Aircra& Electrical Systems
Instrument Pricing
• Bendix/King KCS55A HSI
! Starts at $22,188
• Aspen Avionics EFD1000
! Starts at $6,180
• Includes backup baQery
• 2011 Avia>on Consumer declares the HSI dead
! It costs more to repair an HSI than to replace it with
Electrical Systems
• Engine igni>on and controls
! BaQery powered propulsion systems
• Communica>ons
• Naviga>on & Autopilots • Lights
• Flight controls • Landing gear
• Environmental controls • Entertainment system
Part 23 Requirements
• Must be able to furnish the required power at the proper voltage to each load circuit essen>al for safe opera>on
• Must be free from hazards in itself, in its method of opera>on, and in its effects on other parts of the aircra&
• No failure or malfunc>on of any electrical power source may impair the ability of the remaining source to supply load circuits essen>al to safe opera>on
Part 23 Requirements
• Each system must be designed so that essen>al load circuits can be supplied in the event of
reasonably probable faults or open circuits
• There must be at least one generator/alternator if the electrical system supplies power to load circuits essen>al for safe opera>on
• There must be a means of giving immediate warning to the flight crew of a failure of the generator/alternator
Part 23 Requirements
• There must be a master switch installed in the electrical system that allows the electrical power source to be disconnected from the main bus
! The point of disconnec>on must be adjacent to the
Wire Selec>on
• Copper ! BeQer conductor • Aluminum ! Less expensive ! Lighter weight ! Corrosion issues! Easy to nick when removing insula>on ! #6 gage or larger
! Should not be used in areas of severe vibra>on
• Specialty wires (e.g. coax or twisted pair)
! Follow the manufacturer’s recommended
Wire Selec>on
• Selec>ng insula>on type
! Copy what is on the aircra&
• Check for updates
! Follow the manufacturer’s recommended
procedures
• The general rule of thumb for replacing
aluminum electrical cable with copper is that copper of two wire gages smaller (larger
number) may be used to replace aluminum
! e.g. 8 gage aluminum can be replaced with 10 gage
copper
Wire Selec>on
• Wire size selec>on factors
! Allowable power loss
! Permissible voltage drop ! Current carrying capability
Wire Current Carrying Capacity
The American Wire Gauge (AWG) system is used to indicate the size, cross-sectional area, of electrical wire
Sample Problems
• Round up to the larger size
• 28V, 20 A con>nuous for 30’, in a bundle
! #10
• 14V, 200 A for a starter (intermiQent) for 15’, single wire
! #1
• 28V, 50 A con>nuous for 60’, in a bundle
! #4
• What is the maximum length of single #16 wire carrying 28V and 25 A intermiQent
Connectors
• Use only high quality connector
! Lasts longer
! Reduces troubleshoo>ng >me and cost ! Mil spec (AN or MS) are a good start
• Use crimp style connectors when possible
! Soldered connec>ons can “bird cage”
• Female side should be the power side
• Male side should be the ground or no power side
• Use the correct crimper and follow the manufactures recommended procedures
Connectors
• Use moisture-‐proof connectors when it may be exposed to moisture
Terminal Strips
Terminal Strips
• Terminal strip – used to manage wire connec>ons
• O&en use for centralized power and/or ground
! Bus bars
• All terminal studs are anchored against rota>on • AC43.13-‐1B Par 11-‐174(c)
! No more than four terminal lugs or three terminal
lugs and a bus bar should be connected to any one stud. Total number of terminal lugs per stud includes a common bus bar joining adjacent studs. Four
terminal lugs plus a common bus bar thus are not permiQed on one stud.
Terminal Strips
• All stud nuts should be >ghtened
! Even nuts with no connec>ons
• Connec>ons should be firmly held together with two nuts or suitable locking provisions
• Spacers or washers should not be used between the tongues of terminal lugs
• Tightening terminal connec>ons should not deform the terminal lugs or the studs
Terminal Strips
• Terminal lugs should be so posi>oned that
bending of the terminal lug is not required to remove the fastening screw or nut
• Terminal lugs should be so posi>oned that movement of the terminal lugs will tend to >ghten the connec>on.
