Electrical (all).txt

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Electrical (all).txt
2013-11-19 20:34:49

Electrical systems
Show Answers:

  1. What is the generator cut-in range
  2. Generator output?
    • 115-220V
    • 3-phase
    • 320-480 cycles per second
  3. What range does the airframe mounted gearbox shift
    65-75% RPM
  4. Does the OFF position stop the generator?
    No, it disconnects it from its bus
  5. What three situations will the generator caution light illuminate
    • generator malfunction
    • bus fault
    • switched to OFF
  6. When a generator drops off line due to a bus fault, can you get a good crossover?
    No, If the malfunction is a bus fault, the protection panel will not allow a generator reset or bus transfer to the opposite generator
  7. What does the static inverter power?
    • either engine start (ground or air)
    • right engine AC sensors
    • both fuel quantity sensors and oxygen quantity
  8. How is the static inverter activated?
    • pushing either engine start button
    • advancing either throttle to AB
    • holding the fuel/oxygen check switch
  9. How are the engine Tachometers powered?
    they have their own independent generator in the engine accessory gearbox
  10. Name the AC powered engine sensors
    • oil pressure
    • fuel flow (also needs left essential DC)
    • hydraulic pressure
    • fuel quantity
    • oxygen quantity
    • Tachometer
  11. How and which busses does the APU power?
    The APU connects to the AC busses which power the TRUs which power the DC busses
  12. Indications of generator fail with good crossover
    illumination of MASTER CAUTION and generator lights and caution alert messages
  13. How many times can a generator be reset?
  14. Right gen fail no cross indications
    • HUD and UFCP go blank
    • MFD reverts to backup display
    • right oil pressure and fuel flow, oxygen quantity and all three fuel quantity show OFF
    • Flight control hydraulic indicator freezes at last position
  15. Left gen fail no cross indications
    • Illumination of the AOA indicator lights and CAUTION alert message on the HUD and MFD
    • left oil pressure and fuel flow indicators show OFF
    • utility hydraulic pressure gauge freezes
  16. Airframe mounted gearbox failure indications
    MASTER CAUTION, generator and hydraulic lights
  17. Gearbox failure to shift indications
    • occurs when moving throttle(s) through 65-75% RPM
    • Indications are the same for a generator failure
  18. Partial electric failure indications
    same as gen fail with crossover
  19. Partial electric failure indications with no cross
    • Flaps and boost pump operates slower or not at all
    • Slow or inop boost pump may lead to Fuel low pressure light
    • HUD operation/display may be affected
    • TRUs may drop offline
  20. How is the Caution Light Panel and MASTER CAUTION light powered
    • both are DC in bright and right AC in DIM
    • FIRE light is bright and DC only
  21. How can you light the WCA lights without DC power
    Set to DIM
  22. How can you light the WCA lights without AC power
    Set to BRIGHT
  23. Does a GENERATOR light always mean a generator failure?
  24. HYDRAULIC light illuminate when hydraulic pressure drops below ___ or what?
    1500, overtemp
  25. When does the FUEL PRESSURE light illuminate?
    fuel pressure drops below 6psi (normally 10)
  26. When does the ENG ANTI-ICE ON light illuminate?
    switched on, right fail gen no cross
  27. When is the ANTI-ICE system on w/o the light?
    below 65% RPM
  28. When does the OXYGEN light illuminate?
    below 1 liter, may blink due to sloshing
  29. When does the FUEL LOW light illuminate?
    7.5 seconds at 250lbs
  30. Will the MASTER CAUTION light reilluminate after being reset when the second tank goes below 250?
  31. What is the approximate life of the battery after TRU failure?
  32. During normal operation, what is the primary DC power source
  33. Which of the following aircraft components are inoperative when there is complete DC electrical failure
    • MFD
    • AB operation
    • Crossfeed operation
    • Landing Gear Indicators (Bright mode)
