ELECTRICAL SYSTEM

Question 1

What is the PA44 electrical system?

Answer 1

• negative-ground (negative terminal connected to ground)
• dual-fed (electrical power from 2 alternators)
• split-bus
• two-belt driven
• 28 Volt 65 Amp

Question 2

What does the alternators have to protect it from a malfunction?

Answer 2

• voltage regulator
• overvoltage relay

Question 3

What is a voltage regulator?

Answer 3

• electronic device that maintains a constant output of voltage

Question 4

What is an over voltage relay?

Answer 4

• a device that will take the alternator offline if it exceeds 32 volts

Question 5

What is an alternator?

Answer 5

• it is belt driven, as it rotates it sends a DC (Direct Current going one direction) voltage to charge the BATT

Question 6

What are the alternators limitations?

Answer 6

• max load ground is 60 amps
• max load flight is 65 amps

Question 7

What is the role of the BATT in the a/c?

Answer 7

• aids in starting the a/c
• use of electrical equipment when a/c is not running
• electrical storage for alternators

Question 8

What is the role of circuit breakers?

Answer 8

• protect the electrical system
• contains a metal piece where electric will move through
• metal will expand due to heat
• metal will get hot and expand a great deal and “pop” the circuit
• re-setting the circuit, allow for a cool down period (few minutes)
• fire could start with repeated re-setting

Question 9

What is the Emergency BATT?

Answer 9

• provides electrical power to a/c during complete electrical failure or when electric is not sufficient
• powers standby instruments, all PFD functions (except COM 2/NAV 2)
• 30 minutes of electrical power
• isolated from emergency bus by a relay
• diode isolated, allows for charging during normal ops

Question 10

What is a solenoid contactor?

Answer 10

• high powered switch that uses coils to activate set of contacts

Question 11

What is the BATT bus?

Answer 11

• connected directly to BATT
• BATT power still available when BATT master is off
• provides power to clock, engine/flight/heater hobbs

Question 12

What is the ESS Bus?

Answer 12

• is a power distribution bus in an aircraft that supplies power to critical equipment
• 70 amp circuit breaker
• a dedicated electrical circuit in a system, particularly in aircraft, that provides power to critical components which must function even in emergency situations

Question 13

What is the acronym “BATMAN” stand for?

Answer 13

Battery bus
Avionics bus #1
Tie bus
Main bus
Avionics bus #2
Non-essential bus

Question 14

What is a tie bus?

Answer 14

• simply connects two bus bars together
• like the engine generators or auxiliary power unit (APU), to be connected together (tied) on a single electrical bus

Question 15

What is a non-essential bus?

Answer 15

• power circuit that supplies power to systems or components that are not critical for the safe operation of the aircraft
• can be deactivated quickly to help reduce electrical load in case of alternator failures

Question 16

Can we start the a/c externally on the ground?

Answer 16

• external can be used to power the a/c
• good to start one engine w/ external power & other with a/c power

Question 17

What happens when you turn on the alternators?

Answer 17

• positive output fed through shunts (device creates low resistance for electrical currents) to tie bus
• current from tie bus fed to avionics bus through a solenoid contacter

Question 18

What is a volt? What is an amp?

Answer 18

• force of an electrical current (pressure)
• volume of electrons flowing

Question 19

Limitations of the Main & Emergency BATT?

Answer 19

• Main (minimum 25 volts & maximum 32 volts)
• Emergency (minimum 20 volts, minimum for IFR 23.3 volts & maximum 32 volts)

Question 20

What are the specifications of the BATT?

Answer 20

• 13.6 amp hr. 24 volt
• nose compartment
• charged by 14 volt alternators
• BATT & alternator incorporate a contactor
• BATT master switch activates BATT contractor which connects the BATT to the system (keeps large amounts of electricity from pilot & reduces weights/wires)

Question 21

What are the specifications of the G1000 system?

Answer 21

• 10” lcd screens PFD & MFD

Question 22

What features are equipped on the PFD?