Wire Terminal Lugs
Wire Terminal Lugs
• The tensile strength of the wire-‐to-‐terminal joint should be at least equivalent to the tensile
strength of the wire itself
• Wire should extend past the barrel and be visible a&er crimping
• The terminal must crimp both the bare wire and the insula>on
• Use ring type terminals to prevent wire disconnect
Wire Terminal Lugs
• Aircra& grade color coding:
! Red -‐ #22 through #18 wire ! Blue -‐ #16 through #14 wire ! Yellow -‐ #12 through #10 wire
Wire Terminal Lugs
X
X
Wire Splices
• Splicing is permiQed on wiring as long as it does not affect the reliability and the
electromechanical characteris>cs of the wiring • No more than one splice in any wire segment
between any two connec>ons or other disconnect points
! Except:
• AQaching to the spare pigtail lead of a poQed connector
• Splicing mul>ple wires to a single wire
• Adjus>ng wire size to fit connector contact crimp barrel
size
Wire Splices
• When several wires in a bundle are to be spliced, the wires should be cut so that the splices are
staggered along the bundle • Use crimp type splice
! Don’t use solder splice
• Splices should not be used within 12 inches of a termina>on device
! Except:
• AQaching to the spare pigtail lead of a poQed connector
• Splicing mul>ple wires to a single wire
• Adjus>ng wire size to fit connector contact crimp barrel
Wire/Cable Labeling
• Wires and cables should be labeled or marked for future maintenance
• Many aircra& have individual wires
manufactured with iden>fica>on markings to match their wiring diagrams
• Wires markings (AC43-‐13-‐1B par 11-‐208):
! At each end and every 15”
• Under 3”, no label
• 3” to 7”, label in center
! Indirect (aQached labels)
• At each end and then every 6’ (feet)
Cable Lacing
• Used secure and organize bundles of wires and cable
! Can secure a bundle with in a bundle
• Don’t use zip >es
! Sharp edges
! Chafes insula>on
! Gets briQle when old
• Use flat lacing: MIL-‐T-‐43435B
! Waxed coa>ng makes it easier to lace
Wire Harnesses
• Video
• An aircra& can have miles of wire
• The wiring is organized into a wiring harness • A wire harness is made up of individual wires
and wire bundles
• New wire harnesses are created using a wiring board or jig
• Electrical upgrades may come with their own harness
Wire Harnesses
• Wire connec>ons may be protected in a junc>on box
! Non-‐vapor-‐>ght boxes must have a drain hole ! Unused holes must be plugged up
! Fire proof junc>on boxes are constructed of stainless
steel (CRES)
Wire Harnesses
• Conduit may be used to route wire
! Protec>ve piping -‐ rigid or flexible
! Protects wire from physical or mechanical damage
• Moving parts
! Supports wire
! Ends of conduit should be flared or have end
coverings to protect wire
! Use bonded clamps, electrically conduc>ve, to
Wire Harnesses
• Conduit
! Should be placed so it is not used as a handhold or
step
! Use installa>on powder (soapstone) to help with
Wire Bundles
• Used to organize wiring
• Wires should be parallel in a bundle
• Should be placed so crew or cargo will not damage
• Should be routed away from where water will collect
• Should be routed over baQery
• Redundant systems should take separate routes • Should be routed above fluid lines
Wire Bundles
• Conduit should be routed as direct as possible • FAA recommends minimizing the number of
wires per bundle to reduce failure risk • Use shielding for:
! Cri>cal connec>ons
• Cartridge actuated fire ex>nguishers, rescue hoist shear,
and emergency jepson devices
Wire Bundles
• Bend radius should be at least 10 >mes the outside bundle diameter
! Individual coax bend radius is 6 >mes the outside
diameter
• Wiring at terminal lugs or connectors should have sufficient slack to allow two re-‐
Wire Mechanical Issues
• Support wire so there is less than 1/2” deflec>on between support points
• Connectors should have strain relief
! Hold wire secure
• Use MS-‐21919 clamps
! Cushioned clamps
! Insulated for wire bundles
! Bonded (connected to ground) used for conduit and
fluid lines
! Close opening with safety wire to help with
Wire Mechanical Issues
• MS-‐21919 clamps
! Interval not to exceed 24”
! Snug fit without pinching wires
• Use grommets
• Use edge grommet
• Seal wire coming through firewall or landing well • Wire sleeving helps protect and organize wires
Clamps
Circuit Protec>on – Part 23
• Protec>ve devices, such as fuses or circuit breakers, must be installed in all electrical circuits other than:
! Main circuits of starter motors used during star>ng
only
! Circuits in which no hazard is presented by their
omission
• A protec>ve device for a circuit essen>al to flight safety may not be used to protect any other
Circuit Protec>on – Part 23
• Each reseQable circuit protec>ve device (“trip free” device in which the tripping mechanism cannot be overridden by the opera>ng control) must be designed so that:
! A manual opera>on is required to restore service
