressure differential should always be
positive, and remain between recommended
minimum and maximum values. Line runs
should not permit battery overflow fluids or
condensation to be trapped and prevent free
airflow.
d. Battery Sump Jars. A battery sump
jar installation may be incorporated in the
venting system to dispose of battery electrolyte
overflow. The sump jar should be of adequate
design and the proper neutralizing agent used.
The sump jar must be located only on the dis-
charge side of the battery venting system. (See
figure 11-1.)
11-22. INSTALLATION PRACTICES.
a. External Surface. Clean the external
surface of the battery prior to installation in the
aircraft.
b. Replacing Lead-Acid Batteries.
When replacing lead-acid batteries with NiCad
batteries, a battery temperature or current
monitoring system must be installed. Neu-
tralize the battery box or compartment and
thoroughly flush with water and dry. A flight
manual supplement must also be provided for
the NiCad battery installation. Acid residue
can be detrimental to the proper functioning of
a NiCad battery, as alkaline will be to a lead-
acid battery.
FIGURE 11-1. Battery ventilating systems.
e. Installing Batteries. When installing
batteries in an aircraft, exercise care to prevent
inadvertent shorting of the battery terminals.
Serious damage to the aircraft structure (frame,
skin and other subsystems, avionics, wire, fuel
etc.) can be sustained by the resultant high dis-
charge of electrical energy. This condition
Par 11-20
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