Textbook page 169, 171
The function of the aircraft electrical system is to
generate, regulate and distribute electrical power
throughout the aircraft.
More and More Electricity
AC (Advisory Circular)
43.13-1B
CHAPTER 11. AIRCRAFT ELECTRICAL SYSTEMS
SECTION 20. ELECTRICAL AND ELECTRONIC
SYMBOLS
Alternating Current
DC Alternators
Electrical Units of Measure
Voltage (pressure) unit of measure is the Volt
Current (flow) unit of measure is the Ampere
(amp)
Resistance (friction) unit of measure is the Ohm
Power (force) unit of measure is the Watt
Block Diagrams
A block diagram is used as an aid for troubleshooting complex
electrical and electronic systems. A block diagram consists
of individual blocks that represent several components, such as a
printed circuit board or some other type of replaceable module.
Pictorial Diagrams
In a pictorial diagram, pictures of components are used instead
of the conventional electrical symbols found in schematic
diagrams. A pictorial diagram helps the maintenance technician
visualize the operation of a system.
Schematic Diagrams
A schematic diagram is used to illustrate a principle of operation,
and therefore does not show parts as they actually appear or
function.
Bus
In electrical power distribution, a busbar is a strip or bar that conducts
electricity within an electrical apparatus. Its main purpose is to conduct
electricity, not to function as a structural member.
A distribution point in an aircraft electrical system to which the battery and
the generator(s) are connected and from which the electrical loads derive
their power.
In computer architecture, a bus is a subsystem that transfers data between
components inside a computer, or between computers
The word “bus” comes from a shortened version of “omnibus”, the Latin word
that roughly means “all in one
Switch
A device for turning on or off or directing an
electric current or for making or breaking a
circuit.
Textbook page 173
Circuit Breaker
An automatic switch that stops the flow of
electric current in a suddenly overloaded or
otherwise abnormally stressed electric circuit.
Fuse
A current limiting device.
Coaxial or Coax Cable
The term coaxial comes from the inner conductor and the outer
shield sharing a geometric axis.
Coaxial cable is used as a transmission line for radio frequency
signals. Its applications include feed lines connecting radio
transmitters and receivers with their antennas.
Wed 11-28
Coaxial or Coax Cable
The inner and outer conductors are separated by
an insulating layer known as dielectric.
Choice of materials and dimensions determines
the cable's electrical properties, including
attenuation at various frequencies.
Dielectric
The ideal dielectric is air however air would not
hold the center conductor in place and that is
one of the important requirements of the
dielectric.
A foam material similar to Styrofoam is used to
provide the mechanical properties needed and
approximate the electrical properties of air.
Shielding
Prevents other signals from entering the
cable such as pagers, cell phones,
transmitters etc.
Prevents leakage of cable signals out of the
cable.
Coaxial Cables typically have the following construction:
Metallic center conductor
Layers of Dielectric or insulating Material
A shield
Foil
Wire mesh
A protective jacket
Coax Cable AC 43
Never kink coaxial cable.
Never drop anything on coaxial cable.
Never step on coaxial cable.
Never bend coaxial cable sharply.
Never loop coaxial cable tighter than the
allowable bend radius.
Never pull on coaxial cable except in a straight
line.
Coax Bend Radius
Textbook page 228
Instruments Required by FAR 91.205
For VFR flight during the day
(1) Airspeed indicator.
(2) Altimeter.
(3) Magnetic direction indicator.
(4) Tachometer for each engine.
(5) Oil pressure gauge for each engine using pressure system.
(6) Temperature gauge for each liquid-cooled engine.
(7) Oil temperature gauge for each air-cooled engine.
(8) Manifold pressure gauge for each altitude engine.
(9) Fuel gauge indicating the quantity of fuel in each tank.
(10) Landing gear position indicator, if the aircraft has a
retractable landing gear.
Textbook Chapter 21 Installing
page 156, 160
Federal Aviation Regulations
91.207 Emergency locator transmitters.
91.215 ATC transponder and altitude reporting equipment.
91.219 Altitude alerting system or device
91.221 Traffic alert and collision avoidance system equipment .
91.223 Terrain awareness and warning system.
91.225 Automatic Dependent Surveillance-Broadcast (ADS–B) Out
equipment.
ESD Electro Static Discharge
ESD
ESD
Packing Material
Voltage– Voltage symbol is traditionally “E” for
ElectroMotive Force (EMF)
Current– Current symbol is traditionally “I” for
Intensity
Resistance– Resistance symbol is “R” in
equations and the Greek symbol omega Ω for
values
Power – Power symbol may be “P”ower or
“W”atts
Ohms Law
AC (Advisory Circular)
43.13-1B
CHAPTER 11. AIRCRAFT ELECTRICAL SYSTEMS
SECTION 20. ELECTRICAL AND ELECTRONIC
SYMBOLS