a&er tripping
! If an overload or circuit fault exists, the device will
open the circuit regardless of the posi>on of the opera>ng control
Circuit Protec>on – Part 23
• If the ability to reset a circuit breaker or replace a fuse is essen>al to safety in flight, that circuit breaker or fuse must be so located and
iden>fied that it can be readily reset or replaced in flight
• For fuses iden>fied as replaceable in flight:
! There must be one spare of each ra>ng or 50
percent spare fuses of each ra>ng, whichever is greater
! The spare fuse(s) must be readily accessible to any
Circuit Protec>on – AC 43
• A circuit breaker must be rated so that it will open before:
! The current ra>ng of the wire aQached to it is
exceeded
! The cumula>ve ra>ng of all loads connected to it are
exceeded
Circuit Protec>on – AC 43
Circuit Protec>on – AC 43
• A circuit breaker must always open before any component downstream can overheat and
generate smoke or fire
• Wires must be sized to carry con>nuous current in excess of the circuit protec>ve device ra>ng
! Circuit breakers are designed as circuit protec>on for
the wire, not for protec>on of black boxes or components
• Circuit protec>on should be as close to the power bus/source as possible
Circuit Protec>on – AC 43
• Use of a circuit breaker as a switch is not recommended
! Use of a circuit breaker as a switch will decrease the
life of the circuit breaker
• Automa>c reset circuit breakers, that
automa>cally reset themselves periodically, are not recommended
• Circuit breakers should be periodically cycled
with no load to enhance contact performance by cleaning contaminants from the contact surfaces
Circuit Protec>on
• Protec>on based on current not voltage • Circuit breaker:
! Automa>cally opens a circuit any >me excessive
current flows through it
! Pilot can reset
! Mechanic can disable with zip >e
• Fuse:
! One use device
• Internal wire or metal strip melts away
! Slow and fast blow types
• Slow blow are used for devices that have a large startup
Circuit Protec>on
• Current Limiter:
! Very large slow blow fuse
Switches
• Switches should be derated from their nominal current ra>ng for the following types of circuits:
! Circuits containing incandescent lamps
! Induc>ve circuits have magne>c energy stored in
solenoid or relay coils
Switches
• Dera>ng a switch will obtain reasonable switch efficiency and service life
• Any abnormal side to side movement of the switch should be an alert to imminent failure • “On-‐off” two-‐posi>on switches should be
mounted so that the “on” posi>on is reached by an upward or forward movement of the toggle • Inadvertent opera>on of switches can be
prevented by moun>ng suitable guards over the switches
Grounding
• Inadequate bonding or grounding can lead to unreliable opera>on of systems, e.g., EMI,
electrosta>c discharge damage to sensi>ve
electronics, personnel shock hazard, or damage from lightning strike
• Ground types:
! AC returns ! DC returns ! All others
Grounding
• For distributed power systems, the power return point for an alterna>ve power source should be separated
• Power return or fault current ground
connec>ons within flammable vapor areas must be avoided
Bonding
• The process of electrically connec>ng all isolated components to the aircra& structure
• Provides a path for return current from the components
• Provides a low-‐impedance path to ground to
minimize radio interference from sta>c electrical charges
• Provides a path to ground to dissipate sta>c charge from fire hazards like fuel systems
Bonding
• All conduc>ng objects on the exterior of the airframe must be electrically connected to the airframe through mechanical joints, conduc>ve hinges, or bond straps capable of conduc>ng sta>c charges and lightning strikes
• All isolated conduc>ng parts inside and outside the aircra&, having an area greater than 3 in2
and a linear dimension over 3 inches must be bonded to the aircra& structure
Bonding
• The metallic conduit should be bonded to the aircra& structure at each termina>ng and break point
• Bonding connec>ons should be secure and free from corrosion
! Stainless steel components use copper jumpers
• Bonding jumpers should be made as short as prac>cable
• Resistance of each connec>on does not exceed 0.003 ohm
Bonding
• Bond aQachment hardware selec>on considera>ons:
! Mechanical strength ! Ease of installa>on
Electrical System
• BaQery
! Stores electrical energy
! Provides DC electrical energy ! Starts engine(s)
! Filters power
! Provides needed power during short high load
situa>ons
! Must be recharged
• A baQery stores only about 10 to 30 minutes worth of
energy
• Recharging comes from engine driven alternator/
BaQery and Master Switch
A reverse-‐biased diode installed across the coil of the baQery contactor allows the induced current that is produced when the master switch contacts open
to be dissipated in the coil rather than arcing across the switch contacts.