    • Fire warning lights
    • EED
  34. The right TRU receives power from the ___ and the left receives power from the ___
    • right AC bus contactor
    • left AC bus contactor
  35. Can one TRU carry the entire DC load
  36. What if both TRUs fail?
    the battery picks up the DC load for only the two essential DC busses
  37. When is the non essential DC bus shed?
    when the bus drops from 28 VDC to 24 VDC
  38. What may cause a momentary illumination of XMFR RECT OUT?
    • flaps moving
    • fuel/oxygen quantity check
    • AB ignition
  39. Is the battery charging when the APU is connected?
  40. What three times is battery power required?
    • non-APU start
    • both TRUs fail
    • both gen inop
  41. Indications of a single TRU fail
    AVIONICS alert on the HUD/MFD
  42. Indications of both TRU fail
    MASTER CAUTION, XMFR RECT OUT illuminates and caution alert is displayed on MFD
  43. If ON, when does the battery drop off line?
    drops below 10V
  44. If ON, indications of weak battery
    • low volumes
    • raspy interphone and poor radio transmission capability
    • caution panel lights dim
  45. If the battery is on, power can be conserved by turning off what
    • MFD
    • EED
    • UHF backup control
    • EGI
    • emergency flood lights
    • TCAS
  46. Total DC failure recovery considerations
    chase ship or to a VFR field (Lost all comm/navigation capability)
  47. Right essential DC bus failure recovery considerations
    • standyby instruments for control and performance
    • stay VMC
    • use chase ship to lead back
    • Squawk emer and use NAV B/U for the VOR
    • Alternate gear extension
  48. Left essential DS bus failure recovery considerations
    • stay VMC or use chase to lead back
    • No-flap required
  49. Total electrical failure recovery considerations
    • standy by instruments only
    • Idle to Mil only, no AB.
    • No airstart
    • alternate gear extension with no indication
    • No flaps trim or speedbrake
  50. Right AC bus Failure considerations
    • MDP and HUD inop.
    • Only backups on MFD.
    • Must use UHF/NAV backup control panel.
    • No flaps, trim, right boost pump, A/C and eventually canopy seal
  51. Left AC bus failure considerations
    • mostly a concern at night since normal aircraft lighting is affected.
    • SAS, rudder trim and left boost pump are inop
  52. What is AC power provided and how are they powered?
    2 independent generators powered through airframe mounted gearbox
  53. TRUs convert power from AC to DC or DC to AC?
    AC to DC
  54. TRUs convert ___ - ___ volt three-phase AC power to __ ___ DC power
    • 115-200
    • 28 Volt
  55. What is the purpose of the TRUs?
    Provide primary DC power source
  56. What is the alternate DC power source?
    24-volt lead acid battery
  57. What two things does the battery provide power to when the TRUs are offline?
    Essential DC busses and battery bus
  58. What position should the battery switch be in for an APU start?
  59. What is the primary purpose of the battery?
    Engine Starts
  60. What is the static inverter powered by?
    Battery bus
  61. What does the static inverter do?
    Converts DC to AC for instruments monitoring right engine start
  62. What three ways is electrical power distributed in the T-38?
    • Left and right AC busses
    • 3 DC busses (1 non-essential)
    • and battery bus
  63. EGI storage and memory requires at least ___ secs of aircraft power after turning off the EGI switch on the AAP
  64. AC Electrical Components
    • (GAP SAAB)
    • Generator
    • AC Bus
    • Protection Panels
    • Static Inverter
    • AC-powered instruments
    • APU
    • Bus contactors/transfer relays
  65. What are the three main specifications of the generators?
    • three phase
    • 320-480 cycle
    • 115-200 volt
  66. What does the engine-mounted gearbox power besides the generator?
    Hydraulic pump
  67. What RPM does gearbox shift occur?
  68. Each generator supplies AC electrical power to what?
    AC electrical bus
  69. Generators normally carry ___ the electrical load
  70. If one generator fails, the other will supply AC power to both systems dependent on what?
    Transfer relay
  71. What are the three generator switch positions?
    On, Off, and Reset
  72. What does putting the gen switch to OFF do?
    Disconnects the generator from the circuit. DOES NOT turn off the generator (engine windmilling)
  73. How would you attempt to get a failed generator back online?
    Select RESET then ON
  74. When do GEN caution lights illuminate?
    GEN switch in off or any GEN malfunction or bus fault
  75. How many bus contactors are there for each generator and where are they?
    2 located in the aft electrical compartment (behind the rear seat)
  76. What is contained within the bus contactors?
    Main relays and transfer relays
  77. What is the function of the main relays within the bus contractor?
    Connects generators to their respective busses
  78. What is the function of the transfer relays within the bus contractor?
    Connect bus loads to opposite generator in case of a malfunction.