Answer 22

• AHRS
• ADC
• VOR/Localizer/GS
• CAS (crew alerting system) warning messages

Question 23

What features are equipped on the MFD?

Answer 23

• engine parameters
• a/c system parameters
• various maps
• traffic map, weather, TAWS (terrain avoidance & warning system)

Question 24

What is AHRS? (MAG & AHRS-W)

Answer 24

• attitude heading reference system
• inputs: ADC, GPS, Magnetometer
• outputs: attitude indicator, heading indicator, rate of turn, slip/skid, wind vector

Question 25

What is ADC?

Answer 25

• air data computer
• inputs: OAT probe, pitot/static, alternate static
• outputs: OAT, TAS, IAS, VSI, ALT, E6B calc., wind vectors, mode c transponder

Question 26

What are solid state gyros?

Answer 26

• there are in the G1000 system
• mounted vertically & horizontally
• tiny free floating accelerometer works off of Coriolis acceleration
• some use laser lights that track time it takes to move around a fixed object
• they are durable & accurate

Question 27

What is a magnetometer?

Answer 27

• 3 soft iron rods, wound in copper coils that can accept the flux lines of Earth
• measures amount of flux from the Earths magnetic field and calculates current heading

Question 28

What is a VOR?

Answer 28

• Very High Omnidirectional Range
• VOR receiver receives 2 signal (reference & variable signal)
• broadcasts signal in all directions
• detects the phase difference to determine the radial

Question 29

What is a DME?

Answer 29

• Distance Measuring Equip.
• interrogation frequency pulse received by ground stations
• sends reply pulse where a/c measures the time between the process to determine distance

Question 30

What is GPS?

Answer 30

• Global Positioning System
• Spaced based nav.
• 30+ satellites
• 24 for timing & range that orbit Earth
• satellites use an atomic clock which is down to the billionth of a second
• 3 sats for 2D (position), 4 sats for 3D (position & altitude), 5 sats for RAIM, 6 sats for FDE
• position, velocity, & time

Question 31

What is WAAS?

Answer 31

• Wide Area Augmentation System
• increases accuracy of GPS system
• 50 ft to 10 ft of accuracy
• reference stations, master stations, geo satellites, uplink station

Question 32

What is RAIM?

Answer 32

• Receiver Autonomous Integrity Monitoring
• monitors strength & integrity of GPS signals
• FDE will exclude or removed faulty signal

Question 33

What is the ILS system?

Answer 33

• Instrument Landing System
• approach
• guidance, range, & visual
  er side, 10 NM 35 degrees either side, width 700 ft.

Question 34

ILS Guidance

Answer 34

• localizer, antenna DER, two signals emitted, coverage 18 NM 10 degrees either side, 10 NM 35 degrees either side, width 700 ft.
• glide slope: localizer on its side, 3 degree glide slope, beam 1.4 degrees thick 0.7 is full scale deflection 750-1250 feet past approach end

Question 35

ILS Range

Answer 35

• DME
• marker beacons: used to identify fixes, antennas on ground, flashing lights Outer (blue), Middle (amber), Inner (white)
• we use GPS

Question 36

Visual Info for ILS

Answer 36

• approach lights
• touchdown/centerline lights
• runway lighting
• approach lighting system
• runway threshold/threshold lights
• REIL
• runway pavement

Question 37

What is an HSI?

Answer 37

• A Horizontal Situation Indicator (HSI) is a flight instrument that shows an aircraft’s position and orientation relative to its course
• It’s a vital navigation tool that combines a heading indicator with a course deviation indicator (CDI)

Question 38

What are the Autopilot Limitations?

Answer 38

• AP disengaged during T/O & LDG
• 400 ft. T/O or subsequent climb
• 1000 ft. cruise & descent
• 200 ft. on approach
• speed on approach 90 KTS
• other than approach 80 KTS
• max speed 190
• max fuel imbalance 10 gal.
• AP prohibited during OEI
• pitch +/- 50 degrees
• roll +/- 75 degrees