Electrical Load
• Examples:
! Radios and Instruments
• Radios take much more power when transmipng
! Lights
! Pitot tube heat
! Deicing hea>ng elements ! Flap and trim motors
! Entertainment systems ! Charging baQery
Electrical Load
• Electrical power load is constantly changing and greater than the baQery can provide
! Requires an engine driven power source that can
regulate/vary the amount of power provided
• Power sources
! Engine driven generators or alternators ! Auxiliary Power Unit (APU)
Ground Power Unit (GPU)
• Source of electric energy external to the aircra&
! BaQery cart
! Engine driven generator
• Uses:
! Start aircra&
GPU Circuit
Single Engine Power System
Twin Engine Power System
Light twin-‐engine aircra& electrical power system using individual electronic voltage regulators and overvoltage protectors. The alternator paralleling circuit is built into the voltage regulators.
Used to balance parallel power by keeping voltage the same
DC Generators
• DC generators have slip rings that are split to create DC voltage
! The split slip ring is called the commutator
• Generators are rated (sized) by the amount of current they provide at a given voltage
! e.g. 60 A at 12 volts
! Ra>ng is stamped on the generator case
• More coils reduce the voltage ripple and provide a “cleaner” power source
Field Frame
DC Generators
• Field frame
! Holds field windings/coil
! The magne>c material holding the coil is called the
field pole shoes
• Made of laminated iron
! Reduces the eddy current effects
• Has a residual magne>c field
! If the field coils are not energized, the residual magne>c field
creates a “residual voltage” when the generator is turned
! Enables a generator to work without a baQery
• Residual magne>c field can be restored by flashing the
DC Generators
• Field coils
! Used to generate the magne>c field that generates
the electricity
! The higher the current through the field coils the
stronger the magne>c field
• The higher the output of the generator
• Varying the field coil current varies the output of the
generator
! Should be a low resistance
DC Generator Armature
DC Generators Types
• Defined by how the field coils are arranged • Series Wound with armature coils
! Never used in aircra&
• Parallel (Shunt) Wound with armature coils
• Compound Wound
! Has both series and parallel wound field coils ! Best type
! Interpoles are used to counteract field distor>on
• Overcomes the effect of armature reac>on
DC Generators Mechanical Regulators
DC Generators Mechanical Regulators
• Also called vibrator-‐type voltage regulator
• Controls the output voltage by controlling how much current goes to the field coil
! Changes the resistance in series with the field coil to
control the current
! Higher resistance -‐> lower field current -‐> lower
power/voltage output
! Lower resistance -‐> higher field current -‐> higher
power/voltage output
• Uses three relays to control voltage, current limits and reverse current
DC Generators Mechanical Regulators
DC Generators Mechanical Regulators
• Relays:
! Voltage Regulator
• Opens (high resistance) and closes (lower resistances)
• Constantly pulsing
! Generates a lot of EMI noise
• The longer closed the more current flows through the field
coils
! Higher power output
! Higher current and/or voltage
! Current Limiter
DC Generators Mechanical Regulators
• Relays:
! Reverse Current
• Disconnects baQery from the generator if the baQery
voltage is higher than the generator
! Prevents draining of baQery
• If it fails, current flows through the generator armature
opposite the normal direc>on and through the shunt field in the normal direc>on
DC Generators Maintenance
• Check belt and moun>ng • Check connec>ons
• Clean all oil and dust
! Track down source of oil
• Check brushes
! At least 1/2 their original length
• Usually has a wear mark
! Pig tail is secure
DC Generators Maintenance
• Check brushes
! Check spring strength
• Weak spring will cause brushes to bounce and create
arcing
! Shape end of new brushes
• Check gap between commutator bars
! Gap should be at least as deep as the width of the
mica (insulator)
DC Generators Maintenance
• Growler Test
! Checks for shorted coils in generators or motors ! Tester creates a magne>c field in each coil
• If the coil is shorted, the output voltage will be low
! Can be measure with a volt meter or light
! Video
• Test insula>on with a Megohmmeter (Megger)
! Measures very high resistance ranges with high
voltage
DC Generators Dual
• Dual generator systems have an equalizing circuit that insures the two generators are pupng out the same voltage
! Raises the low generator and lowers the high
DC Generators Dual
DC Generators -‐ FAA Ques>on
• If any one generator in a 24-‐volt dc system shows low voltage, the most likely cause is
