FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 11. Aircraft Electrical Systems | 3. Inspection of Equipment Installation | 11-34. Static Electrical Power Converters
9/27/01
AC 43.13-1B CHG 1
SECTION 3. INSPECTION OF EQUIPMENT INSTALLATION
11-30. GENERAL. When installing equip-
ment which consumes electrical power in an
aircraft, it should be determined that the total
electrical load can be safely controlled or man-
aged within the rated limits of the affected
components of the aircraft’s electrical power
supply system. Addition of most electrical
utilization equipment is a major alteration and
requires appropriate FAA approval. The elec-
trical load analysis must be prepared in general
accordance with good engineering practices.
Additionally, an addendum to the flight man-
ual is generally required.
11-31. INSTALLATION CLEARANCE
PROVISIONS. All electrical equipment
should be installed so that inspection and
maintenance may be performed and that the in-
stallation does not interfere with other systems,
such as engine or flight controls.
11-32. WIRES, WIRE BUNDLES, AND
CIRCUIT PROTECTIVE DEVICES. Be-
fore any aircraft electrical load is increased, the
new total electrical load (previous maximum
load plus added load) must be checked to de-
termine if the design levels are being ex-
ceeded. Where necessary, wires, wire bundles,
and circuit protective devices having the cor-
rect ratings should be added or replaced.
11-33. ALTERNATOR DIODES. Alter-
nators employ diodes for the purpose of con-
verting the alternating current to direct current.
These diodes are solid-state electronic devices
and are easily damaged by rough handling,
abuse, over heating, or reversing the battery
connections. A voltage surge in the line, if it
exceeds the design value, may destroy the di-
ode. The best protection against diode destruction
by voltage surges is to make certain that the bat-
tery is never disconnected from the aircraft's
electrical system when the alternator is in op-
eration. The battery acts as a large capacitor
and tends to damp out voltage surges. The
battery must never be connected with reversed
polarity as this may subject the diodes to a
forward bias condition, allowing very high cur-
rent conduction that will generally destroy
them instantly.
11-34. STATIC ELECTRICAL POWER
CONVERTERS. Static power converters em-
ploy solid-state devices to convert the aircraft’s
primary electrical source voltage to a different
voltage or frequency for the operation of radio
and electronic equipment. They contain no
moving parts (with the exception of a cooling
fan on some models) and are relatively main-
tenance free. Various types are available for ac
to dc or dc to ac conversion.
a. Location of static converters should
be carefully chosen to ensure adequate venti-
lation for cooling purposes. Heat-radiating fins
should be kept clean of dirt and other foreign
matter that may impair their cooling proper-
ties.
b. Static power converters often emit un-
acceptable levels of EMI that may disrupt
communication equipment and navigation in-
struments. Properly shielded connectors, ter-
minal blocks, and wires may be required, with
all shields well grounded to the airframe.
CAUTION: Do not load convert-
ers beyond their rated capacity.
Par 11-30
Page 11-11