  79. What does the transfer relay do in the event of a bus fault?
    Does not allow a transfer to the other generator
  80. What are the 2 times a generator will disconnect from its bus?
    Gen malfunction (cross) and bus fault (no cross)
  81. What are the 2 times in the checklist that the transfer relay (crossover) is checked?
    R-L checked on R engine start. R-L and L-R checked during before taxi check
  82. What are the 3 ways to activate the static inverter?
    • Placing either throttle in AB
    • using fuel/o2 test switch
    • pressing start button
  83. Static inverter provides power to the following equipment
    • Right engine AC instruments
    • Ignition - L and R
    • Fuel and O2 quantity gauges
  84. What do most standard AC instruments do when they fail?
    They freeze (AC lies, DC dies)
  85. What would happen to your instruments with a loss of AC?
    Loss of EED indications (oil, fuel flow, fuel quantity) hydraulic and O2 freeze
  86. What type of power does the APU provide?
    AC (replicating generators and engines running)
  87. What happens when a generator connects to a bus after an APU is connected?
    External power relay disconnects the APU
  88. What must you sometimes do to get the aircraft to accept APU power?
    Cycle battery off, then on
  89. What type and amount of power do the TRUs put out?
    28V DC
  90. What happens if one TRU fails?
    The other will carry the entire DC electrical load
  91. How many and what types of DC busses are there?
    3 - 2 essential, 1 non-essential
  92. What DC busses are powered if the battery is the only source of power?
    2 essential busses
  93. What are the 4 situations when the battery would be the only source of DC power?
    • Starts without an APU
    • both TRUs failed
    • Both GENs inop
    • DC components causing a drain on DC bus below 24 volts
  94. What three things are on the battery bus?
    • static inverter
    • L/R start control
    • L/R afterburner ignition control
  95. What is the min volts for the battery to connect to the DC bus?
    18 volts
  96. What is the min voltage for the battery to stay online?
    10 volts
  97. How long (approximately) will battery power last?
    15 mins at 80% charge
  98. What are the DC-powered instruments and displays?
    • (FEMS)
    • Flap position indicator
    • EED (EGT. Nozzle position)
    • MFD
    • standby attitude indicator
  99. Are map lights DC or AC?
  100. Is interior lighting DC or AC?
  101. During an AC power failure, what will happen to the interior lights?
    They will revert to DC - bright during night, dim during day
  102. Is bright mode for the WCA system AC or DC?
  103. What are the 4 instruments not affected by the caution/light panel dimmer switch?
    • Marker beacon
    • FIRE lights
    • AOA
    • takeoff trim indicator lights
  104. How do you dim the WCA lights?
    Ensure rheostat is out of off, place switch in DIM to change from DC to AC
  105. What happens of an AC power failure occurs for the WCA lights?
    Revert to DC (bright) mode
  106. What 2 lights cannot be dimmed?
    FIRE lights and Takeoff trim indicator
  107. What 3 lights are inop with a DC failure?
    • FIRE lights
    • Master Caution Lights
    • RCP nosegear light
  108. What 2 things have to happen for the tone test pattern to work?
    MDP timed-in and gear warning silence button depressed
  109. What 3 things does the test switch on the right front console test?
    • tone test pattern
    • fire detection system
    • and master caution and caution panel lights
  110. What are the 2 places the rotating beacon is located?
    Bottom of fuselage and vertical stab
  111. What 3 places are position lights located?
    wintips, vertical stab, lower fuselage
  112. What are the two main features of the landing/taxi light?
    Retractable, and dual filament
  113. What two things must be activated for the landing/taxi light to be extended?
    Position lights ON, and landing gear handle DOWN
  114. When are both filaments in the landing light on?
    When the aircraft is airborne and the gear is down
  115. When is only one filament in the lighting light on?
    When the weight of the aircraft is on the main gear
  116. How long does it take the landing light to retract?
    10 seconds