A. an out-‐of-‐adjustment voltage regulator. B. shorted or grounded wiring.
C. a defec>ve reverse current cutout relay.
DC Alternator
Stator or Armature Winding
DC Alternator
Stator or Armature Winding Field Winding
DC Alternator
DC Alternator
• Components:
! Stator (Armature) windings (coil)
• The power comes from the stator winding
• Loca>on on the case and doesn’t rotate
! Field windings (coil)
• Rotates
• Smooth, gapless slip rings
• No permanent magnet
! Diodes
• Converts AC to DC
! Regulator
DC Alternator
• Advantages:
! Lighter – no permanent magnets ! Slip ring used for field coils
• Lower current requirements
• Smooth
• Brushes last longer
• No EMI
! AC to DC conversion done by diodes
• Less EMI
DC Alternator
• Advantages:
! Solid state regulator
• Less EMI
• Wider adjustment range
! Power at lower RPMs
• Last longer than mechanical regulators
• Disadvantages:
! Needs baQery power to provide startup current for
DC Alternator
• Stator
! Usually three phase
• Six poles
! Two per phase
! The frequency of the wave form is determined by
Typical Charging System
ALT
Power Bus Bar Alt Out
Alt Out Breaker B Main Solenoid Shunt Resister Amp Meter BaQery + - Over Voltage Sensor Red Orange Black Alt Fld Alt Fld Breaker Voltage Regulator/ ACU S Alt Switch A F F LO/OV Light I Main Switch
DC Alternator
• Solid state regulator
! Components:
• Regulator
• Overvoltage protec>on
• Packaged separately, combined or built into alternator
! Regulator
• Regulates field winding current
• Circuit is very similar to solid state voltage regulator
! Zener diode used to reference alternator output voltage ! Transistors control field winding current
! Overvoltage protec>on
Alternator Troubleshoo>ng Steps
• Setup
• Connec>ons
• Electrical Components • Finish Up
Setup
• Avionic must be turned off
! Protects them from damage
• Master switch – On – when checking voltage
• Master switch – Off – when checking resistance • Select mul>-‐meter range before measuring
• Secure item before running engine • Check circuit breakers
Connec>ons
• Check all mechanical connec>ons are >ght • Check grounding straps
• Cleanup all corrosion
• Check for damaged insula>on
• Recommend customer replace old aluminum baQery cable
! BeQer cold starts
! Save money through longer component life
• Check alternator belt
Typical Charging System
ALT
Power Bus Bar Alt Out
Alt Out Breaker B Main Solenoid Shunt Resister Amp Meter BaQery + - Over Voltage Sensor Red Orange Black Alt Fld Alt Fld Breaker Voltage Regulator/ ACU S Alt Switch A F F LO/OV Light I Main Switch
Electrical Components
• Voltage Tes>ng Setup (Voltage On)
! Master switch (Bat & Alt) -‐ On ! Alternator field switch – On
! Alternator field and Main alternator breaker – On ! To generate a load, turn landing lights on
• Check Amp Meter with load on
! If needle deflects, it is OK
! If no deflec>on plus voltage on connec>ons and
Voltage Regulator
• With Voltage On, check voltage regulator pins
! All pins should be close to Power Bus Bar voltage
• If Pin S is low, check Over Voltage Sensor (OVS) connec>ons
! If OVS connec>ons are good, OVS is bad
• If Pin F is low
! Disconnect Pin F to alternator lead
! If Pin F is s>ll low, replace Voltage Regulator
• Regulator is shorted, also check if alternator field shorted
Voltage Regulator
• If Pin A is low
! Usually a connec>on problem
• If Pin I is high and LV/OV light is out
Alternator
• Disconnect alternator leads and check alternator – voltage off
• Check resistance between F (field lead) and ground connec>on
! Range – 3 to 6 ohms
! If low, field coil is shorted -‐ replace alternator ! If high
• Service brushes and clean commutator
Alternator
• Check for open Stator by measuring resistance between B (baQery lead) and ground
! If high, stator is open and alternator needs to be
replaced
! May have to use “diode” mul>-‐meter sepng
• Check for shorted diode bridge
! Place a mul>-‐meter in series with alternator B lead
to measure leakage current
! Power on
! If leakage current is over 0.5 mA, bridge is bad –
Alternator
• Check for open diode bridge
! Power on, engine at 1500 RPM and lights on ! Check AC voltage on B lead
Alternator
• Check alternator output
! Install mul>-‐meter to measure current in to F lead ! Power on, engine at 1500 RPM and lights on
! If current is 3.5 A or higher and alternator output is
s>ll low, replace alternator
• If s>ll unable to determine problem, run external regulator test outlined in Alternator Test
Finish Up
• Do a final complete system test with engine running and lights on
• Charge/test baQery
! Remember Diamond DA42 crash
• Reinstall and >ghten all components • Clean aircra&
! Return aircra& in as-‐good or beQer shape than you
received it
Large Aircra& Electrical Power
• Some turbine engine combine a starter motor and generator in a single unit
! The windings serve double duty
! Power is applied in the starter mode
! Power is produced in the generator mode
• AC (Alterna>ng Current) power is used on large aircra&
! Usually run at high voltage
• Low current means less power loss in wiring
! Easy to convert to different voltages with a
Large Aircra& Electrical Power
• AC (Alterna>ng Current) power is used on large aircra&
! Commonly run at 400 Hz ! Voltage must be regulated
! Frequency must be >ghtly controlled ! Mul>ple generator systems:
• Matched voltage
• Matched frequency
• Synchronized AC wave forms
! In phase
Large Aircra& Electrical Power
• AC (Alterna>ng Current) power is used on large aircra&
! Constant Speed Drives (CSD) are used to control
Large Aircra& Electrical Power
• AC (Alterna>ng Current) power is used on large aircra&
! Constant Speed Drives (CSD) are used to control
generator speed and phase
• Uses a mechanical transmission to control the frequency
(speed) and phase
• Transmission consists of a hydraulic pump driving a
hydraulic motor
! The amount of fluid going to the motor is varied to control the
speed and phase
• Usually oil cooled
• Can be electrically taken off line with a cockpit switch
• In-‐flight failures can only be fixed on the ground
Large Aircra& Electrical Power
• AC (Alterna>ng Current) power is used on large aircra&
! Integrated Drive Generator (IDG) is a brushless
generator
• Used in high power applica>ons
• Has a built-‐in generator that provides the field current
when the generator turns
! A generator inside a generator
• If metal found in oil, replace unit
! AC voltage can be converted to low voltage DC with a
DC to AC Converter
• Called invertors
• Generates AC by switching the DC
! Method 1: Switch DC on and off ! Method 2: Switch direc>on of DC
• Switching is accomplished by:
! Electric motor
DC Electric Motors
• Very similar to generator except electric power is used to create rota>on
• Major components
! Armature assembly ! Field assembly
! Brush assembly ! End frame
DC Electric Motors
• Types (based on the field windings):
! Series
• Field windings are a few turns of heavy wire connected in
series with the armature winding
• Good star>ng torque
! High startup current
! More current at low RPMs
• Bad speed control
! Shunt (Parallel)
• Good speed control
DC Electric Motors
• Direc>on Change:
! Change the current direc>on in the field windings ! Change the current direc>on in the armature
windings
! Changing both field and armature windings will not
change direc>on
! Some motors have two field windings in opposite
direc>ons to enable direc>on switching
• Speed can be varied by changing field winding current
• Brushless motors replace the commutator with switching transistor
DC Electric Motors
• Armature Brake:
! Fric>on type brake applied to the armature
! A spring is used to apply the brake force and an
electric magnet is used to withdraw the brake
• Stops the motor quickly when the electric power is
removed
External Lights
• Types:
! Posi>on (Naviga>on)
• Green – right wing >p
• Red – le& wing >p
• White -‐ ver>cal stabilizer
! An>-‐collision
• Types:
! Rota>ng beam lights ! White strobe
! Landing ! Taxi lights
! TSO light required in IFR experimental aircra&
Miscellaneous
• AC 43.13-‐1B 11-‐35(d) -‐ In installa>ons where the ammeter is in the generator or alternator lead and the regulator system does not limit the
maximum current that the generator or
alternator can deliver, the ammeter can be redlined at 100 percent of the generator or alternator ra>ng
• Most accurate type of frequency-‐measuring
instrument is an integrated circuit chip having a clock circuit
Miscellaneous
• When using voltage to check a circuits
resistance, the input voltage must be held constant
FAA Ques>on
• How can it be determined if a transformer
winding has some of its turns shorted together?
a. Measure the input voltage with an ohmmeter. b. The output voltage will be high.
c. The transformer will get hot in normal opera>on.